Research Article |
Corresponding author: Rony Huys ( rjh@nhm.ac.uk ) Academic editor: Kai Horst George
© 2018 Rony Huys, Jimin Lee.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Huys R, Lee J (2018) Philippiphonte aspidosoma gen. et sp. n., a radically divergent member of the Laophontidae from shell gravel in the East Sea, South Korea, including a review of Folioquinpes Fiers & Rutledge, 1990 (Copepoda, Harpacticoida). ZooKeys 775: 15-46. https://doi.org/10.3897/zookeys.775.26404
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The primarily marine subtidal family Laophontidae not only contains more valid genera than any other family in the Harpacticoida, it is also one of the most speciose ones in the order, currently accommodating 327 species and subspecies. Based on published records, 25 laophontid species in 12 genera have so far been reported from Korean waters. Here both sexes of a new genus and species of Laophontidae are described, collected from shell gravel off Dokdo Island in the East Sea. Philippiphonte aspidosoma gen. et sp. n. displays a radically divergent morphology, including an extreme dorsoventrally depressed body shape which is reminiscent of members of the family Porcellidiidae. The convergent evolution of dorsoventrally flattened body plans in the Harpacticoida is briefly discussed.
The distribution and habitat preference of laophontid species recorded from the Korean peninsula are summarised. The authenticity of the Korean record of Folioquinpes mangalis Fiers & Rutledge, 1990 from washings of invertebrates and intertidal stones from Jeju Island is reassessed in the light of a discussion of the genus. Folioquinpes pseudomangalis sp. n. and F. indicus sp. n. are proposed as new species for Folioquinpes mangalis Fiers & Rutledge, 1990 sensu
Copepoda , Dokdo island, Folioquinpes indicus sp. n., F. pseudomangalis sp. n., key to species, Laophontidae , shell gravel
The Laophontidae is one of the most speciose families in the Harpacticoida, currently accommodating 327 species and subspecies and containing more valid genera (74!) than any other family in the order. Members of the family can be found in tropical to polar waters and typically occur subtidally in fine to coarse-grained sandy sediments at shallow depths. Laophontids have also radiated into a wide range of other habitats, including saltmarshes and intertidal mudflats (
Based on published records, 25 laophontid species in 12 genera have so far been reported from Korean waters. The species listed in an unpublished PhD dissertation (
Both sexes of a new species were collected from shell gravel off Dokdo Island in the East Sea. The new species displays a radically divergent morphology and cannot be accommodated in any of the currently recognised genera. It is here fixed as the type species of a new genus, Philippiphonte gen. n., and described in detail. The authenticity of the Korean record of Folioquinpes mangalis from washings of invertebrates and intertidal stones from Jeju Island is reassessed in the light of a review of the genus Folioquinpes Fiers & Rutledge, 1990.
Samples were collected by SCUBA diving by scooping the upper ~ 5 cm of sublittoral sediments around Dokdo Island, East Sea (Sea of Japan), South Korea (Figure
The descriptive terminology is adopted from
Type specimens were deposited in the National Biological Resources Center (NIBR), Incheon, Republic of Korea. Additional material was stored in the Korea Institute of Ocean Science and Technology (KIOST), Busan, Korea.
Laophontidae. Body extremely dorsoventrally flattened, porcellidiid-like. Distinct sexual dimorphism in size, urosomal segmentation, antennule, P3 endopod, P5, and P6. Rostrum large, inverted trapezoid; anterior margin slightly convex in ♀, virtually straight in ♂. Cephalothoracic shield broadly bell-shaped; lateral margins fringed with closely set spinules. Pedigerous somites bearing legs 2–4 with strongly developed pleurotergites, those of leg 4-bearing somite backwardly produced and embracing leg 5-bearing somite and anterior half of genital double-somite; each provided with strong spinules along lateral margins. Leg 5-bearing somite reduced, without marked pleurotergites. Genital double-somite completely fused. Second and third abdominal somites with lobate pleurotergites, those of penultimate somite embracing anal somite and anterior half of caudal rami. Anal somite without expanded pleurotergites; operculum naked. Caudal rami flattened, longer than wide, with straight outer and markedly convex inner margin; with medially directed spinules along inner margin and finer spinules along outer margin; with seven setae, all of which located near posterior margin of ramus; setae IV–V with fracture planes and fused at base.
Antennule slender, 5-segmented and with aesthetasc on segment 3 in ♀, subchirocerate, 8-segmented and with aesthetasc on segment 5 in ♂; without spinous processes on segments 1–2; segments 1–3 with setules along anterior margin; segment 3 elongate in ♀. Antenna with allobasis bearing unipinnate seta along abexopodal margin. Exopod 1-segmented, with four elements. Mandible with slender gnathobase; palp small, comprising unisetose basis with incorporated endopod and discrete exopod, armed with three and one seta(e), respectively. Maxillule without defined rami; armature of palp represented by one lateral and three distal setae. Maxilla with two coxal endites; endopod with two setae. Maxilliped elongate and slender; syncoxa with one seta; endopod represented by acutely recurved claw with minute accessory seta at its base.
Legs 1–4 with very wide and narrow intercoxal sclerites. Leg 1 with sparsely plumose inner and outer seta on basis; exopod 3-segmented with long outer spine on exp-1, extending beyond distal margin of exp-3 and bearing stiff spinules along its outer margin; exp-2 with outer unipinnate spine; exp-3 with two unipinnate spines and two geniculate setae; endopod 2-segmented, prehensile, enp-1 unarmed, enp-2 with short claw but accessory seta not discernible. Legs 2–4 with transversally elongate bases, with long (P2–P3) or short (P4) outer seta; with 3-segmented exopods and 2-segmented endopods (except for P3 endopod 3-segmented in ♂); outer exopodal spines typically unipinnate in distal half only, inner setae very long and plumose; outer margin of P2–P4 enp-2 with double row of flimsy setular extensions. Leg 3 ♂ with outwardly recurved, spinous apophysis on enp-2; enp-3 with one inner and two apical setae. Armature formulae:
Exopod | Endopod | |
P2 | 0.1.123 | 0.120 |
P3 | 0.1.223 | 0.121 [0.apo.120 in ♂] |
P4 | 0.1.223 | 0.121 |
Leg 5 biramous; baseoendopod very elongate, backwardly recurved, with outer basal seta arising from short dorsal setophore; endopodal armature represented by three setae in ♀ and one seta in ♂; exopod with four elements in ♀ and three elements in ♂.
Genital field ♀ located near border with leg 5-bearing somite. P6 forming well developed operculum with two small setae in ♀; asymmetrical in ♂ (with dextral or sinistral configuration), with outer distal corner bearing one minute seta.
Type species. Philippiphonte aspidosoma gen. et sp. n. (by original designation).
Etymology. The genus is dedicated to Rudolph Amandus Philippi (14 September 1808–23 July 1904), author of the type genus Laophonte Philippi, 1840 and of the first publication to adopt the term “copepod” in its title (
South Korea, East Sea (Sea of Japan), Gajaebawi, Dokdo island (Liancourt Rocks), 37°14'49.37"N, 131°51'48.24"E, shell gravel, 22 m depth (Figure
Type material. Holotype ♀ dissected on 11 slides (reg. no NIBRIV0000816435), allotype ♂ dissected on 11 slides (reg. no NIBRIV0000816434), remaining paratypes (9 ♀♀, 1 ♂) preserved in formalin (reg. no NIBRIV0000816433). All type specimens were collected on 23 April 2015 from the type locality and are deposited in the National Biological Resources Center (NIBR), Incheon.
1 ♂ from Mulgol, Dokdo island, 37°14'35.16"N, 131°51'51.37"E, 15 m depth, 27 June 2015 (reg. no MInRB-Hr15-L001); 1 ♂ from the old harbour of Dokdo island, 37°14'27.31"N, 131°52'16.69"E, 12 m depth, 27 June 2015 (reg. no MInRB-Hr15-L002); 2 ♀♀, 4 ♂♂, 24 August 2016 from type locality (Figure
Body length from anterior margin of rostrum to posterior margin of caudal rami 536–612 μm (mean = 574 μm; n = 12; holotype = 552 μm); maximum width measured at level of leg 3-bearing somite: 338 μm (in holotype). Body (Figure
Philippiphonte aspidosoma gen. et sp. n. (♀): A urosome and right leg 5, ventral B mandible [inset showing gnathobase from different angle] C maxillule, anterior [inset showing small unipinnate element arising from posterior surface] D maxilla E maxilliped F leg 1, anterior [exp-2 and -3 disarticulated].
Caudal rami (Figure
Antennule (Figure
Antenna (Figure
Mandible (Figure
Maxillule (Figure
Maxilla (Figure
Maxilliped (Figure
Leg 1 (Figure
Legs 2–4 (P2–P4) (Figs
Leg 5 (Figure
Genital field (Figure
Slightly smaller than female; body length from anterior margin of rostrum to posterior margin of caudal rami 461–527 μm (mean = 489 μm; n = 8; allotype = 523 μm); maximum width measured near posterior margin of cephalothorax: 315 μm (in allotype). Body (Figure
Antennule (Figure
Leg 3 (Figure
Leg 5 (Figure
Sixth legs (P6) (Figure
The specific epithet is derived from the Greek άσπίς, meaning shield, and σῶμα, meaning body, and alludes to the dorsoventrally flattened shield-shaped body form.
The new genus can readily be identified as a member of the family Laophontidae because of the morphology of leg 1, including the presence of a pedestal on the basis used for the insertion of the endopod, the displacement of the inner spine onto the anterior surface of the basis, and the modification of the outer (= anterior) distal element of enp-2 into a large non-geniculate claw (
Philippiphonte aspidosoma is morphologically radically divergent from other members of the family, justifying its assignment to a new genus. Unique autapomorphies that define the genus Philippiphonte include (a) the extremely dorsoventrally flattened, porcellidiid-like body shape in both sexes (Figs
The interrelationships of the Laophontidae are poorly resolved despite decades of morphological studies with the least confidently resolved part of the tree being the relative positions of the 65 genera in the subfamily Laophontinae. The significance of patterns of swimming leg sexual dimorphism in unravelling relationships among certain laophontid lineages has been demonstrated repeatedly in a number of studies (e.g.,
All members of the families Porcellidiidae and Peltidiidae are exclusively dorsoventrally depressed. However, flattened body shapes have also evolved in many other harpacticoid lineages (Figure
Harpacticoid copepods exhibiting dorsoventrally flattened body shapes (females only, dorsal view; genital double-somite shaded). A Philippiphonte aspidosoma (Laophontidae) B Porcellidium viride (Philippi, 1840) (Porcellidiidae) C Neopeltopsis pectinipes Hicks, 1976 (Peltidiidae) D Hamondia superba Huys, 1990 (Hamondiidae) E Alteutha oblonga (Goodsir, 1845) (Peltidiidae) F Peltidium purpureum Philippi, 1839 (Peltidiidae) G Zaus abbreviatus Sars, 1904 (Harpacticidae) H Paramenophia platysoma (Thompson & Scott, 1903) (Thalestridae) I Xouthous purpurocinctus (Norman & Scott, 1905) (Pseudotachidiidae) J Xouthous parasimulans (Médioni & Soyer, 1968) (Pseudotachidiidae) K Mucropedia kirstenae Bouck, Thistle & Huys, 1999 (Harpacticidae) L Donsiella phycolimnoriae Hicks, 1990 (Pseudotachidiidae) M Alteuthoides kootare Hicks, 1986 (Peltidiidae) N Peltidiphonte rostrata Gheerardyn & Fiers in Gheerardyn, Fiers, Vincx & De Troch, 2006 (Laophontidae) O Peltobradya bryozoophila Médioni & Soyer, 1968 (Ectinosomatidae) P Scutellidium arthuri Poppe, 1884 (Tisbidae).
The shape of the rostrum, the general ovoid, shield-shaped habitus and the degree of dorsoventral compression in Philippiphonte are somewhat reminiscent of the condition in the Porcellidiidae (compare Figure
The transition from an epibenthic to a mesopsammic life style has evolved independently and successfully many times in various lineages of the Harpacticoida. Adaptation to the three-dimensional labyrinth of the interstitial system of sand grains and shell gravel is primarily achieved by miniaturisation and/or the adoption of vermiformicity or a cylindrical body shape, thus enhancing flexibility and wriggling ability. Dwarfism often leads to a simplification in body morphology, most commonly resulting in the loss of swimming leg segments and rami or even entire limbs. Within the Laophontidae such regressive evolution linked to an interstitial mode of life can be observed in at least 14 genera characterised by a cylindrical body form, including Laophontina Norman & Scott, 1905, Klieonychocamptoides Noodt, 1958, Afrolaophonte Chappuis, 1960, Stygolaophonte Lang, 1965, Mexicolaophonte Cottarelli, 1977, Galapalaophonte Mielke, 1981, Novolaophonte Cottarelli, Saporito & Puccetti, 1983, Indolaophonte Cottarelli, Saporito & Puccetti, 1986, Amerolaophontina Fiers, 1991, Wellsiphontina Fiers, 1991, Spiniferaphonte Gheerardyn & Fiers, 2007, Raowellsia Özdikmen, 2008, Aequinoctiella Cottarelli, Bruno & Berera, 2008, and Fiersiphontina Bruno & Cottarelli, 2011 (
Folioquinpes chathamensis and F. mangalis assume a bizarre geographical distribution, including widely separated records from the Atlantic and Western Pacific oceanic basins. Remarkably, both species have been recorded from the northern coast of Papua New Guinea and exist in relative proximity in the Caribbean. Unless both species are widely distributed throughout the Indo-Pacific (for which there is no compelling evidence at present) this may indicate the existence of a complex of sibling species, each with a more restricted distribution. In this context,
Number of segments in female antennule (A1), number of setae on antennary exopod (A2) and armature of P2–P4 (female) and P5 (both sexes) of members of Onychocamptus Daday, 1903 and allied genera.
A1 | A2 | P2 | P3 | P4 | P5♀ | P5♂ | |||||
---|---|---|---|---|---|---|---|---|---|---|---|
exp | enp | exp | enp | exp | enp | exp | benp | exp | |||
ONYCHOCAMPTUS | |||||||||||
mohammed (Blanchard & Richard, 1891) | 5 | 4 | 0.1.123 | 0.220 | 0.1.123 | 0.321 | 0.1.123 | 0.111 | 3 | 3 | 2 |
bengalensis (Sewell, 1934) | 5 | 4 | 0.1.123 | 0.220 | 0.1.123 | 0.321 | 0.1.123 | 0.111 | 3 | 3 | 2 |
besnardi Jakobi, 1954 | 5 | 4 | 0.1.123 | 0.220 | 0.1.123 | 0.321a | 0.1.022 | 0.111 | 3 | 3 | 2 |
vitiospinulosa (Shen & Tai, 1963) | 5 | 4 | 0.1.123 | 0.220 | 0.1.123 | 0.321 | 0.1.123 | 0.111 | 3 | 2 | 2 |
anomalus (Ranga Reddy, 1984) | 5 | 1 | 0.1.123 | 0.220 | 0.1.123 | 0.321 | 0.1.122 | 0.111 | 4 | 3 | 3 |
taifensis Kikuchi, Dai & Itô, 1993 | 5 | 4 | 0.1.123 | 0.120 | 0.1.123 | 0.321 | 0.1.123 | 0.111 | 3 | 3 | 2 |
krusensterni Schizas & Shirley, 1994 | 5 | 4 | 0.1.123 | 0.220 | 0.1.123 | 0.321 | 0.1.122b | 0.111 | 3 | 3 | 2 |
FOLIOQUINPES | |||||||||||
chathamensis (Sars, 1905) | 5 | 4 | 0.1.123 | 0.220 | 0.1.123 | 0.321 | 0.1.123 | 0.111 | 3 | 3 | 2c |
indicus sp. n. | 5 | 4 | 0.1.123 | 0.220 | 0.1.123 | 0.321 | 0.1.123 | 0.111 | 4 | 3 | ? |
mangalis Fiers & Rutledge, 1990 | 4 | 4 | 0.1.123 | 0.220 | 0.0-1d.123 | 0.221 | 0.0.123 | 0.111 | 4 | 2 | 2 |
pseudomangalis sp. n. | 4 | 4 | 0.1.123 | 0.220 | 0.1.123 | 0.221 | 0.0.123 | 0.111 | 4 | 3 | 2 |
ONYCHOQUINPES | |||||||||||
permixtionis Gómez & Morales-Serna, 2013 | 5 | 4 | 0.1.123 | 0.220 | 0.1.123 | 0.321 | 0.1.123 | 0.111 | 3 | 3 | 2 |
PSAMMOLAOPHONTE e | |||||||||||
spinicauda Wells, 1967 | 5 | 2 | 0.0.022 | 0.020 | 0.0.022 | 0.021 | 0.0.022 | 0.011 | 4 | 3 | 3 |
Diagnosis.Laophontidae. Body moderately to strongly dorsoventrally depressed. Integument of cephalothorax and body somites with dense pattern of long spinules; dorsal posterior margins of somites with sensillate tubercles. Rostrum partially delimited at base; prominent and bell-shaped, with (F. mangalis, F. pseudomangalis sp. n.) or without (F. chathamensis, F. indicus sp. n.) spinules between apical sensilla. Genital double-somite ♀ bilaterally incised, with dorsal and lateral transverse chitinous ribs marking original segmentation. Pleural extensions of ♀ abdominal somites moderately to strongly (conical) developed. Caudal ramus elongate, cylindrical, with spinules along inner and (often) outer margin; with seven setae; seta V well developed, with fracture plane, fused to short seta IV; seta VI reduced, setiform; ramus slightly sexually dimorphic in F. mangalis (inner margin less convex in ♂). Anal operculum spinulose.
Sexual dimorphism in antennule, P5, P6 and in genital segmentation. Slight dimorphism in exopods of P3–P4, abdominal ornamentation and caudal ramus shape.
Antennule short and 4- or 5-segmented in ♀, all segments densely spinulose; 8-segmented and subchirocer with three segments distal to geniculation in ♂; segment 1 with strong spinules along anterior margin; segment 2 sometimes with small blunt process near posterior margin; with aesthetasc on segment 3 (♀) or 5 (♂) and probably as part of acrothek on apical segment; segment 6 ♂ with three hyaline extensions. Antenna with four setae on exopod; allobasis with abexopodal seta. Mandibular palp elongate, 1-segmented; with one basal, one exopodal and three endopodal setae. Maxillule with defined exopod bearing two setae. Maxilla with three endites on syncoxa; endopod represented by two setae. Maxilliped moderately robust; syncoxa with one seta; basis with spinules along both margins; endopodal claw curved, with accessory seta at base.
P1 with 2-segmented exopod, with long pinnate outer spine on exp-1, and three spines and two geniculate setae on exp-2; endopod moderately stout, enp-1 without inner seta, enp-2 with minute seta and short, strong claw. Swimming legs with 3-segmented exopods and 2-segmented endopods in both sexes; segments and/or outer spines of P3–P4 exopods somewhat stronger in ♂. Armature formula as follows:
Exopod | Endopod | |
---|---|---|
P2 | 0.1.123 | 0.220 |
P3 | 0.(0–1)*.123*: variability in F. mangalis | 0.(2–3)21 |
P4 | 0.(0–1).123 | 0.111 |
P5 ♀ large, with separate, densely hirsute rami; exopod elongate-oval, arising from pedestal, with 2–3 setae laterally and one short dilated spine apically; baseoendopod with triangular or rectangular endopodal lobe bearing one apical and 1–3 lateral setae. P5 ♂ incorporated into supporting somite; endopodal lobe completely absent (no armature); exopod typically not defined at base, small, with two setae.
P6 ♀ with two minute setae; P6 ♂ asymmetrical, membranous flaps with two setae.
Copepodids IV–V without modified P4 in ♀ (cf.
Euryhaline but primarily brackish or freshwater, free-living.
Type species. Folioquinpes mangalis Fiers & Rutledge, 1990 (by original designation).
Other species. F. chathamensis (Sars, 1905), F. indicus sp. n., F. pseudomangalis sp. n.
Species inquirenda. Folioquinpes chathamensis (Sars, 1905) sensu
1 | Anterior margin of rostrum with spinules between sensilla; antennule ♀ 4-segmented; P3 enp-2 with two inner setae; P3–P4 exp-2 without inner seta | 2 |
– | Anterior margin of rostrum without spinules between sensilla; antennule ♀ 5-segmented; P3 enp-2 with three inner setae; P3–P4 exp-2 with inner seta | 3 |
2 | Cephalothorax bilaterally incised; P5 ♀ endopodal lobe with two setae | F. mangalis Fiers & Rutledge, 1990 |
– | Cephalothorax not bilaterally incised; P5 ♀ endopodal lobe with three setae | F. pseudomangalis sp. n. |
3. | P4 enp-2 longer than enp-1; P5 exopod ♀ with two outer setae | F. chathamensis (Sars, 1905) |
– | P4 enp-2 shorter than enp-1; P5 exopod ♀ with three outer setae | F. indicus sp. n . |
Laophonte chathamensis Sars, 1905
Folioquinpes
chathamensis
(Sars, 1905)
Onychocamptus
spec. sensu
New Zealand, Chatham Islands, Wharekauri (= Chatham Island), Te Whanga Lagoon; shallow brackish water.
480 μm (♀), slightly smaller (♂) [
Folioquinpes chathamensis resembles F. indicus sp. n. in the absence of spinules along the anterior margin of the rostrum, the 5-segmented condition of the female antennule, the presence of three inner setae on the distal endopodal segment of leg 3, and of the inner seta on the middle exopodal segment of legs 3–4. The alternative states, including the 4-segmented female antennule, are displayed in the other two species of the genus (Table
Hamond (in
Papua New Guinea, Capital District, Motupore Island; mangrove along northern shore; algae on pneumatophores.
600 μm (♀), 400 μm (♂) [
Folioquinpes mangalis differs from its congeners in the bilaterally incised cephalothorax and the more strongly developed P5 ♀ endopodal lobe which bears only two setae. The dense spinular ornamentation on the anterior surface of leg 5 has not been documented in other species of the genus. The species is similar to P. pseudomangalis sp. n. in the strongly depressed body, the distinct pleural extensions on the urosomites, the 4-segmented female antennule, the lack of the inner seta on P4 exp-2 (and P3 exp-2 but see below) and the presence of only two inner setae on P3 enp-2.
Folioquinpes mangalis has been found on pneumatophores of mangrove trees along the southern (type locality) and northern coast (Sepik River delta) of Papua New Guinea and on Spartina alterniflora stems from marshes in Cocodrie, Louisiana (
Laophonte
chathamensis
Sars, 1905 sensu
The original material collected by R.B. Seymour Sewell is no longer available for re-examination. In accordance with
India, Odisha State, Chilika (Chilka) Lake; anchorage at Barkul due east; tow-nettings of brackish water plankton.
400 μm (♀) [
Females of F. indicus differ from those of F. chathamensis primarily in the morphology of the P5 exopod which is more oval, has three outer setae (instead of two) and a very short, blunt spine apically (Sewell may have missed the flagellate tip). Additional differences include the more slender P1 endopod (enp-1:enp-2 ratio 5.3 vs 4.6) and the shorter P4 enp-2 (enp-1:enp-2 ratio 1.1 vs 0.8).
The authenticity of other records from the Indian peninsula is unclear since none was accompanied by illustrations.
Folioquinpes
mangalis
Fiers & Rutledge, 1990 sensu
Korea, Jeju Island, Aewol; washings of invertebrates and intertidal stones.
In accordance with
600 μm (♀), 400 μm (♂) [to be confirmed – see below].
Laophonte
chathamensis
Sars, 1905 sensu
South Africa, Western Cape Province, Cape Town, Muizenberg, Sandvlei; freshwater lake.
470–670 μm (♀) [
We thank Messrs. Hyun Soo Rho (KIOST) and Jae Ho Lee for their helpful support in collecting samples. This study was partially supported by the project “The Discovery of Korean Indigenous Species” of the National Institute of Biological Resources (NIBR), Republic of Korea to R. Huys, and by the Marine Biotechnology Program of the Korea Institute of Marine Science and Technology Promotion (KIMST) funded by the Ministry of Oceans and Fisheries (MOF) (number 20170431) to J. Lee. This work was also conducted with the support offered through the research programme of KIOST (Contract No. PE99662) to J. Lee.