Corresponding author: Kristine N. White (
Academic editor: C.O. Coleman
Commensal leucothoid amphipods have been collected from the canals of their sponge hosts throughout the Ryukyu Archipelago, Japan. Eleven new species are described in the genus
The
There are currently 14
Specimens were collected via snorkeling and SCUBA at 47 locations throughout the Ryukyu Archipelago: Ishigaki–jima Island (4 locations), Iriomote–jima Island (4), Okinawa–jima Island (21), Yoron–to Island (2), Okinoerabu–jima Island (2), Tokunoshima Island (4), Amami–oshima Island (6), and Yakushima Island (4) (see map in
Entire sponges were isolated in zip-lock plastic bags for subsequent dissection in the laboratory or amphipods were captured individually in situ using a modified squirt bottle (following
Specimens used for morphological analyses were transferred to glycerin, dissected, mounted on slides, and illustrated using a Nikon®Y-IDT drawing tube attached to a Nikon® Eclipse 50I compound microscope. Pencil drawings were scanned and digitally inked in Adobe® Illustrator using a Wacom® Tablet, following the methods of
Descriptions are of males unless noted with sexually dimorphic characters described in a separate section. Terminology used in descriptions follows
Type material and sponge pieces are deposited in the University of the Ryukyus Museum (Fujukan), with the prefix RUMF for museum numbers. Additional material has been deposited in the National Museum of Nature and Science in Tokyo, with the prefix NSMT for museum numbers.
Scale bars in figures represent 0.1 mm unless noted.
Figures legend:
Eyes, if present, generally well developed with 10 or more ommatidia. Mandibles lacking molars, palp three articulate; right lacinia mobilis smaller than left. Maxilliped inner plates fused, palp 4–articulate; outer plates not reaching apex of palp article 1. Coxa 1–4 relatively equal in widths. Pereopods 5–7 bases generally expanded. Minimal to no sexual dimorphism.
Holotype female, 9.6 mm RUMF-ZC-1732, Zanpa Cape, Okinawa–jima Island, Okinawa, reef wall (
Zanpa Cape, Okinawa–jima Island, Okinawa, Japan (
1 specimen, RUMF-ZC-1734, KNW17Aug10; 1 specimen, NSMT-Cr 21871, KNWOkinawa10A; 3 specimens, NSMT-Cr 21872, KNWOkinawa15G; 2 specimens, RUMF-ZC-1735, KNWOkinawa16I; 2 specimens, RUMF-ZC-1736, KNWOkinawa29D; 0.5 specimen, NSMT-Cr 21873, KNWOkinawa34C; 15 specimens, NSMT-Cr 21874, KNWYaku2F; 1 specimen, RUMF-ZC-1737, KNWOkinawa40D.
Ventral cephalic keel anteroventral margin with anteriorly projecting cusp. Right mandible lacinia mobilis with 2 rows of dentition. Maxilliped inner plates with short serrate robust setae. Gnathopod 1 coxa anterior margin serrate; basis anterior margin with 12 medium-length setae, posterior margin with 14 short setae. Gnathopod 2 basis anterior margin with 33 medium-length setae, posterior margin with 7 setae, distal margin with 4 curved setae; ischium with several short posterior and distal setae and posterodistal serrations; carpus distally truncate.
Head. Anterior margin rounded, anterodistal margin evenly rounded; ventral cephalic keel anterior margin excavate, anteroventral margin with anteriorly projecting cusp, ventral margin straight; eyes present with more than 10 ommatidia, oval. Antenna 1 0.3 × body length, flagellum 10–articulate, peduncle article 1 width less than 2 × article 2, accessory flagellum absent. Antenna 2 0.3 × body length, subequal in length with antenna 1, flagellum 8–articulate. Mandibular palp ratio of articles 1–3 1.0: 2.6: 1.7, article 2 with 8–9 long distal setae, article 3 with 2 distal setae, incisors strongly dentate; left mandible with 16 raker spines, lacinia mobilis large, strongly toothed; right mandible with 14 raker spines, lacinia mobilis small, with 2 rows of dentition. Upper lip asymmetrically lobate, anterior margin setose. Lower lip inner lobes fused, bare; outer lobes with small gape, anterior margins setose. Maxilla 1 palp 2–articulate with 4 distal setae; outer plate with 9 distal robust setae and 4 distal slender setae. Maxilla 2 inner plate with 8 slender distal setae, 6 robust marginal setae, and facial setae; outer plate with 2 robust and 6 slender distal setae, 9 slender marginal setae, and facial setae. Maxilliped inner plates distal margin with a v-shaped indentation, with short serrate robust setae; outer plate inner margin smooth, reaching 0.3 × palp article 1, with simple marginal setae, facial setae present; palp article 4 subequal in length with article 3, distally acute.
Pereon. Coxae 1–4 relative widths 1.0: 1.3: 1.0: 1.4. Gnathopod 1 coxa with tiny marginal setae, anterior margin serrate, anterodistal margin produced, rounded, distal margin straight, posterior margin excavate, facial setae absent; basis slightly inflated, anterior margin with 12 short setae, posterior margin with 14 short setae; ischium with posterior setae; carpus linear, distal length 12.9 × width, proximal margin dentate, distal margin with 3 setae; propodus straight, palm dentate with 8 distal setae; dactylus smooth, reaching 0.5 × propodus length. Gnathopod 2 coxa broader than long, subequal in size with coxa 3, smooth, with tiny marginal setae; anterior margin straight, anterodistally rounded, distal margin straight, posterior margin straight, facial setae absent; basis slightly posteriorly expanded, anterior margin with 33 medium setae, posterior margin with 7 setae, distal margin with 4 curved setae; ischium with several short posterior and distal setae and posterodistal serrations; carpus 0.3 × propodus length, curved, distally truncate, anterior margin dentate; propodus with 1 mediofacial setal row displaced to midline, reaching 0.8 × propodus length, with 1 row of submarginal setae, posterior margin smooth, palm convex dentate; dactylus curved, proximal margin smooth, bare, anterior margin distally subacute, reaching 0.6 × propodus length. Pereopod 3 coxa length 1.3 × width, anterodistal corner overriding distal face of coxa 2 and extending below it, smooth, bare, anterior margin straight, distal margin oblique, posterior margin tapered, facial setae absent. Pereopod 4 coxa smooth, bare, anterior margin straight, distal margin evenly rounded, posterior margin tapered, facial setae absent. Pereopods 5–7 coxae facial setae absent; bases width length ratios 1: 1.4, 1: 1.4, 1: 1.3, posterior margins smooth, setose.
Pleon. Epimera 1 and 3 bare, epimeron 2 with ventral setae; epimeron 3 posteroventral corner subquadrate. Uropods 1–3 relative lengths 1.0: 0.8: 1.1. Uropod 1 peduncle and outer ramus 0.9 × inner ramus length; inner ramus with 3 robust setae; outer ramus with 7 robust setae. Uropod 2 peduncle length 0.7 × inner ramus length, outer ramus length 0.6 × inner ramus length; inner ramus with 4 robust setae; outer ramus with 7 robust setae. Uropod 3 peduncle 1.3 × inner ramus length, outer ramus length subequal in length with inner ramus; inner ramus with 4 robust setae; outer ramus with 5 robust setae. Telson 2.7 × longer than wide, apex strongly tridentate.
Gnathopod 1 basis anterior margin with 7 setae, posterior margin with 5 setae. Gnathopod 2 basis anterior margin with 9 long setae, posterior margin bare; ischium with posterodistal setae, smooth.
After the Japanese words ‘aka’, meaning ‘red’, and ‘oni’, meaning ‘barbarian’ and referring to the red color and large size (pronounced ah-ka-oh-nee).
In canals of sponges, spiculose green ball sponge, ?
East China Sea: Okinawa–jima Island (Okinawa), Yakushima (Kagoshima), Japan.
Holotype male, 2.1 mm RUMF-ZC-1738, Bise, Okinawa–jima Island, Okinawa, reef wall (
Bise, Okinawa–jima Island, Okinawa, Japan (
1 specimen, NSMT-Cr 21875, KNWOkinawa23F; 1 specimen, NSMT-Cr 21876, KNWOkinawa27E; 1 specimen, RUMF-ZC-1740, KNWOkinawa29B; 1 specimen, RUMF-ZC-1741, KNWOkinawa29M; 6 specimens, RUMF-ZC-1742, KNWOkinawa30D; 1 specimen, NSMT-Cr 21877, KNWOkinawa31G; 5 specimens, NSMT-Cr 21878, KNWOkinawa39I; 6 specimens, NSMT-Cr 21879, KNWOkinawa43C; 1 specimen, NSMT-Cr 21880, KNWOkinawa50C; 1 specimen, RUMF-ZC-1743, KNWOkinawa55A; 5 specimens, RUMF-ZC-1795, KNWYaku3G; 1 specimen, RUMF-ZC-1847, KNWOkinawa15E; 1 specimen, RUMF-ZC-1848, KNWOkinawa15E; 4 specimens, NSMT-Cr 21991, KNWOkinawa15E; 1 specimen, RUMF-ZC-1849, KNWOkinawa21C; 2 specimens, NSMT-Cr 21992, KNWOkinawa13E.
Head anterodistal margin quadrate with cusp. Antenna 1 with many setulate-serrate setae. Maxilla 1 palp 1–articulate, margins constricted. Gnathopod 1 basis proximally widened; propodus palm serrate, saw-like. Gnathopod 2 carpus distally rounded; propodus with 2 mediofacial setal rows, primary mediofacial setal row very short. Pereopods 5–7 bases very narrowly expanded. Female gnathopod 1 basis posterior margin with 7 setae; gnathopod 2 carpus distally truncate.
Head. Anterior margin truncate, anterodistal margin quadrate with cusp; ventral cephalic keel anterior margin transverse, anteroventral margin quadrate, ventral margin straight; eyes with more than 10 ommatidia, round. Antenna 1 0.3 × body length, with setulate-serrate setae, flagellum 4–articulate, peduncle article 1 width less than 2 × article 2, accessory flagellum absent. Antenna 2 0.3 × body length, subequal in length with antenna 1, flagellum 3–articulate. Mandibular palp ratio of articles 1–3 1.0: 3.0: 1.8, article 2 with 5 medium distal setae, article 3 with 2 distal setae, incisors strongly dentate; left mandible lacinia mobilis with 12 raker spines, large, strongly toothed; right mandible with 10 raker spines, lacinia mobilis small, strongly dentate. Upper lip asymmetrically lobate, anterior margin setose. Lower lip inner lobes fused, bare; outer lobes with moderate gape, anterior margins setose. Maxilla 1 palp 1–articulate, margins constricted and with 4 distal setae; outer plate with 5 distal robust setae and 4 distal setae. Maxilla 2 inner plate with 5 robust distal setae; outer plate with 3 robust distal setae and 11 slender distal marginal setae. Maxilliped inner plates distal margin with a v-shaped indentation, with short robust setae; outer plate inner margin smooth, reaching 0.2 × palp article 1, with simple marginal setae, facial setae absent; palp 4–articulate, article 4 subequal in length with article 3, distally acute.
Pereon. Coxae 1–4 relative widths 1.0: 1.0: 0.9: 1.1. Gnathopod 1 coxa smooth, with tiny marginal setae, anterodistal margin produced, subtriangular, distal margin straight, posterior margin excavate, facial setae absent; basis proximally widened, anterior margin bare, posterior margin with 2 setae; ischium bare; carpus linear, distal length 18.8 × width, proximal margin smooth, distal margin bare; propodus straight, palm serrate, saw-like, with 3 robust and 5 short proximal setae; dactylus smooth, reaching 0.4 × propodus length. Gnathopod 2 coxa broader than long, subequal in size to coxa 3, smooth, with tiny marginal setae, anterior margin straight, anterodistally acute, distal and posterior margins straight, facial setae absent; basis linear, anterior margin with 3 setae, posterior margin bare; ischium bare; carpus 0.3 × propodus length, curved, distally rounded, anterior margin smooth; propodus with 2 mediofacial setal rows, primary mediofacial setal row above midline, reaching 0.4 × propodus length, secondary mediofacial setal row with 1 seta, with 1 row of submarginal setae, posterior margin smooth, palm convex, dentate; dactylus curved, proximal margin smooth, with 2 setae, anterior margin distally subacute, reaching 0.6 × propodus length. Pereopod 3 coxa length 0.9 × width, anterodistal corner overriding distal face of coxa 2 and extending below it, smooth, with tiny marginal setae, anterior margin evenly rounded, distal margin slightly convex, posterior margin straight, facial setae absent. Pereopod 4 coxa smooth, with tiny marginal setae, anterior margin tapered, distal margin straight, posterior margin tapered, facial setae absent. Pereopods 5–7 coxae facial setae absent; bases width length ratios 1: 1.9, 1: 1.7, 1: 1.8, posterior margins smooth, setose.
Pleon. Epimera 1 and 3 bare, epimeron 2 with ventral setae; epimeron 3 posteroventral corner subquadrate, produced. Uropods 1–2 relative lengths 1.0: 0.9; inner and outer rami lined with short marginal setae. Uropod 1 peduncle 0.9 × inner ramus length, outer ramus subequal in length with inner ramus length; inner ramus with 2 robust setae, outer ramus with 1 robust seta. Uropod 2 peduncle 0.7 × inner ramus length, outer ramus 0.9 × inner ramus length; inner ramus with 1 robust seta, outer ramus with 2 robust setae. Uropod 3 missing. Telson 2.1 × longer than wide, with plumose facial setae, apex weakly tridentate.
Gnathopod 1 basis anterior margin with 1 seta, posterior margin with 7 setae; ischium with 2 posterior setae; carpus distal margin with 3 setae. Gnathopod 2 basis anterior margin with 10 medium setae, posteromedial margin with 1 seta; carpus distally truncate, reaching 0.5 × propodus length; propodus secondary mediofacial setal row with 4 setae, palm with more prominent tubercles.
Leucothoe bise sp. n., holotype male, 2.1 mm, RUMF-ZC-1738; paratype female, 3.6 mm, RUMF-ZC-1739; paratype male, 3.3 mm RUMF-ZC-1846.
After the Japanese place name, ‘Bise’, and referring to the type locality. (Pronounced bee-say.)
In canals of sponges,
Some sexually dimorphic characters may be due to the larger size of the female. Some specimens have larger serrations on the saw-like gnathopod 1 propodus palm, suggesting morphological variation in this character, perhaps depending on size.
East China Sea: Okinawa–jima Island, Iriomote–jima Island (both Okinawa), Japan.
Holotype male, 4.4 mm RUMF-ZC-1744, Zanpa Cape, Okinawa–jima Island, Okinawa, reef wall (
Zanpa Cape, Okinawa–jima Island, Okinawa, Japan (
2 specimens, KNWOkinawa34E; 2 specimens, KNWIshigaki2C; 1 specimen, RUMF-ZC-1746, KNWOkinawa40E; 1 specimen, NSMT-Cr 21881, KNWOkinawa34F.
Body stout. Antennae robust, short. Ventral cephalic keel anterior margin excavate. Mandibular palp article 2 robust. Maxilla 1 palp 1–articulate. Maxilliped inner plates with short serrate robust setae. Pereopods 5 and 7 coxae with facial setae. Gnathopod 2 stout.
Head. Anterior margin rounded, anterodistal margin subquadrate; ventral cephalic keel anterior margin excavate, anteroventral margin subquadrate, ventral margin oblique; eyes with more than 10 ommatidia, round. Antenna 1 0.3 × body length, flagellum 6–articulate, peduncle article 1 width less than 2 × article 2, accessory flagellum absent. Antenna 2 0.3 × body length, subequal in length with antenna 1, flagellum 6–articulate. Mandibular palp ratio of articles 1–3 1.0: 2.3: 1.8, article 2 robust, with 2–3 long distal setae, article 3 with 2 distal setae, incisors strongly dentate; left mandible with 11 raker spines, lacinia mobilis large, strongly toothed; right mandible with 11 raker spines, lacinia mobilis small, strongly dentate. Upper lip asymmetrically lobate, anterior margin setose. Lower lip inner lobes fused, setose; outer lobes with moderate gape, anterior margins setose. Maxilla 1 palp 1–articulate with 4 distal setae; outer plate with 4 distal robust setae and 10 distal setae. Maxilla 2 inner plate with 7 robust distal setae; outer plate with 3 robust distal setae and 16 slender distal marginal setae. Maxilliped inner plates distal margin with a v-shaped indentation, with short and long serrate robust setae; outer plate inner margin smooth, reaching 0.2 × palp article 1, with simple marginal setae, facial setae absent; palp article 2 with setulate-serrate marginal setae; article 4 subequal in length with article 3, distally acute.
Pereon. Coxae 1–4 relative widths 1.0: 1.2: 0.8: 1.3. Gnathopod 1 coxa smooth, with tiny marginal setae, anterodistal margin produced, rounded, distal margin straight, posterior margin excavate, facial setae absent; basis linear, anterior margin with 3 setae, posterior margin with 1 seta; ischium bare; carpus linear, distal length 12.8 × width, proximal margin dentate, distal margin with 2 short setae; propodus straight, palm dentate with 4 long and 8 short distal setae; dactylus smooth, reaching 0.5 × propodus length. Gnathopod 2 coxa broader than long, subequal in size with coxa 3, smooth, with tiny marginal setae, anterior margin rounded, anterodistally rounded, distal margin straight, posterior margin straight, facial setae absent; basis distally expanded, anterior margin with 7 long setae, posterior margin with 3 setae, posteromedial margin with 1 long seta; ischium with distal, posterior, and posterodistal setae; carpus 0.4 × propodus length, curved, distally tapered, anterior margin smooth; propodus with 1 mediofacial setal row displaced to midline, reaching 0.8 × propodus length, with 1 row of submarginal setae, posterior margin smooth, palm convex, dentate; dactylus curved, proximal margin smooth with 2 setae, anterior margin distally acute, reaching 0.8 × propodus length. Pereopod 3 coxa length 1.4 × width, anterodistal corner overriding distal face of coxa 2 and extending below it, smooth, with tiny marginal setae, anterior margin straight, distal margin slightly convex, posterior margin straight, facial setae absent. Pereopod 4 coxa smooth, bare, anterior margin straight, distal margin evenly rounded, posterior margin tapered, facial setae absent. Pereopods 5 and 7 coxae facial setae present, pereopod 6 coxa facial setae absent. Pereopods 5–7 bases width length ratios 1: 1.3, 1: 1.1, 1: 1.1, posterior margins smooth, setose.
Pleon. Epimera 1 and 3 bare, epimeron 2 with ventral setae; epimeron 3 posteroventral corner subquadrate. Uropods 1–3 relative lengths 1.0: 0.8: 1.1. Uropod 1 peduncle and inner ramus 0.8 × inner ramus length; inner ramus with 2 robust setae, outer ramus with 1 robust seta. Uropod 2 peduncle 0.6 × inner ramus length, outer ramus 0.9 × inner ramus length; inner and outer rami each with 1 robust seta. Uropod 3 peduncle 1.1 × inner ramus length, outer ramus length 0.9 × inner ramus length; inner and outer rami lined with short marginal setae, inner ramus with 1 robust seta, outer ramus with 2 robust setae. Telson 2.1 × longer than wide, apex weakly tridentate.
Gnathopod 1 basis anterior margin with 1 seta, posterior margin with 2 setae; carpus distal margin with 1 short seta; propodus palm with 2 long and 7 short distal setae; dactylus with 2 proximal setae. Gnathopod 2 basis anterior margin with 4 long setae, posterior margin with 2 setae, posteromedial margin with 1 medium seta; carpus anterior margin dentate.
Named for Dr. Daisuke Ueno, who collected the type specimens of this species. Dr. Ueno has shared valuable specimens and collection locations on Okinawa–jima Island.
In canals of large white ball sponge,
East China Sea: Okinawa–jima Island, Ishigaki–jima Island (both Okinawa), Japan.
Holotype male, 2.5 mm RUMF-ZC-1747, Mizugama, Okinawa–jima Island, Okinawa, reef wall (
Mizugama, Okinawa–jima Island, Okinawa, Japan (
1 specimen, RUMF-ZC-1750, KNW21Aug10; 2 specimens, RUMF-ZC-1751, KNWOkinawa11B; 1 specimen, RUMF-ZC-1752, KNWOkinawa12H; 1 specimen, NSMT-Cr 21882, KNWOkinawa12H; 1 specimen, RUMF-ZC-1753, KNWOkinawa16D; 1 specimen, RUMF-ZC-1754, KNWOkinawa21B; 1 specimen, NSMT-Cr 21883, KNWOkinawa21E; 1 specimen, RUMF-ZC-1755, KNWOkinawa22B; 1 specimen, NSMT-Cr 21884, KNWOkinawa25C; 1 specimen, NSMT-Cr 21885, KNWOkinawa29C; 2 specimens, NSMT-Cr 21886, KNWOkinawa31B; 4 specimens, RUMF-ZC-1756, KNWOkinawa31F; 3 specimens, RUMF-ZC-1757, KNWOkinawa33E; 1 specimen, NSMT-Cr 21887, KNWOkinawa33E; 3 specimens, NSMT-Cr 21888, KNWOkinawa34G; 4 specimens, RUMF-ZC-1758, KNWOkinawa42A; 2 specimens, NSMT-Cr 21889, KNWOkinawa43A; 3 specimens, NSMT-Cr 21890, KNWOkinawa44A; 2 specimens, RUMF-ZC-1759, KNWIriomote2H; 1 specimen, NSMT-Cr 21891, KNWOkinawa51C; 1 specimen, RUMF-ZC-1760, KNWOkinawa53A; 2 specimens, NSMT-Cr 21892, KNWOkinawa53D; 1 specimen, RUMF-ZC-1761, KNWYaku5O; 2 specimens, RUMF-ZC-1762, KNWTokuno4C; 2 specimens, RUMF-ZC-1796, KNWYaku3J; 1 specimen, RUMF-ZC-1797, KNWYaku5I; 2 specimens, RUMF-ZC-1798, KNWOkinawa43D.
Antenna 1 accessory flagellum 1–articulate. Mandibular palp article 3 shorter than article 1. Maxilla 1 palp 1–articulate. Maxilliped outer plate tuberculate. Gnathopod 1 carpus and propodus very slender, chopstick-like; carpus proximal margin with denticles; propodus palm serrate with triangular teeth. Gnathopod 2 propodus with 2 mediofacial setal rows. Pereopods 5–7 bases narrowly expanded.
Head. Anterior margin rounded, anterodistal margin evenly rounded; ventral cephalic keel anterior margin slightly excavate, anteroventral margin subquadrate, ventral margin straight; eyes with more than 10 ommatidia, round. Antenna 1 0.3 × body length, flagellum 5–articulate, peduncle article 1 width less than 2 × article 2, accessory flagellum 1–articulate. Antenna 2 0.2 × body length, slightly shorter than antenna 1, flagellum 5–articulate. Mandibular palp ratio of articles 1–3 1.0: 2.0: 0.4, article 2 with 2 medium distal setae, article 3 with 1 distal seta, incisors weakly dentate; left mandible with 6 raker spines, lacinia mobilis large, strongly toothed; right mandible with 6 raker spines, lacinia mobilis small, strongly dentate. Upper lip asymmetrically lobate, anterior margin setose. Lower lip inner lobes fused, bare; outer lobes with moderate gape, anterior margins setose. Maxilla 1 palp 1–articulate with 4 distal setae; outer plate with 5 distal robust setae. Maxilla 2 inner plate with 5 robust distal setae and 2 robust facial setae; outer plate with 3 robust distal setae and 4 slender distal marginal setae. Maxilliped inner plates distal margin with a v-shaped indentation, with short robust setae; outer plate inner margin tuberculate, reaching 0.1 × palp article 1, with simple marginal setae, facial setae absent; palp article 4 subequal in length with article 3, distally acute.
Pereon. Coxae 1–4 relative widths 1.0: 1.2: 1.2: 1.3. Gnathopod 1 coxa smooth, with tiny marginal setae, anterodistal margin produced, rounded, distal margin straight, posterior margin slightly excavate, facial setae absent; basis distally expanded, anterior margin bare, posterior margin with 2 short setae; ischium bare; carpus linear, distal length 15.8 × width, proximal margin with denticles, distal margin bare; propodus straight, palm serrate with 7 distal triangular teeth and 7 distal setae; dactylus with small proximal notch, reaching 0.2 × propodus length. Gnathopod 2 coxa as long as broad, subequal in size with coxa 3, smooth, with tiny marginal setae, anterior margin expanded, anterodistally rounded, distal and posterior margins straight, facial setae absent; basis distally expanded, anterior margin with 5 medium setae, posterior margin with 1 seta; ischium with 1 posterodistal seta; carpus 0.3 × propodus length, curved, distally truncate, anterior margin dentate; propodus with 2 mediofacial setal rows, primary mediofacial setal row above midline, reaching 0.8 × propodus length, secondary mediofacial setal row with 2 setae, with 1 row of submarginal setae, posterior margin smooth, palm convex with 4 small denticles; dactylus curved, proximal margin smooth with 1 seta, anterior margin distally subacute, reaching 0.8 × propodus length. Pereopod 3 coxa length 1.0 × width, anterodistal corner overriding distal face of coxa 2 and extending below it, smooth, with tiny marginal setae, anterior margin straight, distal margin slightly convex, posterior margin straight, facial setae absent. Pereopod 4 coxa smooth, with tiny marginal setae, anterior margin straight, distal margin evenly rounded, posterior margin tapered, facial setae absent. Pereopods 5–7 coxae facial setae absent; bases width length ratios 1: 1.5, 1: 1.5, 1: 1.7, posterior margins smooth, setose.
Pleon. Epimera 1–2 with ventral setae, epimeron 3 bare; epimeron 3 posteroventral corner rounded. Uropods 1–3 relative lengths 1.0: 0.8: 1.2; inner and outer rami lined with short marginal setae. Uropod 1 peduncle and outer ramus 0.8 × inner ramus length; inner ramus with 6 robust setae and outer ramus with 5 robust setae. Uropod 2 peduncle 0.7 × inner ramus length, outer ramus 0.6 × inner ramus length; inner ramus with 3 robust setae and outer ramus with 4 robust setae. Uropod 3 peduncle 1.2 × inner ramus length, outer ramus 0.9 × inner ramus length; inner ramus with 4 robust setae and outer ramus with 7 robust setae. Telson 2.0 × longer than wide, apex weakly tridentate, almost bidentate.
Gnathopod 1 basis posterior margin with 5 short setae. Gnathopod 2 basis posterior margin with 4 medium setae; ischium with 2 posterior and1 posterodistal seta; carpus distally tapered; propodus secondary mediofacial setal row with 4 setae.
After the Japanese word ‘hashi’, meaning ‘chopsticks’ and referring to the extremely slender carpus and propodus of gnathopod 1. (Pronounced hah-shee.)
East China Sea: Iriomote–jima Island, Okinawa–jima Island (both Okinawa), Tokunoshima Island, Amami–oshima Island, Yakushima Island (all Kagoshima), Japan.
Holotype male, 3.5 mm RUMF-ZC-1763, Kuse, Kakeroma–jima Island reef wall (
Kuse, Kakeroma–jima Island, Amami–oshima Island region, Kagoshima, Japan (
7 specimens, NSMT-Cr 21894, KNWYaku3D; 7 specimens, RUMF-ZC-1765, KNWYaku3D; 1 specimen, RUMF-ZC-1766, KNWYaku5P; 3 specimens, NSMT-Cr 21895 KNWOkinawa44A; 1 specimen, RUMF-ZC-1767, KNWOkinawa44F; 5 specimens, NSMT-Cr 21893, KNWAmami2D; 1 male specimen, RUMF-ZC-1799, KNWAmami2C.
Ventral cephalic keel anterior margin transverse, anteroventral margin quadrate. Eyes oval. Antennae 1 accessory flagellum 1–articulate. Right mandible with small 2–layered lacinia mobilis. Maxilliped inner plates small with serrate robust setae; outer plate tuberculate. Gnathopod 1 coxa anterior margin serrate; carpus robust, proximal margin serrate; propodus palm serrate with triangular teeth. Gnathopod 2 carpus distally truncate; propodus with 2 mediofacial setal rows. Pereopods 5–7 coxae with facial setae; bases posteriorly serrate. Female ventral cephalic keel anteroventral margin serrate; gnathopod 1 basis posterior margin with 6 short setae; gnathopod 2 carpus distally tapered.
Head. Anterior margin rounded, anterodistal margin evenly rounded; ventral cephalic keel anterior margin transverse, anteroventral margin quadrate, ventral margin oblique; eyes with more than 10 ommatidia, oval. Antenna 1 0.4 × body length, flagellum 10+–articulate (broken), peduncle article 1 width less than 2 × article 2, accessory flagellum 1–articulate. Antenna 2 0.3 × body length, slightly shorter than antenna 1, flagellum 6–articulate. Mandibular palp ratio of articles 1–3 1.0: 2.8: 1.0, article 2 with 2 medium distal setae, article 3 with 2 distal setae, incisors strongly dentate; left mandible with 8 raker spines, lacinia mobilis large, strongly toothed; right mandible with 7 raker spines, with small 2–layered lacinia mobilis, strongly dentate. Upper lip asymmetrically lobate, anterior margin setose. Lower lip inner lobes fused, setose; outer lobes with moderate gape, anterior margins setose. Maxilla 1 palp 1–articulate, margins constricted and with 4 distal setae; outer plate with 7 distal robust setae and 6 short marginal setae. Maxilla 2 inner plate with 4 robust distal setae, 2 robust facial setae, and 7 slender marginal setae; outer plate with 3 robust distal setae and 3 slender distal marginal setae. Maxilliped inner plates distal margin with a v-shaped indentation, with short simple and serrate robust setae; outer plate inner margin tuberculate, reaching 0.3 × palp article 1, with simple marginal setae, facial setae absent; palp article 4 subequal in length with article 3, distally acute.
Pereon. Coxae 1–4 relative widths 1.0: 1.5: 1.2: 1.8. Gnathopod 1 coxa smooth, with tiny marginal setae, anterior margin serrate, anterior margin produced, rounded, distal margin straight, posterior margin excavate, facial setae absent; basis linear, anterior margin with 1 short seta, posterior margin with 2 short setae; ischium bare; carpus linear, distal length 7.1 × width, proximal margin serrate, distal margin bare; propodus straight, palm serrate with 10 distal setae and 10 distal triangular teeth; dactylus smooth, reaching 0.1 × propodus length. Gnathopod 2 coxa broader than long, subequal in size with coxa 3, smooth, with tiny marginal setae, anterior margin expanded, anterodistally rounded, distal and posterior margins straight, facial setae absent; basis distally expanded, anterior margin with 10 medium setae, posterior margin with 2 short setae; ischium with 1 posterodistal seta; carpus 0.4 × propodus length, curved, distally truncate, anterior margin dentate; propodus with 2 mediofacial setal rows, primary mediofacial setal row above midline, reaching 0.8 × propodus length, secondary mediofacial setal row with 4 setae, with 1 row of submarginal setae, posterior margin with 5 small robust setae, palm convex with 10 tubercles; dactylus curved, proximal margin smooth with 1 seta, anterior margin distally subacute, reaching 0.5 × propodus length. Pereopod 3 coxa length 1.3 × width, anterodistal corner overriding distal face of coxa 2 and extending below it, smooth, with tiny marginal setae, anterior margin straight, distal margin oblique, posterior margin straight, facial setae absent. Pereopod 4 coxa smooth, with tiny marginal setae, anterior margin produced, distal margin evenly rounded, posterior margin tapered, facial setae absent. Pereopods 5–7 coxae facial setae present; bases width length ratios 1: 1.4, 1: 1.3, 1: 1.2, serrate, setose.
Pleon. Epimera 1–2 with ventral setae, epimeron 3 bare; epimeron 3 posteroventral corner sinuous, rounded. Uropods 1–3 relative lengths 1.0: 0.8: 0.9. Uropod 1 peduncle subequal in length with inner ramus, outer ramus 0.9 × inner ramus length; inner ramus with 6 robust setae and outer ramus with 4 robust setae. Uropod 2 peduncle 0.9 × inner ramus length, outer ramus length 0.6 × inner ramus length; inner ramus with 4 robust setae and outer ramus with 3 robust setae. Uropod 3 peduncle 1.2 × inner ramus length, outer ramus length 0.9 × inner ramus length; inner ramus with 3 robust setae and outer ramus with 5 robust setae. Telson 2.3 × longer than wide, apex strongly tridentate.
Ventral cephalic keel anteroventral margin serrate. Gnathopod 1 basis posterior margin with 6 short setae. Gnathopod 2 basis posterior margin with 1 seta; ischium with 2 distal and 2 posterodistal setae; carpus distally tapered, anterior margin smooth; propodus posterior margin bare.
Named for Sara E. LeCroy, in recognition of her contribution to amphipod taxonomy. Ms LeCroy has been a colleague and friend for the past 7 years and the first author is very grateful for all her support.
In canals of sponges, brown sponge with holes on top only,
East China Sea: Okinawa–jima Island (Okinawa), Amami–oshima Island, Yakushima Island (both Kagoshima), Japan.
Holotype male, 3.0 mm RUMF-ZC-1768, Mizugama, Okinawa–jima Island, Okinawa, reef wall (
Mizugama, Okinawa–jima Island, Okinawa, Japan (
9 specimens, NSMT-Cr 21896, KNWOkinawa69B; 9 specimens, RUMF-ZC-1770, KNWOkinawa69C.
Head anterior margin truncate, anterodistal margin quadrate with cusp. Maxilla 1 palp 1–articulate. Maxilliped outer plate tuberculate with facial setae. Gnathopod 1 basis anterodistal margin with 7 very short, slender setae. Gnathopod 2 carpus elongate, distally tapered; propodus palm with large concavity. Pereopod 7 basis posteriorly serrate. Telson with plumose facial setae.
Head. Anterior margin truncate, anterodistal margin quadrate with cusp; ventral cephalic keel anterior margin transverse, anteroventral margin quadrate, ventral margin distally excavate, rounded; eyes with more than 10 ommatidia, round. Antenna 1 0.3 × body length, flagellum 7–articulate, peduncle article 1 width less than 2 × article 2, accessory flagellum 1–articulate. Antenna 2 0.3 × body length, subequal in length with antenna 1, flagellum 4–articulate. Mandibular palp ratio of articles 1–3 1.0: 3.0: 1.7, article 2 with 2 medium distal setae, article 3 with 2 distal setae, incisors strongly dentate; left mandible with 5 raker spines, lacinia mobilis large, strongly toothed; right mandible with 7 raker spines, lacinia mobilis small, strongly dentate. Upper lip asymmetrically lobate, anterior margin setose. Lower lip inner lobes fused, bare; outer lobes with moderate gape, anterior margins setose. Maxilla 1 palp 1–articulate with 4 distal setae; outer plate with 5 distal robust setae. Maxilla 2 inner plate with 3 robust distal setae and 7 slender marginal setae; outer plate with 3 robust distal setae and 15 slender distal marginal setae. Maxilliped inner plates distal margin with a v-shaped indentation, with short robust setae; outer plate inner margin tuberculate, reaching 0.1 × palp article 1, with simple marginal setae, facial setae present; palp article 4 subequal in length with article 3, distally acute.
Pereon. Coxae 1–4 relative widths 1.0: 1.8: 1.1: 2.1. Gnathopod 1 coxa smooth, with tiny marginal setae, anterodistal margin produced, rounded with cusp, distal margin straight, posterior margin excavate, facial setae absent; basis linear, anterodistal margin with 7 very short, slender setae, posterior margin bare; ischium bare; carpus linear, distal length 13.1 × width, proximal margin serrate, distal margin with 1 short seta; propodus straight, palm with 6 distal triangular teeth and 6 distal setae; dactylus smooth, reaching 0.1 × propodus length. Gnathopod 2 coxa broader than long, subequal in size with coxa 3, smooth, with tiny marginal setae, anterior margin expanded anteriorly, anterodistally rounded, distal margin oblique, posterior margin straight, facial setae absent; basis distally expanded, anterior margin with 5 medium setae, distal margin with 2 setae, posterior margin with 3 setae; ischium with 3 posterior, 2 distal, and 3 posterodistal setae; carpus 0.5 × propodus length, curved, distally tapered, anterior margin smooth; propodus with 1 mediofacial setal row above midline, reaching 0.8 × propodus length, with 2 submarginal setae, posterior margin smooth, palm convex with 6 major tubercles and 1 major concavity; dactylus curved, proximal margin smooth with 1 seta, anterior margin distally acute, reaching 0.5 × propodus length. Pereopod 3 coxa length 1.5 × width, anterodistal corner overriding distal face of coxa 2 and extending below it, smooth, with tiny marginal setae, anterior margin evenly rounded, distal margin oblique, posterior margin straight, facial setae absent. Pereopod 4 coxa smooth, with tiny marginal setae, anterior margin produced, distal margin evenly rounded, posterior margin tapered, facial setae absent. Pereopods 5–7 coxae facial setae absent; bases width length ratios 1: 1.3, 1: 1.3, 1: 1.2, posterior margins setose. Pereopods 5–6 bases posterior margins smooth, pereopod 7 basis posterior margin serrate.
Pleon. Epimera 1 and 3 bare, epimeron 2 with ventral setae; epimeron 3 posteroventral corner rounded. Uropods 1–3 relative lengths 1.0: 0.7: 0.9. Uropod 1 peduncle and outer ramus subequal in length with inner ramus; inner ramus with 5 robust setae and outer ramus with 2 robust setae. Uropod 2 peduncle 0.9 × inner ramus length, outer ramus 0.7 × inner ramus length; inner ramus with 1 robust seta and outer ramus with 2 robust setae. Uropod 3 peduncle 1.6 × inner ramus length, outer ramus 0.9 × inner ramus length; inner ramus with 1 robust seta and outer ramus with 2 robust setae. Telson 2.3 × longer than wide, with plumose facial setae, apex strongly tridentate.
Unknown.
After the Japanese words ‘nagai’, meaning ‘long’, and ‘tekubi’, meaning ‘wrist’ and referring to the elongate carpus on gnathopod 2. (Pronounced na-ga-tay-koo-bee)
In canals of orange encrusting sponge,
East China Sea: Okinawa–jima Island, Okinawa, Japan.
Holotype male, 5.8 mm RUMF-ZC-1771, Channel between Iriomote–jima Island and Hatoma–jima Island, Okinawa, patch reef (
Iriomote Channel between Iriomote–jima and Hatoma–jima Islands (
4 specimens, RUMF-ZC-1773, KNWIriomote2F; 4 specimens, NSMT-Cr 21897, KNWIriomote2F.
Antenna 1 accessory flagellum 1–articulate. Maxilla 1 palp 1–articulate, margins constricted. Maxilliped outer plate with setulate-serrate marginal setae. Gnathopod 1 coxa with 2 mediofacial setae; propodus palm with square-shaped denticles. Gnathopod 2 carpus distally truncate; propodus with long submarginal setae. Pereopod 5 coxa with 2 facial setae. Telson apex with strongly rounded point. Female gnathopod 1 basis anterior margin with 16 short setae, posterior margin with 14 short setae; gnathopod 2 basis anterior margin with 14 short and 2 long curved setae.
Head, anterior margin rounded, anterodistal margin evenly rounded; ventral cephalic keel anterior margin excavate, anteroventral margin subquadrate, ventral margin oblique; eyes with more than 10 ommatidia, round. Antenna 1 0.3 × body length, flagellum 11–articulate, peduncle article 1 width less than 2 × article 2, accessory flagellum 1–articulate. Antenna 2 0.3 × body length, subequal in length with antenna 1, flagellum 7–articulate. Mandibular palp ratio of articles 1–3 1.0: 2.6: 1.1, article 2 with 6–8 long distal setae, article 3 with 2 distal setae, incisors strongly dentate; left mandible with 12 raker spines, lacinia mobilis large, strongly toothed; right mandible with 13 raker spines, lacinia mobilis small, strongly dentate. Upper lip asymmetrically lobate, anterior margin setose. Lower lip inner lobes fused, setose; outer lobes with moderate gape, anterior margins setose. Maxilla 1 palp 1–articulate, margins constricted and with 3 distal setae; outer plate with 7 distal robust setae. Maxilla 2 inner plate with 6 robust distal setae and several slender facial setae; outer plate with 4 robust distal setae and 5 slender distal setae. Maxilliped inner plates distal margin with a v-shaped indentation, with short robust setae; outer plate inner margin smooth, reaching 0.2 × palp article 1, with simple and setulate-serrate marginal setae, facial setae absent; palp article 4 subequal in length with article 3, distally acute.
Pereon. Coxae 1–4 relative widths 1.0: 1.0: 0.8: 1.4. Gnathopod 1 coxa smooth, with tiny marginal setae, anterodistal margin produced, subquadrate, distal margin straight, posterior margin excavate, 2 mediofacial setae present; basis proximally widened, anterior margin with 7 short setae, posterior margin with 6 short setae; ischium bare; carpus linear, distal length 13.1 × width, proximal margin smooth, distal margin bare; propodus straight, palm with square-shaped denticles with 6 large and 20 small proximal setae; dactylus smooth, with 2 distal setae, reaching 0.5 × propodus length. Gnathopod 2 coxa as long as broad, subequal in size with coxa 3, smooth, with tiny marginal setae, anterior margin expanded anteriorly, anterodistally rounded, distal and posterior margins rounded, facial setae absent; basis slightly posteriorly expanded, anterior margin with 7 short and 2 long curved setae, posterior margin with 1 posterodistal seta, distal margin with 2 setae; ischium with 3 short posterior, 2 long distal, and 5 short posterodistal setae; carpus 0.4 × propodus length, curved, distally truncate, anterior margin smooth; propodus with 1 mediofacial setal row displaced to midline, reaching 0.8 × propodus length, with 1 row of short and long submarginal setae, posterior margin smooth, palmar corner pronounced, palm convex with small tubercles; dactylus curved, proximal margin smooth with 2 setae, anterior margin distally acute, reaching 0.6 × propodus length. Pereopod 3 coxa length 1.4 × width, anterodistal corner overriding distal face of coxa 2 and extending below it, smooth, with tiny marginal setae, anterior margin expanded, distal margin slightly convex, posterior margin tapered, facial setae absent. Pereopod 4 coxa smooth, with tiny marginal setae, anterior margin produced, distal margin evenly rounded, posterior margin excavate, facial setae absent. Pereopod 5 coxa with 2 facial setae. Pereopods 6–7 coxae facial setae absent. Pereopods 5–7 bases width length ratios 1: 1.2, 1: 1.2, 1: 1.0, posterior margins smooth, setose.
Pleon. Epimera 1–2 with ventral setae, epimeron 3 bare; epimeron 3 posteroventral corner subquadrate. Uropods 1–3 relative lengths 1.0: 0.7: 1.0. Uropod 1 peduncle 0.8 × inner ramus length, outer ramus 0.9 × inner ramus length; inner ramus with 4 robust setae and outer ramus with 6 robust setae. Uropod 2 peduncle subequal in length with inner ramus, outer ramus 0.8 × inner ramus length; inner ramus with 5 robust setae and outer ramus with 3 robust setae. Uropod 3 peduncle 1.2 × inner ramus length, outer ramus 0.8 × inner ramus length; inner and outer rami lined with short marginal setae; inner ramus with 4 robust setae and outer ramus with 5 robust setae. Telson 2.3 × longer than wide, apex with strongly rounded point.
Gnathopod 1 basis anterior margin with 16 short setae, posterior margin with 14 short setae; ischium with 3 short posterior setae. Gnathopod 2 basis anterior margin with 14 short and 2 long curved setae; ischium with 3 distal and 6 posterodistal setae; carpus slightly less truncate than in the male.
After the Japanese word ‘nurunuru’, meaning ‘slimy’ and referring to the host sponge. (Pronounced new-rue-new-rue)
In canals of
East China Sea: Iriomote–jima Island, Okinawa, Japan.
Holotype male, 3.3 mm RUMF-ZC-1774, Kita–nakase, Oura–wan Bay, Okinawa–jima Island, Okinawa, patch reef (
Oura–wan Bay, Okinawa–jima Island, Okinawa, Japan (26°32'40–43"N, 128°02'56"–03'36"E).
1 specimen, RUMF-ZC-1776, KNWOkinawa39H; 1 specimen, NSMT-Cr 21898, KNWOkinawa39L; 1 specimen, RUMF-ZC-1777, KNWOkinawa37C; 2 specimens, NSMT-Cr 21899, KNWOkinawa37N.
Head anterior margin truncate, anterodistal margin quadrate. Ventral cephalic keel anteroventral margin with anteriorly projecting cusp. Right mandible lacinia mobilis cleft. Upper lip distal margin with row of short setae. Maxilla 1 palp 1–articulate, proximal margin serrate. Maxilliped outer plate tuberculate. Gnathopod 1 basis posterior margin with 6 short setae; propodus palm serrate; dactylus reaching 0.1 × propodus length. Gnathopod 2 carpus distally truncate; propodus with 2 mediofacial setal rows. Uropod 3 peduncle 1.2 × inner ramus length. Telson apex bidentate.
Head. Anterior margin truncate, anterodistal margin quadrate; ventral cephalic keel anterior margin oblique, anteroventral margin with anteriorly projecting cusp, ventral margin convex; eyes with more than 10 ommatidia, round. Antenna 1 0.3 × body length, flagellum 8–articulate, peduncle article 1 width less than 2 × article 2, accessory flagellum absent. Antenna 2 0.3 × body length, subequal in length with antenna 1, flagellum 5–articulate. Mandibular palp ratio of articles 1–3 1.0: 2.4: 1.6, article 2 with 3 medium distal setae, article 3 with 2 distal setae, incisors weakly dentate; left mandible with 9 raker spines, lacinia mobilis large, strongly toothed; right mandible with 7 raker spines, lacinia mobilis small, strongly dentate, cleft. Upper lip asymmetrically lobate, anterior margin setose, distal margin with row of short setae. Lower lip inner lobes fused, setose; outer lobes with moderate gape, anterior margins setose. Maxilla 1 palp 1–articulate with 4 distal setae, proximal margin serrate; outer plate with 4 distal robust setae and 4 distal setae. Maxilla 2 inner plate with 3 robust distal setae and 4 slender marginal setae; outer plate with 2 robust and 2 slender distal setae and 6 slender distal marginal setae. Maxilliped inner plates distal margin with a v-shaped indentation, with short robust setae; outer plate inner margin tuberculate, reaching 0.1 × palp article 1, with simple marginal setae, facial setae present; palp article 4 subequal in length with article 3, distally acute.
Pereon. Coxae 1–4 relative widths 1.0: 1.2: 0.9: 1.7. Gnathopod 1 coxa smooth, with tiny marginal setae, anterior margin produced, rounded, distal margin straight, posterior margin excavate, facial setae absent; basis distally expanded, anterior margin bare, posterior margin with 6 short setae; ischium bare; carpus linear, distal length 13.6 × width, proximal margin smooth, distal margin bare; propodus straight, palm serrate with 9 distal setae; dactylus smooth, reaching 0.1 × propodus length. Gnathopod 2 coxa as long as broad, subequal in size with coxa 3, smooth, with tiny marginal setae, anterior margin straight, anterodistally rounded, distal margin evenly rounded, posterior margin straight, facial setae absent; basis distally expanded, anterior margin with 9 setae, posterior margin with 4 setae; ischium with 1 posterodistal seta; carpus 0.4 × propodus length, curved, distally truncate, anterior margin dentate; propodus with 2 mediofacial setal rows, primary mediofacial setal row above midline, reaching 0.8 × propodus length, secondary mediofacial setal row with 2 setae, with 1 row of submarginal setae, posterior margin smooth, palm convex, dentate; dactylus curved, proximal margin smooth with 1 seta, anterior margin distally acute, reaching 0.6 × propodus length. Pereopod 3 coxa length 1.4 × width, anterodistal corner overriding distal face of coxa 2 and extending below it, smooth, with tiny marginal setae, anterior margin straight, distal margin slightly convex, posterior margin straight, facial setae absent. Pereopod 4 coxa smooth, with tiny marginal setae, anterior margin produced, distal margin evenly rounded, posterior margin tapered, facial setae absent. Pereopods 5–7 coxae facial setae absent. Pereopods 5–7 bases width length ratios 1: 1.4, 1: 1.2, 1: 1.1; posterior margins smooth, setose.
Pleon. Epimera 1–2 with ventral setae, epimeron 3 bare; epimeron 3 posteroventral corner rounded. Uropods 1–3 relative lengths 1.0: 0.8: 1.1; outer rami lined with short marginal setae. Uropod 1 peduncle and outer ramus subequal in length with inner ramus; inner ramus with 2 robust setae; outer ramus without robust setae. Uropod 2 peduncle length 0.8 × inner ramus, outer ramus length 0.6 × inner ramus; inner ramus with 4 robust setae; outer ramus with 3 robust setae. Uropod 3 peduncle length 1.2 × inner ramus, outer ramus subequal in length with inner ramus; inner and outer rami lined with short marginal setae, each with 4 robust setae. Telson 2.7 × longer than wide, apex bidentate.
Gnathopod 2 ischium with posterior and posterodistal setae; carpus distally tapered, anterior margin smooth; propodus secondary mediofacial setal row with 4 setae.
After the Japanese place name ‘Oura’, meaning ‘large inlet’ and referring to the type locality. (Pronounced oh-ooh-ra)
East China Sea: Okinawa–jima Island, Okinawa, Japan.
Holotype male, 4.2 mm RUMF-ZC-1778, Yoshida, Yakushima Island, Kagoshima, patch reef (
Yoshida, Yakushima Island, Kagoshima, Japan (
2 specimens, RUMF-ZC-1780, KNWYaku5M; 1 specimen, NSMT-Cr 21900, KNWOkinawa35A; 1 specimen, RUMF-ZC-1781, KNWOkinawa36E; 1 specimen, RUMF-ZC-1782, KNWYaku1F; 1 specimen, NSMT-Cr 21901, KNWOkinawa51D; 1 specimen, RUMF-ZC-1783, KNWYaku1G; 1 specimen, KNWOkinawa55E.
Ventral cephalic keel anteroventral margin quadrate with large projection. Antenna 1 accessory flagellum 1–articulate. Mandibular palp article 2 with 11 long distal setae; article 2 with facial setae and 1 distal seta. Gnathopod 2 basis anterior margin with 7 long curved setae; carpus with setulate-serrate marginal setae; propodus with 3 mediofacial setal rows. Pereopod 7 basis posterior margin serrate. Female gnathopod 1 carpus elongate; gnathopod 2 basis anterior margin with 22 long curved setae, distal margin with 4 long curved setae; ischium with 3 long and 2 short distal setae, carpus distally truncate.
Head. Anterior margin rounded, anterodistal margin evenly rounded; ventral cephalic keel anterior margin excavate, anteroventral margin quadrate with projection, ventral margin convex; eyes with more than 10 ommatidia, round. Antenna 1 0.3 × body length, flagellum 10–articulate, peduncle article 1 width less than 2 × article 2, accessory flagellum 1–articulate. Antenna 2 0.3 × body length, subequal in length with antenna 1, flagellum 8–articulate. Mandibular palp ratio of articles 1–3 1.0: 3.4: 2.0, article 2 with 11 long distal setae, article 3 with facial setae and 1 distal seta, incisors strongly dentate; left mandible with 10 raker spines, lacinia mobilis large, strongly toothed; right mandible with 11 raker spines, lacinia mobilis small, strongly dentate. Upper lip asymmetrically lobate, anterior margin setose. Lower lip inner lobes fused, bare; outer lobes with moderate gape, anterior margins setose. Maxilla 1 palp 2–articulate with 4 distal setae; outer plate with 9 distal robust setae. Maxilla 2 inner plate with 5 robust distal setae, 1 robust facial seta, and several slender facial setae; outer plate with 3 robust distal setae and 13 slender distal marginal setae. Maxilliped inner plates distal margin with a v-shaped indentation, with short robust setae; outer plate inner margin smooth, reaching 0.1 × palp article 1, with simple marginal setae, facial setae absent; palp article 4 subequal in length with article 3, distally acute.
Pereon. Coxae 1–4 relative widths 1.0: 1.2: 0.9: 1.6. Gnathopod 1 coxa smooth, bare, anterodistal margin produced, subquadrate, distal margin straight, posterior margin excavate, facial setae absent; basis distally expanded, anterior margin with 5 medium setae, posterior margin bare; ischium bare; carpus linear, distal length 11.2 × width, proximal margin smooth, distal margin with 2 short setae; propodus straight, palm dentate with 7 robust and 12 distal setae; dactylus smooth, reaching 0.4 × propodus length. Gnathopod 2 coxa broader than long, subequal in size with coxae 3, smooth, bare, anterior margin straight, anterodistally rounded, distal and posterior margins straight, facial setae absent; basis slightly posteriorly expanded, anterior margin with 7 long curved setae, distal margin with 2 long setae, posterior margin bare; ischium with 2 distal setae; carpus 0.3 × propodus length, curved, distally tapered, anterior margin smooth, with setulate-serrate marginal setae; propodus with 1 mediofacial setal row above midline, reaching 0.8 × propodus length, with 3 rows of submarginal setae, posterior margin smooth, palm convex with 2 large and several small tubercles; dactylus curved, proximal margin smooth with 2 setae, anterior margin distally acute, reaching 0.6 × propodus length. Pereopod 3 coxa length 1.3 × width, anterodistal corner overriding distal face of coxa 2 and extending below it, smooth, bare, anterior margin straight, distal margin oblique, posterior margin straight, facial setae absent. Pereopod 4 coxa smooth, bare, anterior margin produced, distal margin evenly rounded, posterior margin excavate, facial setae absent. Pereopods 5–7 coxae facial setae absent, bases width length ratios 1: 1.3, 1: 1.2, 1: 1.2, posterior margins bare; pereopods 5–6 bases posterior margins smooth, pereopod 7 basis posterior margin serrate.
Pleon. Epimera 1–2 with ventral setae, epimeron 3 bare; epimeron 3 posteroventral corner subquadrate. Uropods 1–2 relative lengths 1.0: 0.9. Uropod 1 peduncle 0.7 × inner ramus length, outer ramus 0.8 × inner ramus length; inner ramus with 4 robust setae on each margin; outer ramus with 4 robust setae. Uropod 2 peduncle 0.8 × inner ramus length, outer ramus 0.7 × inner ramus length; inner ramus with 4 robust setae; outer ramus with 3 robust setae. Uropod 3 missing. Telson 2.3 × longer than wide, with 2 simple facial setae, apex weakly tridentate.
Gnathopod 1 carpus length 10.8 × width; basis anterior margin with 8 long setae. Gnathopod 2 basis distally expanded, anterior margin with 22 long curved setae, distal margin with 4 long curved setae; ischium with 3 long and 2 short distal setae; carpus distally truncate, anterior margin dentate; propodus palm with 1 row of submarginal setae.
After the Japanese word ‘togatta’, meaning ‘sharp’ and referring to the sharply pointed projection on the ventral cephalic keel. (Pronounced toe-ga-ta)
In canals of hard brown sponge, yellow inside with groups of small holes on top, ?
East China Sea: Okinawa–jima Island (Okinawa), Yakushima Island (Kagoshima), Japan.
Holotype male, 3.3 mm RUMF-ZC-1784, Manza, Okinawa–jima Island, Okinawa, reef wall (
Manza, Okinawa–jima Island, Okinawa, Japan (
4 specimens, RUMF-ZC-1786, KNWOkinawa22C; 5 specimens, NSMT-Cr 21902, KNWOkinawa23D; 2 specimens, RUMF-ZC-1787, KNWOkinawa23E; 1 specimen, NSMT-Cr 21903, KNWOkinawa25E; 4 specimens, RUMF-ZC-1788, KNWOkinawa27D; 6 specimens, NSMT-Cr 21904, KNWOkinawa29K; 6 specimens, RUMF-ZC-1789, KNWOkinawa30E; 1 specimen, RUMF-ZC-1790, KNWOkinawa33G; 12 specimens, NSMT-Cr 21905, KNWOkinawa39J.
Head anterodistal margin concave. Mandibular palp article 3 shorter than article 1; left mandible with 5 robust marginal setae. Maxilla 1 palp 1–articulate. Maxilliped inner plates with facial setae. Gnathopod 1 basis distally expanded, posterior margin with 5 short proximal setae; carpus robust; propodus curved, palm smooth with 22 short distal setae; dactylus reaching 0.2 × propodus length. Gnathopod 2 carpus distally truncate, spoon-like, with setulate-serrate setae; propodus with 3 mediofacial setal rows; dactylus elongate. Pereopods 5–6 coxae with facial setae; epimeron 3 posteroventral corner sinuous.
Head. Anterior margin transverse, anterodistal margin concave; ventral cephalic keel anterior margin transverse, anteroventral margin rounded, ventral margin excavate; eyes with more than 10 ommatidia, round. Antenna 1 0.4 × body length, flagellum 10–articulate, peduncle article 1 width less than 2 × article 2, accessory flagellum 1–articulate. Antenna 2 0.3 × body length, slightly shorter than antenna 1, flagellum 6–articulate. Mandibular palp ratio of articles 1–3 1.0: 2.6: 0.8, article 2 with 2 medium distal setae, article 3 with 1 distal seta, incisors weakly dentate; left mandible with 1 row of 5 and 1 row of 4 raker spines, with 5 robust marginal setae, lacinia mobilis large, strongly toothed; right mandible with 9 raker spines, lacinia mobilis small, weakly dentate. Upper lip asymmetrically lobate, anterior margin setose. Lower lip inner lobes fused, bare; outer lobes with moderate gape, anterior margins setose. Maxilla 1 palp 1–articulate with 4 distal setae; outer plate with 6 distal robust setae and 6 distal setae. Maxilla 2 inner plate with 3 robust distal and 3 robust marginal setae; outer plate with 4 robust distal setae and 4 sets of 2 slender distal marginal setae. Maxilliped inner plates distal margin with a v-shaped indentation, with short robust setae, facial setae present; outer plate inner margin smooth, reaching 0.3 × palp article 1, with simple marginal setae, facial setae absent; palp article 4 subequal in length with article 3, distally acute.
Pereon. Coxae 1–4 relative widths 1.0: 1.4: 1.1: 1.2. Gnathopod 1 coxa smooth, with tiny marginal setae, anterodistal margin produced, rounded, distal margin rounded, posterior margin excavate, facial setae absent; basis distally expanded, anterior margin with 1 short seta, anterodistal margin with several short slender setae, posterior margin with 5 setae; ischium bare; carpus linear, distal length 5.3 × width, proximal margin smooth, distal margin with 5 short setae; propodus curved, palm smooth with 22 distal setae; dactylus smooth, reaching 0.2 × propodus length. Gnathopod 2 coxa as long as broad, subequal in size with coxa 3, smooth, with tiny marginal setae, anterior margin straight, anterodistally subquadrate, distal and posterior margins straight, facial setae absent; basis distally expanded, anterior margin with 9 short setae, posterior margin with 1 short seta; ischium bare; carpus 0.2 × propodus length, curved, distally truncate, spoon-like, anterior margin smooth with setulate-serrate setae; propodus with 3 mediofacial setal rows, primary mediofacial setal row above midline, reaching 0.9 × propodus length, secondary mediofacial setal row with 9 setae, tertiary mediofacial setal row with 4 setae, posterior margin smooth, palmar corner pronounced, palm convex with 4 major tubercles; dactylus curved, proximal margin smooth with 2 setae, anterior margin distally subacute, reaching 0.7 × propodus length. Pereopod 3 coxa length 1.5 × width, anterodistal corner overriding distal face of coxa 2 and extending below it, smooth, with tiny marginal setae, anterior margin straight, distal margin slightly convex, posterior margin straight, facial setae absent. Pereopod 4 coxa smooth, with tiny marginal setae, anterior margin straight, distal margin produced, posterior margin excavate, facial setae absent. Pereopods 5–6 coxae facial setae present. Pereopod 7 coxa facial setae absent. Pereopods 5–7 bases width length ratios 1: 1.3, 1: 1.2, 1: 1.1, posterior margins smooth, setose.
Pleon. Epimera 1–2 with ventral setae, epimeron 3 bare; epimeron 3 posteroventral corner sinuous, rounded. Uropods 1–3 relative lengths 1.0: 0.7: 1.0. Uropod 1 peduncle subequal in length with inner ramus, outer ramus 0.8 × inner ramus length; inner ramus with 3 robust setae; outer ramus with 4 robust setae. Uropod 2 peduncle and outer ramus 0,7 × inner ramus length; inner and outer rami each with 3 robust setae. Uropod 3 peduncle and outer ramus subequal in length with inner ramus; inner ramus with 3 robust setae; outer ramus with 2 robust setae. Telson 2.5 × longer than wide, apex weakly tridentate.
Gnathopod 2 basis linear, posterior margin bare; ischium with 5 posterodistal setae; carpus 0.4 × propodus length, distally tapered.
After the Japanese word ‘toribe’, meaning ‘ladle’ and referring to the spoon-like carpus on gnathopod 2. (Pronounced toe-ree-bay)
In canals of green hard branching sponge, ?
East China Sea: Okinawa–jima Island (Okinawa), Yakushima Island (Kagoshima), Japan.
Holotype male, 3.2 mm, RUMF-ZC-1791, Zanpa Cape, Okinawa–jima Island, Okinawa, reef wall (
Cape Zanpa, Okinawa–jima Island, Okinawa, Japan (
12 specimens, RUMF-ZC-1793, KNWOkinawa34A; 13 specimens, NSMT-Cr 21906, KNWOkinawa34A; 3 specimens, RUMF-ZC-1794, KNWOkinawa34B; 2 specimens, NSMT-Cr 21907, KNWOkinawa34B.
Eyes rectangular. Antenna 1 0.6 × body length, peduncle article 1 width greater than 2 × article 2. Gnathopod 1 coxa about ½ as wide as coxa 2; basis proximally inflated, elongate; carpus and propodus elongate. Gnathopod 2 basis posterior margin with 2 long setae; ischium with 5 long posterodistal setae; propodus with 1 row of robust submarginal setae. Pereopod 5 coxa with facial setae; pereopods 5–7 bases very narrowly expanded. Uropod 3 peduncle 1.5 × inner ramus length. Telson apex truncate.
Head. Anterior margin excavate, anterodistal margin subquadrate; ventral cephalic keel anterior margin excavate, anteroventral margin rounded, ventral margin straight; eyes with more than 10 ommatidia, rectangular. Antenna 1 0.6 × body length, flagellum 6–articulate, peduncle article 1 width greater than 2 × article 2, accessory flagellum absent. Antenna 2 0.5 × body length, slightly shorter than antenna 1, flagellum 3–articulate. Mandibular palp ratio of articles 1–3 1.0: 2.0: 1.3, article 2 with 4–5 short distal setae, article 3 with 2 distal setae, incisors strongly dentate; left mandible with 8 raker spines, lacinia mobilis large, strongly toothed; right mandible with 12 raker spines, lacinia mobilis small, strongly dentate. Upper lip asymmetrically lobate, anterior margin setose. Lower lip inner lobes fused, bare; outer lobes with large gape, anterior margins setose. Maxilla 1 palp 2–articulate with 4 distal setae; outer plate with 4 distal robust setae and 7 distal setae. Maxilla 2 inner plate with 5 robust distal setae and 1 slender facial seta; outer plate with 4 robust distal setae, 7 distal and 5 proximal slender marginal setae. Maxilliped inner plates fused, distal margin with a v-shaped indentation, with short robust setae; outer plate inner margin tuberculate, reaching 0.1 × palp article 1, with simple marginal setae, facial setae present; palp article 4 subequal in length with article 3, distally acute.
Pereon. Coxae 1–4 relative widths 1.0: 1.9: 1.7: 1.7. Gnathopod 1 coxa smooth, with tiny marginal setae, anterior margin straight, anterodistal margin subquadrate, distal margin straight, posterior margin excavate, facial setae absent; basis proximally inflated, anterior margin with 4 setae, posterior margin with 2 setae; ischium bare; carpus linear, distal length 14.1 × width, proximal margin with denticles, distal margin bare; propodus curved, palm serrate with 13 distal setae; dactylus smooth, reaching 0.2 × propodus length. Gnathopod 2 coxa longer than broad, subequal in size with coxa 3, smooth, with tiny marginal setae, anterodistally rounded, distal margin straight, posterior margin straight, facial setae absent; basis linear, anterior margin with 5 short setae, posterior margin with 2 long setae; ischium with 5 long posterodistal setae; carpus 0.4 × propodus length, straight, distally tapered, anterior margin smooth; propodus with 1 mediofacial setal row displaced to midline, reaching 0.6 × propodus length, with 1 row of robust submarginal setae, posterior margin smooth, palm convex with many small tubercles; dactylus curved, proximal margin smooth, bare, anterior margin distally subacute, reaching 0.6 × propodus length. Pereopod 3 coxa length 0.8 × width, anterodistal corner overriding distal face of coxa 2, not extending below it, smooth, with tiny marginal setae, anterior margin evenly rounded, distal and posterior margins straight, facial setae absent. Pereopod 4 coxa smooth, with tiny marginal setae, anterior margin straight, distal margin evenly rounded, posterior margin straight, facial setae absent. Pereopod 5 coxa facial setae present, pereopods 6–7 coxae facial setae absent. Pereopods 5–7 bases width length ratios 1: 1.8, 1: 1.9, 1: 1.7, posterior margins smooth, setose.
Pleon. Epimera 1 and 3 bare, epimeron 2 with ventral setae; epimeron 3 posteroventral corner rounded. Uropods 1–3 relative lengths 1.0: 0.7: 0.8. Uropod 1 peduncle and outer ramus subequal in length with inner ramus; inner ramus with 1 robust seta; outer ramus lined with short marginal setae, with 5 robust setae. Uropod 2 peduncle 0.9 × inner ramus length, outer ramus 0.8 × inner ramus length; inner ramus with 2 robust setae; outer ramus lined with short marginal setae, with 2 robust setae. Uropod 3 peduncle 1.5 × inner ramus length, outer ramus subequal in length with inner ramus; inner ramus lined with short marginal setae, without robust setae; outer ramus with 3 robust setae. Telson 2.0 × longer than wide, apex truncate.
Antenna 1 0.2 × body length. Antenna 2 0.3 × body length, subequal in length with antenna 1. Gnathopod 1 basis proximally wider than in male, posterior margin with 11 long setae. Gnathopod 2 basis anterior margin with 10 short setae.
After the Japanese place name ‘Zanpa’, meaning ‘wave slicing’ and referring to the type locality.
In canals of large white ball sponge,
Color plate of new leucothoid amphipod species.
Color plate of new leucothoid amphipod species and sponge hosts.
Color plate of sponge hosts.
East China Sea: Okinawa–jima Island, Okinawa, Japan.
Sponge hosts for
1 | Antenna 1 length greater than 0.5 × body length (males), peduncle article 1 width greater than 2 × article 2; eyes rectangular; coxa 1 about ½ width of coxa 2, telson apex truncate |
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– | Antenna 1 length less than 0.5 × body length, peduncle article 1 width less than 2 × article 2; eyes round or oval; coxa 1 subequal to or slightly smaller than coxa 2, telson apex tridentate, bidentate, or with strong point (rounded or sharp) | 2 |
2 | Gnathopod 1 propodus curved | 3 |
– | Gnathopod 1 propodus straight | 4 |
3 | Gnathopod 1 palm without ornamentation; gnathopod 2 carpus distally truncate, spoon-like (male) |
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– | Gnathopod 1 palm dentate; gnathopod 2 carpus distally tapered | |
4 | Maxilliped outer plate tuberculate; gnathopod 1 dactylus 0.2 or less × propodus length | 5 |
– | Maxilliped outer plate smooth; gnathopod 1 dactylus length greater than 0.2 × propodus length | 8 |
5 | Ventral cephalic keel anterior margin oblique, anteroventral margin with projection; gnathopod 1 basis distally expanded, propodus palm without large triangular teeth, dactylus reaching less than 0.1 × propodus length; telson apex bidentate |
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– | Ventral cephalic keel anterior margin transverse, anteroventral margin quadrate; gnathopod 1 basis linear, propodus palm with large triangular teeth, dactylus reaching 0.1–0.2 × propodus length; telson apex tridentate | 6 |
6 | Head anterior margin truncate, anterodistal margin quadrate with cusp; maxilliped outer plate with facial setae; gnathopod 1 basis posterior margin bare, distal margin setose; gnathopod 2 carpus distally tapered, propodus with 1 mediofacial setal row |
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– | Head anterior margin round, anterodistal margin round; maxilliped outer plate without facial setae; gnathopod 1 basis posterior margin setose, distal margin bare; gnathopod 2 carpus distally truncate, propodus with 2 mediofacial setal rows | 7 |
7 | Antenna 1 accessory flagellum 1–articulate; mandibular palp article 3 shorter than article 1 and with 1 distal seta; maxilla 1 palp 1–articulate; gnathopod 1 basis anterior margin bare, carpus slender; pereopods 5–6 coxae without facial setae, pereopods 5–7 bases narrowly expanded |
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– | Antenna 1 accessory flagellum absent; mandibular palp article 3 subequal in length with article 1 and with 2 distal setae; maxilla 1 palp 2–articulate; gnathopod 1 basis anterior margin setose, carpus robust; pereopods 5–6 coxae with facial setae, pereopods 5–7 bases broadly expanded |
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8 | Head anterodistal margin quadrate; gnathopod 2 propodus with 2 mediofacial setal rows; pereopods 5–7 bases narrowly expanded (length greater than 1.4 × width) |
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– | Head anterodistal margin rounded or subquadrate; gnathopod 2 propodus with 1 mediofacial setal row; pereopods 5–7 bases broadly expanded (length 1.4 × width or less) | 9 |
9 | Ventral cephalic keel anteroventral margin with strong anterior projection; antenna 1 accessory flagellum 1–articulate; mandibular palp article 3 with 1 distal seta; gnathopod 2 propodus mediofacial setal row above midline; pereopod 7 basis posterior margin serrate |
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– | Ventral cephalic keel anteroventral margin subquadrate or quadrate with small projection; antenna 1 accessory flagellum absent; mandibular palp article 3 with 2 distal setae; gnathopod 2 propodus mediofacial setal row displaced to midline; pereopod 7 basis posterior margin smooth | 10 |
10 | Ventral cephalic keel anteroventral margin quadrate with small projection; maxilliped outer plate with facial setae; coxa 1 anterior margin serrate; gnathopod 1 ischium with posterior setae; |
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– | Ventral cephalic keel anteroventral margin subquadrate; maxilliped outer plate without facial setae; coxa 1 anterior margin smooth; gnathopod 1 ischium bare | 11 |
11 | Mandibular palp article 2 with 15 distal setae; gnathopod 1 coxa anterior margin serrate, basis posterior margin bare; gnathopod 2 basis anterior margin with 10 setae, carpus reaching less than 0.4 × propodus length, propodus palm with large projections; pereopod 5 coxa without facial seta | |
– | Mandibular palp article 2 with less than 10 distal setae; gnathopod 1 coxa anterior margin smooth, basis posterior margin setose; gnathopod 2 basis anterior margin with less than 10 setae, carpus reaching greater than 0.4 × propodus length, propodus palm with small projections; pereopod 5 coxa with facial setae | 12 |
12 | Antenna 1 flagellum 11–articulate; maxilla 1 palp 1–articulate, margins constricted; maxilliped inner plates with simple setae; gnathopod 1 carpus proximal margin smooth; gnathopod 2 basis posterior margin bare, carpus distally truncate; telson apex with strongly rounded point |
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– | Antenna 1 flagellum 6–articulate; maxilla 1 palp 1–articulate; maxilliped inner plates with simple and serrate setae; gnathopod 1 carpus proximal margin dentate; gnathopod 2 basis posterior margin setose, carpus distally tapered; telson apex tridentate |
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Four of the
The currently recognized biogeographic boundaries of the Ryukyu Archipelago (
Restricted distributional patterns were observed in
The host data collected here are invaluable in understanding the ecology of these amphipods. Sponges are often a preferred habitat for leucothoid amphipods, functioning as a food resource and as protection from predators (
Most of the species reported here were collected from 1–4 sponge host species and from coral rubble. Presumably, these amphipods are inhabiting sponges in the crevices of the coral rubble. Perhaps the ephemeral nature of the sponges is also forcing the amphipods to adapt to new and available hosts, which may explain the higher number of species found in the genus
The very high diversity of new leucothoid species discovered in the Ryukyu Archipelago to date supports the theory of
The authors would like to thank Nicole de Voogd (Naturalis) for her help with identifying sponges. Thanks also go to Nathan White for his tremendous support and assistance with all research efforts in the Ryukyu Archipelago and to Dr. Masami Obuchi for his logistical support and collection assistance. Additional support in many forms has been provided by members of the MISE Laboratory at the University of the Ryukyus. The Rising Star Program at the University of the Ryukyus provided laboratory space and logistical support. Reviews from Traudl Krapp and Alan Myers significantly improved the manuscript. Funding was provided by a Japanese Society for the Promotion of Science (JSPS) postdoctoral fellowship awarded to the first author (#P10711). The second author was supported in part by the International Research Hub Project for Climate Change and Coral Reef/Island Dynamics at the University of the Ryukyus.