Research Article |
Corresponding author: Kristine N. White ( kristine.white@gcsu.edu ) Academic editor: Rachael Peart
© 2024 Kristine N. White, Sally J. Sir.
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:
White KN, Sir SJ (2024) Caribbean Amphipoda (Crustacea) of Panama. Part II: parvorder Hadziidira. ZooKeys 1195: 249-296. https://doi.org/10.3897/zookeys.1195.116721
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Amphipods in the parvorder Hadziidira are typically associated with algae, sponges, or coral rubble. Members of the parvorder have a gnathopod 2 that is stouter than gnathopod 1, a pair of dorsal robust setae on urosomite 2, and a basofacial robust seta on the uropod 1 peduncle. Within the parvorder, six families are documented from Bocas del Toro, Panama, represented by 26 species. This research documents range extensions for all 26 species and an identification key to the species of Caribbean Hadziidira of Panama is provided.
Los anfípodos del parvorden Hadziidira suelen estar asociados con algas, esponjas o escombros de coral. Los miembros del parvorden tienen un gnatópodo 2 que es más robusto que el gnatópodo 1, un par de setas dorsales robustas en el urosomita 2 y una seta basofacial robusta en el pedúnculo del urópodo 1. Dentro del parvorden se documentan seis familias de Bocas del Toro, Panamá, representadas por 26 especies. Esta investigación documenta extensiones de rango para las 26 especies y se proporciona una clave de identificación para las especies de Hadziidira caribeña de Panamá.
Bocas del Toro, Hadziidae, Hornellidae, identification key, Maeridae, Megaluropidae, Melitidae, Pontogeneiidae
Parvorder Hadziidira S. Karaman, 1943 is comprised of 1159 species around the world (
Within the parvorder Hadziidira, 26 species of amphipods were collected from Bocas del Toro, Panama, with representatives from families Hadziidae, Hornellidae, Maeridae, Megaluropidae, Melitidae, and Pontogeneiidae. All species are diagnosed herein. An identification key is provided to distinguish between the Hadziidira species known from the Caribbean waters of Panama.
Various substrates were collected by hand and placed into buckets or plastic bags from various sites around Bocas del Toro, Panama at depths of 0.2–12 m. Coral rubble was elutriated with freshwater to remove amphipods and other samples were sorted through by hand. Live amphipods were sorted to morphospecies, placed in clove oil for imaging, and preserved in 99.5% EtOH for later examination. Preserved specimens were transferred to glycerol, measured from the tip of the rostrum to the base of the telson, and dissected under a stereomicroscope. Specimens were illustrated using a Meiji MT5900L phase contrast microscope with an Olympus U-DA drawing tube attached or an Olympus BH2 differential interference contrast microscope with an Olympus BH2-DA drawing tube attached. Illustrations were digitally inked following
Parvorder Hadziidira S. Karaman, 1943
Antenna 1 accessory flagellum 2-articulate; lower lip lacking inner lobes; gnathopod 1 smaller than gnathopod 2; coxa 4 not excavate posteriorly; pleonites 1–3 smooth; uropod 3 inner ramus minute, outer ramus greatly elongated, 2-articulate, article 2 short; telson deeply cleft.
Eriopisa schoenerae Fox, 1973: 153–159, figs 5–8.
Protohadzia schoenerae:
Panama • 2.8–5 mm • 1 ♀; Bocas del Toro, Hospital Bight; 9.304483°N, 82.131617°W; depth 1.5 m, surface of dead coral; 7 Aug 2005; S.E. LeCroy leg.;
Male gnathopod 2 propodus palm with acute apical protrusion, much larger than female gnathopod 2; epimeron 3 with simple small posteroventral tooth; telson apically acute with apical spines.
USA: Florida from Biscayne Bay to the Dry Tortugas (
These amphipods are associated with coral rubble, algae, and seagrass near coral reefs at depths of 1–5 m. Panamanian specimens agree closely with previous descriptions of the species and are easily distinguishable based on the uropod 3, gnathopod 2, and epimeron 3, even in smaller specimens.
Eyes oval. Maxilla 2 inner plate with dense facial setae. Coxa 1 produced anteroventrally. Pereopod 7 basis weakly expanded, posterior margin serrate. Urosomite segments usually serrate. Uropod 3 rami foliaceous, apically truncate, extending beyond tips of uropods 1 and 2. Telson deeply cleft.
Ceradocus sheardi
Shoemaker, 1948: 7–9, fig. 2;
Panama • 5–10 mm • 1 ♀; Bocas del Toro, Swan Cay; 9.4536°N, 82.300033°W; depth 2 m, coral rubble; 24 June 2023; K.N. White leg.;
Antenna 1 accessory flagellum 7- or 8-articulate. Gnathopod 2 not sexually dimorphic, right and left sides similar; propodus enlarged, palm convex, defined by notch. Pereopod 7 basis without posterodistal lobe. Pleosome and urosome dorsally serrate. Epimera 1–3 posterior margins serrate. Telson approximately as long as wide with strong apical spines.
USA: South Florida from Biscayne Bay to the Dry Tortugas (
These amphipods are common among coral rubble and under rocks at depths of 1–52 m. Panamanian specimens agree closely with previous descriptions of the species and are easily distinguishable based on the uropod 3, gnathopod 2, and heavily serrate epimeron and urosome.
Ceradocus shoemakeri
Fox, 1973: 147–152, figs 1–4;
Panama • 2.2–7 mm • 1 ♀; Bocas del Toro, Hospital Point; 9.3336°N, 82.218833°W; depth 15- m, coral rubble and Halimeda; 6 Aug 2005; S. DeGrave leg.;
Antenna 1 accessory flagellum 4- or 5-articulate. Gnathopod 2 sexually dimorphic, right and left sides dissimilar; enlarged side palm oblique with two subquadrate and one triangular projection. Pereopod 7 basis with small posterodistal lobe. Pleosome and urosome dorsally smooth. Epimera 1–3 posterior margins serrate. Telson approximately as long as wide with subapical setae.
U.S.A.: South Florida from Biscayne Bay to the Dry Tortugas; Apalachee Bay, Perdido Key, Florida (
These amphipods are associated with coral rubble, algae, and sponges at depths of 0.5–15 m. Panamanian specimens have a dorsally smooth pleosome and urosome;
Antenna 1 elongate, at least 1/3 of body length; accessory flagellum 2- or 3- articulate. Mandibular palp article 3 falcate, anterior margin with pectinate setae. Uropod 1 peduncle with basofacial spine; uropod 3 rami subequal in length.
Elasmopus balkomanus
Thomas & Barnard, 1988: 838–842, figs 1–3;
Panama • 1.6–8 mm • 1 ♀; Bocas del Toro, Crawl Cay; 9.2475°N, 82.1290°W; depth 5 m, among coral rubble; 12 Aug 2021; K.N. White leg.;
Gnathopod 1 male propodus subovate, palm oblique, female propodus slender, ventral margin straight. Gnathopod 2 male propodus palm densely setose with crenulate longitudinal ridge on medial surface, female propodus with 2 spines at palmar angle. Pereopod 5 basis posterior margin concave. Pereopod 7 basis posterior margin without long setae, articles 4 and 5 of male unexpanded, slender. Epimeron 3 posteroventral margin with small tooth. Telson inner lobes shorter than outer lobes, apically acute.
U.S.A.: South Florida, Looe Key (
These amphipods are associated with algal turf and coral rubble at depths of 1–5 m. Panamanian specimens have a less setose gnathopod 2 propodus and less concave pereopod 5 basis than described by
Elasmopus elieri Ortiz, Lalana & Varela, 2004: 36–39, figs 1, 2.
Panama • 3.5–6 mm • 9 ♂, 9 ♀; Bocas del Toro, Lime Point; 9.4149°N, 82.33225°W; depth 0.2–0.5 m, among red algae and coral rubble; 5 Aug 2005; S. DeGrave leg.;
Gnathopod 1 propodus subrectangular, palm oblique. Gnathopod 2 male propodus elongate, palm concave, with large distal triangular tooth, medial surface with two subtriangular processes; female propodus elongate, narrow, palm oblique with two spines at palmar angle. Pereopod 5 basis posterior margin evenly convex. Pereopod 7 basis posterior margin without long setae. Epimeron 3 posteroventral margin with small tooth. Telson inner lobes subequal in length with outer lobes, apically rounded.
Cuba: Cayo Diego Pérez (
These amphipods are associated with algae, and coral rubble at depths of 0–3 m. Panamanian specimens closely resemble specimens described by
Maera levis Smith, 1873: 559.
Elasmopus laevis:
Panama • 5–10 mm • 1 ♂; Bocas del Toro, Playa Bluff; 9.3905°N, 82.23725°W; depth 0 m, among algae; 5 Aug 2005; T.A. Haney leg.;
Gnathopod 1 propodus subrectangular, palm transverse. Gnathopod 2 male propodus with deep medial depression, lined with groups of long setae along ventral margin, with one small medial tooth, female propodus with two spines at palmar angle slightly longer than spines on palmar margin. Pereopod 5 basis posterior margin evenly convex. Pereopod 7 basis posterior margin without long setae, articles 4 and 5 of male expanded, articles 5 and 6 with long posterior setae. Epimeron 3 posteroventral margin with small tooth, sometimes with serrated edge. Telson inner lobes longer than outer lobes, apically subacute.
U.S.A.: Cape Cod, Massachusetts (
These amphipods are associated with seagrass, algae, and coral rubble at depths of 0–11 m. Panamanian specimens show variation in the level of acuteness of the telson apices and the posterior margin of epimeron 3. Gulf of Mexico and western Atlantic specimens are described as having acute telson lobes (subacute in Panamanian specimens) and all Panamanian specimens show the posteroventral tooth on epimeron 3, whereas this species is sometimes described as having an entire epimeron 3.
Elasmopus rapax
(non Elasmopus rapax Costa, 1851):
Elasmopus aff. rapax:
Elasmopus longipropodus Senna & Souza-Filho, 2011: 59–66, figs 1–6.
Panama • 2.5–7 mm • 3 ♂, 3 ♀; Bocas del Toro, Swan Cay; 9.453333°N, 82.298333°W; depth 2–3 m, among algae; 4 Aug 2005; S. DeGrave leg.;
Gnathopod 1 propodus subovate, palm oblique. Gnathopod 2 propodus elongate, male palm shorter than posterior margin with two large, rounded processes and one large subacute process at palmar angle. Pereopod 7 basis posterior margin with long setae, articles 4 and 5 of male unexpanded. Epimeron 3 posterior margin serrate. Uropod 3 rami subequal or slightly unequal in length. Telson inner lobes longer than outer lobes, apically rounded.
Brazil: from Rio Grande do Norte State to Rio de Janeiro State (Senna and Souza-Filho, 2011); Panama: Bocas del Toro (present study).
These amphipods are associated with algae, sponges, and coral rubble at depths of 1.5–15 m. Panamanian specimens agree closely with the description provided by
Maera pocillimanus Bate, 1862: 191, pl. 34, fig. 7.
Elasmopus pocillimanus:
Panama • 4–8 mm • 1 ♀; Bocas del Toro, Isla Solarte; 9.2475°N, 82.1290°W; depth 1–4 m, among coral rubble; 8 Aug 2021; K.N. White leg.;
Gnathopod 1 propodus subrectangular, palm transverse. Gnathopod 2 male propodus with deep medial depression, lined with groups of long setae along ventral margin, with one small medial tooth, female propodus with two spines at palmar angle slightly longer than spines on palmar margin. Pereopod 5, basis posterior margin evenly convex. Pereopod 7 basis posteroventral margin with long setae, articles 4 and 5 of male expanded, articles 5 and 6 with long posterior setae. Epimeron 3 posteroventral margin entire, sometimes with small tooth or weakly crenulate. Telson inner lobes longer than outer lobes, apically rounded.
Cosmopolitan distribution in warm temperate and tropical waters (
These amphipods are associated with algae and coral rubble at depths of 0–30 m. Panamanian specimens show variation in the amount of crenulation of epimeron 3 posterior margin, but consistently have rounded apices on the telson. Other characters align well with previous descriptions of E. pocillimanus. See
Elasmopus thomasi Ortiz & Lalana, 1994: 297–301, figs 4–6.
Panama • 2–5 mm • 2 ♀, 4 juvenile.; Bocas del Toro, Swan Cay; 9.453333°N, 82.298333°W; depth 3 m, among algae; 4 Aug 2005; T.A. Haney leg.;
Gnathopod 1 propodus subovate, palm oblique. Gnathopod 2 propodus subovate, male palm with three processes and two notches; dactylus resting in notch at palmar angle. Pereopod 5 basis posterior margin evenly convex. Pereopod 7 basis posterior margin without long setae, articles 4 and 5 of male unexpanded. Epimeron 3 posterior margin serrate. Uropod 3 inner ramus shorter than outer ramus. Telson inner lobes longer than outer lobes, apically rounded.
Cuba: North coast (
These amphipods are associated with algae and coral rubble at depths of 0–3 m. Panamanian specimens closely resemble specimens described from Cuba and can be readily distinguished by the shape of gnathopod 2 propodus and the rounded apices of the telson.
Antenna 1 accessory flagellum 4-articulate. Mandibular palp article 2 longer than articles 1 or 3, article 3 slender, linear. Lower lip inner lobes present. Maxilla 1 and 2 inner plates lacking or with scarce medial setae. Gnathopods 1 and 2 small, subchelate. Epimeral plates smooth. Uropod 3 rami subequal in length, outer ramus minutely bi-articulate. Telson cleft, lobes apically excavated.
Meximaera diffidentia
Barnard, 1969b: 209–210, figs 21–22;
Maera caroliniana:
Panama • 4–6 mm • 1 ♂; Bocas del Toro, STRI Point; among coral rubble; 7 Aug 2005; S. DeGrave leg.;
Eyes oval. Gnathopod 1 carpus subequal to propodus. Gnathopod 2 propodus palm oblique without U-shaped excavation. Pereopods with simple dactyls; pereopod 7 basis slimmer than long, without posterodistal lobe. Uropod 3 rami three times length of peduncle, distally truncated, outer ramus with minute second article. Telson cleft, with one long and one short apical spine.
U.S.A.: North Carolina (
These amphipods are associated with sand and coral rubble at depths of 0–12 m. Panamanian specimens agree closely with the description provided by
Mandibular palp article 1 not lengthened or tooth-like; article 3 narrow. Gnathopod 1 carpus with dorso-distal excavation. Gnathopod 2 propodus palmar corner at a right angle; dactylus outer margin bare or with one seta. Pereopod dactyli bifid; pereopod 7 basis with posterodistal lobe.
Maera ceres Ruffo, Krapp & Gable, 2000: 11–13, figs 4–6.
Panama • 2–3 mm • 3 ♂, 5 ♀; Bocas del Toro, Drago; 9.418056 N, 82.3375°W; depth 3 m, among coral rubble; 9 Aug 2021; K.N. White leg.;
Antenna 1 accessory flagellum 7-articulate. Gnathopod 1 coxa anteroventrally rounded; carpus with dorsal depression and two short and four long facial setal rows. Gnathopod 2 propodus palmar margin with shallow U-shaped excavation between two subquadrate projections, palm defined by large projection; dactylus medially expanded, smooth. Telson inner corner acutely produced, each lobe with one medium and three long apical spines.
Bermuda: St. George’s Parish (
These amphipods are associated with algae and coral rubble at depths of 0–3 m. Panamanian specimens closely resemble previously described specimens and can readily identified based on the gnathopod 2 propodus palm ornamentation.
Quadrimaera cristianae Krapp-Schickel & Ruffo, 2000: 199–203, figs 3, 4.
Panama • 2–3.5 mm • 1 ♀; Bocas del Toro, Playa Bluff; 9.3905°N, 82.23725°W; depth 0 m, among algae; 5 Aug 2005; T.A. Haney leg.;
Antenna 1 accessory flagellum 6-articulate. Gnathopod 1 coxa anteroventrally rounded; carpus with slight dorsal depression and two short and four long facial setal rows. Gnathopod 2 propodus palmar margin with three U-shaped excavations increasing in size distally, two subtriangular projections, and one subrectangular projection, palm defined by large projection; dactylus medially expanded. Telson lobes inner corner acutely produced, each with four apical spines and one medio-distal plumose seta.
Turks and Caicos, Fort George Cay; Netherlands Antilles: Curaçao; Lesser Antilles: Bonaire and St. Martin; Venezuela: Margarita Island; Cayman Islands: Grand Cayman Island; Mexico: Yucatán; Brazil: Ceará State; Pernambuco State, Bahia State; Rio Grande do Norte State (
These amphipods are associated with algae and coral rubble at depths of 0–15 m. Panamanian specimens closely resemble previously described specimens, with the main difference being fewer plumose setae on the telson. This species can be readily identified by the gnathopod 2 propodus palm ornamentation.
Maera miranda
Ruffo, Krapp & Gable, 2000: 15–19, figs 7, 8;
Quadrimaera miranda:
Maera quadrimana
(non
Panama • 4–7 mm • 1 ♂, 3 ♀; Bocas del Toro, Swan Cay; 9.453333°N, 82.298333°W; depth 2–3 m; among coral rubble; 4 Aug 2005; S. DeGrave leg.;
Antenna 1 accessory flagellum 6-articulate. Gnathopod 1 coxa anteroventrally rounded; carpus with minute dorsal depression and two short and three long facial setal rows. Gnathopod 2 propodus palmar margin with subrectangular projection followed by a small U-shaped excavation and one short, truncate process, palm defined by small projection; dactylus medially expanded with median point. Telson lobes apically truncate, each with five long apical spines.
Bermuda: St. George’s Parish, Sandy’s Parish (
These amphipods are associated with algae, sponges, ascidians, and coral rubble at depths of 0–15 m. Panamanian specimens closely resemble previously described specimens of this species and can be readily distinguished from other species based on the gnathopod 2 palm ornamentation and broadened dactylus.
Gammarus quadrimanus Dana, 1852: 955–956, pl. 65, fig. 9.
Maera quadrimana:
Panama • 2–3.5 mm • 7 ♂, 2 ♀, 10 juvenile; Bocas del Toro, Drago; 9.418056°N, 82.3375°W; depth 2–4 m, among coral rubble; 9 Aug 2021; K.N. White leg.;
Antenna 1 accessory flagellum 6-articulate. Gnathopod 1 coxa anteroventrally rounded; carpus with distinct dorsal depression and two short and three long facial setal rows. Gnathopod 2 propodus palmar margin with three U-shaped excavations, increasing in size distally, two small subtriangular projections, and one large truncate projection, palm defined by large projection; dactylus smooth, not expanded. Telson lobes apically truncate, inner margins acute, each with four or five medium-to-long apical spines.
Fiji Islands (
Barrier Reef, Australia (
These amphipods are associated with algae and coral rubble at depths of 0–10 m. Panamanian specimens closely resemble the description of specimens from Bermuda, with the gnathopod 2 propodus palmar margin showing a slightly more truncate projection than illustrated by
Quadrimaera sarae Krapp-Schickel & Ruffo, 2000: 206–213, figs 8–10.
Panama • 4–5 mm • 2 ♂, 2 ♀; Bocas del Toro, Swan Cay; 9.453333°N, 82.298333°W; depth 2–3 m; among coral rubble; 4 Aug 2005; S. DeGrave leg.;
Antenna 1 accessory flagellum 7-articulate. Gnathopod 1 coxa anteroventrally produced; carpus elongate with slight dorsal depression and two short and three long facial setal rows. Gnathopod 2 propodus palmar margin with U-shaped excavation surrounded by one subquadrate and one quadrate projection, palm defined by small projection; dactylus medially expanded. Pereopods 3 and 4 dactyli simple; pereopods 5–7 dactyli bifid. Telson, lobes apically excavated, each with four long apical spines.
Turks and Caicos, Fort George Cay; Mexico: Yucatán; Venezuela: Tobago Island (
These amphipods are associated with coral rubble at depths of 0.3–3 m. Panamanian specimens closely resemble previously described specimens, including the characteristic gnathopod 2 propodus palm, simple pereopods 3 and 4 dactyli, and bifid pereopods 5–7 dactyli, which are unique to this species. The excavation on the gnathopod 2 propodus is larger in our 4.2 mm male than shown in the holotype (4.7 mm male) and there are more than three spines on the pereopods 3 and 4 bases in Panamanian specimens, but given the striking similarity in every other character, we are considering this as a regional variation.
Quadrimaera yemanjae Alves, Neves & Johnson, 2018: 569–575, figs 2–7.
Panama • 2–4.5 mm • 10 ♂, 4 ♀; Bocas del Toro, Swan Cay; 9.453333°N, 82.298333°W; depth 2–3 m, among coral rubble; 4 Aug 2005; S. DeGrave leg.;
Antenna 1 accessory flagellum 6-articulate, distal article minute. Gnathopod 1 coxa anteroventrally rounded; carpus with deep dorsal depression and two short and three long facial setal rows. Gnathopod 2 propodus palmar margin with two small U-shaped excavations separated by a subacute process, followed distally by a large truncate process and one large U-shaped excavation, palm defined by large projection; dactylus medially smooth, slightly expanded. Telson lobes apically truncate, inner margins acute, each with four long apical spines.
Brazil: Rio Grande do Norte State (
These amphipods are associated with Halimeda and coral rubble at depths of 0–4 m. Panamanian specimens closely resemble specimens described from Brazil (4.5 mm), with slightly less acute projections on the palm of gnathopod 2 propodus. This can most likely be attributed to the smaller size of the Panamanian specimens (3.8 mm).
Male gnathopod 2 large, asymmetrical, propodus with distolateral crown of spines; female gnathopod 2 equal in size. Pereopods 5–7 dactyli each with accessory spine. Pleosome and urosome with dorsolateral spines. Uropod 3 inner ramus minute; outer ramus 2-articulate. Telson, deeply cleft, tapering to an acute point.
Melita anisochir Krøyer, 1845: 317, pl. II, fig. 1a–p;
Dulichiella anisochir:
Panama • 4–6 mm • 4 ♂, 2 ♀, 4.0 mm; Bocas del Toro, Crawl Cay; 9.2475°N, 82.1290°W; depth 5 m, among coral rubble; 12 Aug 2021; K.N. White leg.;
Gnathopod 1 coxa anteroventral corner produced, rounded, anterior margin concave. Gnathopod 2 propodus distolateral crown with three rounded spines; dactylus apically blunt, overlapping corner of propodus. Pereopods 6 and 7 carpus and propodus without bunches of long slender setae. Epimeron 1 posteroventral corner acute; epimeron 3 posterodistal margin serrate.
Brazil: Rio de Janeiro to Lagoa dos Patos (
These amphipods are associated with soft bottoms and coral rubble at depths of 0–30 m. Panamanian specimens closely resemble previously described specimens, with the exception of a less serrate distal margin on epimeron 3. This difference can most likely be attributed to the size difference of our specimens (4.4 mm) and the lectotype (10.7 mm) described by
Melita fresnelli
Dulichiella
sp. A:
Dulichiella lecroyae Lowry & Springthorpe, 2007: 34–38, figs 25–28.
Panama • 5–10 mm • 1 ♂, 1 ♀; Bocas del Toro, Swan Cay; 9.453333°N, 82.298333°W; depth 2–3 m, in orange sponge; 4 Aug 2005; S. DeGrave leg.;
Gnathopod 1 coxa anteroventral corner not produced, anterior margin straight. Gnathopod 2 propodus distolateral crown with four rounded or subacute spines; dactylus apically hooked, fitting into posterodistal corner of propodus. Pereopods 6 and 7 carpus and propodus without bunches of long slender setae. Epimeron 1 posteroventral corner subquadrate; epimeron 3 posterodistal margin smooth.
U.S.A.: Gulf of Mexico, South Florida, Cedar Keys, Dry Tortugas, South Carolina, Georgia (
These amphipods are associated with sponges and coral rubble at depths of 0–12 m. Panamanian specimens closely resemble previously described specimens, with slight variation in the anteroventral margin of the head. Panamanian specimens show a minutely bifid notch rather than a single acute point.
Male gnathopod 2 large, symmetrical; female gnathopod 2 smaller than in male. Pereopods 5–7, dactyli without accessory spines. Pleosome without serrations. Uropod 3 inner ramus minute; outer ramus 1-articulate. Telson deeply cleft, sides straight or convex, tapering to a point, with apical spines.
Melita planaterga Kunkel, 1910: 34–37, fig. 12;
Panama • 4–9 mm • 7 ♂, 5 ♀; Bocas del Toro, Swan Cay; 9.453333°N, 82.298333°W; depth 2–3 m, among algae; 4 Aug 2005; S. DeGrave leg.;
Male antennae without bottle-brush setae. Male gnathopod 2 propodus ovate, palm densely setose, setae shorter than propodus length; female gnathopod 2 smaller and less setose than in male. Female coxa 6 with lateral ridge at base of hook, anteroventral angle flattened or notched. Urosome segment 1 posterodorsal margin with single median process; urosome segment 2 posterior margin smooth, each side with single dorsolateral spine. Telson lobes apically subacute with long terminal spines.
U.S.A.: Gulf of Mexico, Florida Keys (
These amphipods are associated with algae and coral rubble at depths of 0–3 m. Panamanian specimens closely resemble previously described specimens. Females can be identified easily by the structure of coxa 6 and males have a heavily setose gnathopod 2 propodus. The dark pigmentation is also characteristic of this species. Panamanian specimens ranged from having dark pigment bands as described by
Head, without rostrum. Antenna 1 accessory flagellum present. Gnathopods 1 and 2 subequal and similar. Pereopods 5–7 long and slender. Pleosome and urosome with postero-dorsal teeth. Uropod 3 biramous, rami subequal in length. Telson long and deeply cleft.
Hornellia (Metaceradocus) tequestae
Thomas & J.L. Barnard, 1986a: 478–483, figs 1–3;
Panama • 2–3 mm 1 ♂; Bocas del Toro, Crawl Cay; 9.237675°N, 82.143833°W; depth 2–3 m, among Halimeda; 11 Aug 2021; K.N. White leg.;
Antenna 1 accessory flagellum 4-articulate. Gnathopod 1 carpus posterior margin densely setose. Gnathopod 2 not sexually dimorphic, propodus elongate, palm oblique, smooth. Pereopods 5–7 bases posterior margins strongly serrate; pereopod 7 basis without posterodistal lobe. Epimera 1–3 posterior margins smooth, each with well-developed posteroventral tooth. Telson 1.4 × longer than broad, nearly cleft to base, lobes apically acute with two setae.
U.S.A.: Southeastern Gulf of Mexico (
These amphipods are associated with algae and coral rubble at depths of 0–45 m. Panamanian specimens closely resemble previously described specimens and are readily identified by the distinctly serrate posterodorsal margins of the pleosome and urosome, large posteroventral tooth on each epimeron, and the shape of the telson.
Head rostrum short; ocular lobe with acute cusp. Antenna 1 accessory flagellum 2-articulate. Gnathopod 2 merus with large distal lobe. Uropod 1 peduncle with interramal tooth. Telson with long spines.
Gibberosus devaneyi Thomas & J.L. Barnard, 1986b: 469–475, figs 11, 13–15.
Panama • 2–3 mm • 6 ♂, 56 ♀; Bocas del Toro, Cayo Solarte;; 9.3336°N, 82.218883°W; depth 0.1–1 m, in sand; 7 Aug 2005; S.E. LeCroy leg.;
Head ocular lobe with subacute cusp. Pleosome segment 3 and urosome segment 2 with dorsal serrations, other segments smooth, lacking dorsal spines. Epimeron 3 smooth. Uropod 3 rami continually lined with spines. Telson lobes with several dorsal and two apical spines.
U.S.A.: La Jolla, California; Peru: Chincha Island (
These amphipods are found in sand at depths of 0–18 m. Panamanian specimens closely resemble specimens described from the eastern Pacific with slight variation in the following characters: subacute anterior head margin (acute in Pacific material) and slightly more serrate posterodorsal margin on pleon segment 3. All other characters match well, specifically the smooth posterior margin of epimeron 3 and the continually spinose margins of uropod 3 rami.
Megaluropus longimerus:
Megaluropus
sp.:
Megaluropus myersi McKinney, 1980: 93–98, figs 5–7.
Gibberosus myersi:
Gibberosus
sp. A:
Gibberosus cf. myersi:
Panama • 2–5 mm • 2 ♀; Bocas del Toro, Crawl Cay; 9.237675°N, 82.143833°W; depth 2–3 m, in sand; 11 Aug 2021; K.N. White leg.;
Head ocular lobe with acute cusp. Pleosome segment 3 and urosome segments 1 and 2, with dorsal serrations; urosome segment 2, with one or two dorsal spines. Epimeron 3 serrate. Uropod 3 peduncle with facial spines; rami with sparse marginal spines. Telson each lobe with one dorsal and two apical spines.
U.S.A.: South Carolina to the Florida Keys; southwestern Gulf of Mexico, Tampa Bay, Perdido Key, British Columbia to La Jolla, California (
These amphipods are found in sand at depths of 0–29 m. Panamanian specimens closely resemble previously described specimens. See
Head rostrum long; ocular lobe rounded. Antenna 1 accessory flagellum 1-articulate. Gnathopod 2 merus without distal lobe. Uropod 1 peduncle without interramal tooth. Telson with small spines (if present).
Resupinus spinicaudatus Thomas & J.L. Barnard, 1986b: 445–454, figs 1–5.
Panama • 2–2.5 mm • 2 ♂, 6 ♀; Bocas del Toro, Drago; 9.413433°N, 82.33335°W; depth 0–1 m, in sand; 23 June 2023; K.N. White leg.;
Head eye not filling entire ocular lobe. Pleosome segments 2 and 3 with dorsal serrations. Urosome segments dorsally smooth. Epimera 1–3 with sparse facial setae; epimeron 3 posterior margin with sparse, shallow serrations. Telson covered with dorsal prickle spines.
Belize: Sitee Point (
These amphipods are found in sand at depths of 0.75–1.2 m. Panamanian specimens closely resemble previously described specimens and can be easily identified based on having smooth pleonites 4 and 5, sparsely serrate epimeron 3, and dorsally spinose telson.
Antenna 1 accessory flagellum 1-articulate. Rostrum short. Gnathopods 1 and 2 propodus palmar margins lined with stout peg-like spines. Epimeron 3 posterior margin serrate. Uropod 2 rami subequal with length of uropods 1 and 3.
Eusiroides yucatanensis
McKinney, 1980: 89–93, figs 3, 4;
Panama • 5–7 mm • 1 ♂, 1 ♀, 2 juvenile; Bocas del Toro, Crawl Cay; 9.2376°N, 82.1438°W; depth 1.5–3 m, among coral rubble, 11 Aug 2021; K.N. White leg.;
Pereopods 5–7 basis crenulate; propodus with spine formula 2, 2, 2, 2, and two locking spines. Epimera 1 and 2 smooth, posteroventral corner with acute point; epimeron 3 posterior margin with three serrations. Uropod 3 peduncle 1/2 as long as rami. Telson subtriangular, longer than wide, apices of lobes subacute.
Mexico: Yucatan (
These amphipods are associated with algae and coral rubble at depths of 0–3 m. Panamanian specimens closely resemble previously described specimens and can be easily identified based on the smooth epimera 1 and 2, epimeron 3 having three distinct serrations, and the length of uropod 3 peduncle.
Antenna 1 without accessory flagellum. Rostrum reaching ~ 1/2 length of first article of antenna 1 peduncle. Gnathopods 1 and 2 propodus relatively small, palmar margin lined with slender spines. Epimeron 3 posterior margin serrate. Telson subrectangular, slightly longer than wide, apices of lobes rounded or subtruncate.
Nasageneia bacescui
Ortiz & Lalana, 1994: 285–291, figs 1–5;
Panama • 2.5–5 mm • 1 ♂ Bocas del Toro, Drago; 9.413433°N, 82.33335°W; depth 1–3 m, among red algae; 23 June 2023; K.N. White leg.;
Rostrum narrow, curved, distally acute. Gnathopods 1 and 2 propodus palm each with four spines and several setae. Epimeron 3 posterior margin regularly serrate. Uropod 3 inner ramus slightly shorter than outer ramus Telson cleft ½ of length, lobes not narrowing distally, apically rounded.
U.S.A.: Tampa Bay to the Florida Keys (
These amphipods are associated with algae and coral rubble at depths of 0–4 m. Panamanian specimens closely resemble previously described specimens. This species can be distinguished from the closely related Tethygeneia longleyi based on the narrow, distally acute rostrum, regularly serrate epimeron 3, and wide telson lobes. See
Rostrum reaching ~ 3/4 length of first article of antenna 1 peduncle, linguiform. Gnathopods 1 and 2 propodus relatively small, palmar margin lined with slender spines. Epimeron 3 posterior margin smooth or weakly serrate. Telson subrectangular, slightly longer than wide, apices of lobes rounded or subtruncate.
Pontogeneia longleyi Shoemaker, 1933: 253–254, figs 6, 7.
Tethygeneia longleyi:
Panama • 3–5 mm • 1 ♀; Bocas del Toro, Mangrove Inn; depth 1 m, among Caulerpa; 3 Aug 2005; M. Faust leg.;
Rostrum wide, curved, distally rounded. Gnathopods 1 and 2 propodus palm each with one to three spines and several setae. Epimeron 3 posterior margin smooth or slightly serrate. Uropod 3 inner ramus subequal in length to outer ramus Telson cleft 3/4 of length, lobes narrowing distally, apically rounded.
U.S.A.: Hutchinson Island to the Dry Tortugas, Florida (
These amphipods are associated with algae and sand at depths of 0–11 m. Panamanian specimens closely resemble previously described specimens in all aspects, and have the rounded telson apices as described by
1 | Gnathopod 2 simple; pereopod 7 elongate, distal articles extremely slender; uropod 3 rami broadly paddle-shaped (Fig. |
2 |
– | Gnathopod 2 subchelate; pereopod 7 not elongate, or if elongate, distal articles not unusually slender; uropod 3 rami not broadly paddle-shaped (Fig. |
4 |
2 | Head rostrum short, ocular lobe with cusp; antenna 1 accessory flagellum 2-articulate; gnathopod 2 merus with large distal lobe; uropod 1 peduncle with interramal tooth (Fig. |
3 |
– | Head rostrum long, ocular lobe rounded; antenna 1 accessory flagellum 1-articulate; gnathopod 2 merus without distal lobe; uropod 1 peduncle without interramal tooth (Fig. |
Resupinus spinicaudatus |
3 | Head ocular lobe with subacute cusp; only pleosome segment 3 and urosome segment 2 with dorsal serrations; epimeron 3 smooth; uropod 3 rami continually lined with spines (Fig. |
Gibberosus devaneyi |
– | Head ocular lobe with acute cusp; pleosome segment 3 and urosome segments 1 and 2 with dorsal serrations; epimeron 3 serrate; uropod 3 rami with sparse marginal spines (Fig. |
Gibberosus myersi |
4 | Gnathopod 2 similar in size to gnathopod 1, not strongly sexually dimorphic; uropod 1 peduncle without basofacial spine(s), outer ramus distinctly shorter than inner ramus | 5 |
– | Gnathopod 2 larger than gnathopod 1, strongly sexually dimorphic; uropod 1 peduncle with basofacial spine(s), outer ramus subequal to or shorter than inner ramus | 8 |
5 | Antenna 1 accessory flagellum present (may be 1-articulate); telson lobes relatively narrow, apices acute or subacute (Fig. |
6 |
– | Antenna 1 lacking accessory flagellum; telson lobes relatively wide, apices rounded or subquadrate (Fig. |
7 |
6 | Antenna 1 accessory flagellum 1-articulate; gnathopods 1 and 2 propodus palmar margin lined with peg-like robust setae; epimeron 3 posterior margin serrate, posteroventral corner not produced; telson distinctly longer than wide, apices of lobes subacute (Fig. |
Eusiroides yucatanensis |
– | Antenna 1 accessory flagellum 5-articulate; gnathopods 1 and 2 propodus palmar margin lined with slender setae; epimeron 3 posterior margin smooth, posteroventral corner produced; telson slightly longer than wide, apices of lobes bifid and acute (Fig. |
Hornellia tequestae |
7 | Rostrum narrow, distally acute; epimeron 3 regularly serrate; telson cleft ~ ½ of length, lobes not narrowing distally; uropod 3 inner ramus slightly shorter than outer ramus (Fig. |
Nasageneia bacescui |
– | Rostrum wide, distally rounded; epimeron 3 smooth or with small serration; telson cleft ¾ of length, lobes narrowing distally; uropod 3 inner ramus subequal to outer ramus (Fig. |
Tethygeneia longleyi |
8 | Uropod 3 inner ramus minute (Fig. |
9 |
– | Uropod 3 rami subequal or slightly unequal in length (Figs |
12 |
9 | Gnathopod 2 of male, sides similar; posterodorsal margins of pleon segments 1–3 without serrations or teeth (Fig. |
10 |
– | Gnathopod 2 of male, sides dissimilar, significantly different in size, larger side chelate; posterodorsal margins of pleon segments 1–3 with serrations or teeth (Fig. |
11 |
10 | Coxa 6 of female anterior lobe with lateral ridge at base of hook; uropod 3 outer ramus 1-articulate (Fig. |
Melita planaterga |
– | Coxa 6 of female unmodified; uropod 3 outer ramus 2-articulate (Fig. |
Dulzura schoenerae |
11 | Gnathopod 2 distolateral crown with four rounded or subacute spines, 4th spine well developed, dactylus apically hooked, fitting into posterodistal corner; pereopods 6 and 7 carpus and propodus with bunches of long slender setae; epimeron 1 posteroventral corner subquadrate; epimeron 3 posterodistal margin smooth (Fig. |
Dulichiella lecroyae |
– | Gnathopod 2 propodus distolateral crown with three rounded indistinct spines, dactylus apically blunt, overlapping posterodistal corner; pereopods 6 and 7 carpus and propodus without bunches of long slender setae; epimeron 1 posteroventral corner acute; epimeron 3 posterodistal margin serrate (Fig. |
Dulichiella anisochir |
12 | Antenna 1 accessory flagellum 2- or 3-articulate; mandible, palp stout, article 3 falcate, with comb row of very short marginal setae; uropod 3 outer ramus < 3 × longer than wide (Fig. |
13 |
– | Antenna 1 accessory flagellum at least 4-articulate; mandible, palp slender, article 3 linear, without comb row of short marginal setae; uropod 3 outer ramus > 3 × longer than wide (Fig. |
18 |
13 | Pereopod 7 basis posterior margin with long setae (Fig. |
14 |
– | Pereopod 7 basis posterior margin without long setae | 15 |
14 | Male gnathopod 2 propodus elongate, palm with three teeth; epimeron 3, posteroventral margin serrate (Fig. |
Elasmopus longipropodus |
– | Male gnathopod 2 propodus subovate, palm with large excavation; epimeron 3, posteroventral margin with single acute tooth (Fig. |
Elasmopus pocillimanus |
15 | Gnathopod 2 propodus palm with few setae; telson inner lobes apically rounded (Fig. |
16 |
– | Gnathopod 2 propodus palm densely setose; telson inner lobes apically acute (Fig. |
17 |
16 | Male gnathopod 2 propodus palm concave with one triangular process; epimeron 3 posteroventral margin with small tooth; telson inner lobes subequal in length with outer lobes (Fig. |
Elasmopus elieri |
– | Male gnathopod 2 propodus palm with 3 processes and 2 notches; epimeron 3 posterior margin serrate; telson inner lobes longer than outer lobes (Fig. |
Elasmopus thomasi |
17 | Pereopod 5 basis posterior margin concave; telson inner lobes shorter than outer lobes (Fig. |
Elasmopus balkomanus |
– | Pereopod 5 basis posterior margin evenly convex; telson inner lobes subequal to outer lobes (Fig. |
Elasmopus levis |
18 | Mandible palp article 1 with small distal tooth; maxilla 2 inner plate with dense oblique row of facial setae; uropod 3 rami broad, foliaceous, tips subacute (Fig. |
19 |
– | Mandible palp article 1 without small distal tooth (Fig. |
20 |
19 | Male gnathopod 2 left and right sides dissimilar; pleon segments 1–3 posterodorsal margins without strong teeth or serrations; urosome segments 1 and 2 posterodorsal margins each with single tooth (Fig. |
Ceradocus shoemakeri |
– | Male gnathopod 2 left and right sides similar; pleon segments 1–3, posterodorsal margins with many strong teeth or serrations; urosome segments 1 and 2 posterodorsal margins with many strong teeth (Fig. |
Ceradocus sheardi |
20 | Eyes oval; gnathopod 1 carpus subequal to propodus, without dorsal excavation; gnathopod 2 propodus palm oblique; pereopods with simple dactyli; pereopod 7 basis slimmer than long, without posterodistal lobe (Fig. |
Meximaera diffidentia |
– | Eyes round; gnathopod 1 carpus longer than propodus, with dorso-distal excavation; gnathopod 2 propodus palm with right angle; pereopods with bifid dactyli; pereopod 7 basis as slim as long, with posterodistal lobe (Fig. |
21 |
21 | Male gnathopod 2 propodus palm with deep excavations, palmar angle defined by elongate process below deep U-shaped notch (Fig. |
22 |
– | Male gnathopod 2 propodus palm with shallow excavations, palmar angle defined by short process below shallow V-shaped notch (Fig. |
24 |
22 | Gnathopod 2 dactyl inner margin smooth in males and females; telson lobes apically truncate (Fig. |
23 |
– | Gnathopod 2 dactyl inner margin inflated in males and females; telson inner lobes inner corner acutely produced (Fig. |
Quadrimaera cristianae |
23 | Gnathopod 1 propodus palm with short-to-medium setae; gnathopod 2 propodus palm with two large U-shaped excavations; telson with lateral plumose setae (Fig. |
Quadrimaera quadrimana |
– | Gnathopod 1 propodus palm with long setae; gnathopod 2 propodus palm with one large and two small excavations; telson without lateral setae (Fig. |
Quadrimaera yemanjae |
24 | Gnathopod 2 propodus palm transverse with central U-shaped concavity and subquadrate/quadrate processes, dactylus strong, medially expanded (Fig. |
Quadrimaera sarae |
– | Gnathopod 2 propodus palm transverse with smaller, deeper concavity and broad processes; dactylus not strong (Fig. |
25 |
25 | Gnathopod 2 dactylus inner margin inflated with median point (Fig. |
Quadrimaera miranda |
– | Gnathopod 2 dactylus inner margin inflated without median point (Fig. |
Quadrimaera ceres |
The results of this study represent range extensions for 26 species of hadziidirid amphipods to include Caribbean waters of Panama. Several species have a distribution pattern spanning the eastern Pacific and western Caribbean (Elasmopus pocillimanus, Meximaera diffidentia, Quadrimaera quadrimana, Gibberosus devaneyi, and Gibberosus myersi). Without examining material from every collection, it is impossible to be sure the species in the literature were identified correctly or if the specimens may represent a different species. Assuming proper identification, these distribution patterns may suggest that the species were established more than 3 mya, before the isthmus of Panama closed.
Several hadzidiiran species demonstrate variation in key characters or are identified based on males only. Several Elasmopus species are differentiated based on epimeron 3 serration patterns and the apices of telson lobes, both of which can vary among individual specimens. As discussed by
Logistical support and facilities were provided by Georgia College & State University Department of Biological and Environmental Sciences and the Smithsonian Tropical Research Institute (STRI). Special thanks to Carolina Cesar and Valentina Cardona for assistance with diving and collecting in Bocas del Toro. The authors also wish to thank Dr. Lauren Hughes and the Amphipod Taxonomy Course members for their collecting assistance in 2023. Special thanks go to Sara LeCroy for her loan of specimens collected in 2005.
The authors have declared that no competing interests exist.
No ethical statement was reported.
Funding for this study was provided by a National Science Foundation grant: Collaborative Research: ARTS: Understanding Tropical Invertebrate Diversity Through Integrative Revisionary Systematics and Training (1856421). Publication costs were provided by a GC Journeys mini-grant from Georgia College & State University.
Conceptualization: KNW. Data curation: KNW. Formal analysis: SJS, KNW. Funding acquisition: KNW. Investigation: SJS, KNW. Project administration: KNW. Supervision: KNW. Writing - original draft: KNW. Writing - review and editing: SJS, KNW.
Kristine N. White https://orcid.org/0000-0002-5203-1656
Sally J. Sir https://orcid.org/0000-0002-1270-1192
All of the data that support the findings of this study are available in the main text or Supplementary Information.
Locality table
Data type: xlsx