Podocerus offucia, Sir & White, 2025

Podocerus offucia sp. nov.

Figs 26 View Figure 26 , 27 View Figure 27 , 28 View Figure 28 , 33 B View Figure 33

Type locality.

Bocas del Toro, Panama: Swan Cay, 9.4536°N, 82.3000°W, among coral rubble.

Material examined.

Holotype: Panama • 2.8 mm • 1 ♂; Bocas del Toro, Panama: Swan Cay , 9.4536°N, 82.3000°W, depth 1–3 m; among coral rubble; 27 June 2023; K. N. White leg; USNM 1743973 About USNM GoogleMaps . Paratype: Panama • 2.8 mm • 1 ♀; station data same as holotype; USNM 1743974 About USNM GoogleMaps .

Diagnosis.

Pereon segments 5–7 dorsally setose. Male antenna 1 flagellum 4 - articulate; accessory flagellum uni-articulate. Coxa 1 with four marginal setae. Gnathopod 1 basis slender. Male gnathopod 2 propodus palm serrate with one large, rounded projection, posteriorly concave. Pereopods 3–7 propodus with posterodistal notch. Uropods 1 and 2 each with distoventral interramal spine.

Description.

Male (holotype, 2.8 mm). Head. Eyes round, bulging. Antenna 1 densely setose, flagellar article 1 shorter than flagellar article 2; accessory flagellum uni-articulate. Antenna 2 densely setose; flagellum 4 - articulate. Maxilliped inner plate with seven plumose apical setae, outer plate lined with ten marginal robust setae and many facial setae, palp 4 - articulate. Lower lip missing. Maxilla 1 inner plate absent; outer plate with six apical robust setae; palp bi-articulate, apical margin with four bifurcate setae and three slender setae. Maxilla 2 inner and outer plate apical margins lined with setae; outer plate with two rows. Mandibular palp tri-articulate, lined with plumose setae. Upper lip missing.

Pereon. Pereon segments with posterodorsal processes. Pereonites 5–8 with dorsal robust setae. Coxae sparsely setose, discontiguous. Coxa 1 rhomboidal. Gnathopod 1 subchelate; basis slender; ischium posterior margin with two long setae; merus posterior margin with long plumose setae; carpus longer than wide, posterior margin lined with plumose setae, with two plumose facial setae; propodus subequal in length with carpus, posterior margin with many simple and plumose setae, anterolateral margin with facial setae; dactylus inner margin serrate. Gnathopod 2 subchelate, much larger than gnathopod 1; basis expanded anteriorly into rounded process, posterior margin with short setae; ischium posteriodistal margin with sparse short setae; merus ventral margin lined with long slender plumose setae and two short, stout setae; carpus reduced, ventral margin lined with long slender plumose setae; propodus palm serrate with one large, rounded projection, posteriorly concave; dactylus closing on concavity. Pereopods 3–6 missing. Pereopod 7 basis ovate; ischium short; merus posteriorly expanded; propodus with posterodistal notch.

Pleon. Epimera 1–3 with posterodorsal processes; posteroventral margins smooth, rounded. Uropod 1 1.4 × length of uropod 2; peduncle with distoventral interramal spine, apical margin with one slender seta; inner ramus 2.3 × length of peduncle, outer margin lined with robust setae and fine setules, apical margin with one long seta; outer ramus outer margin with few robust setae, apical margin with one long seta. Uropod 2 peduncle with distoventral interramal spine, apical margin with one slender seta; inner ramus 2.9 × length of peduncle, outer margin lined with robust setae and fine setules, apical margin with one long seta; outer ramus outer margin with one robust seta, apical margin with one long seta. Uropod 3 vestigial, rounded. Telson dorsally produced, with two long and two short setae.

Female (paratype, 2.8 mm). Similar in all aspects to the male with the exception of the following: Antenna 1 flagellum tri-articulate. Lower lip outer lobes rounded, setose; mandibular lobes acutely pointed. Gnathopod 2 basis stout, without rounded process, posterodistal margin with one seta; merus rounded posteriorly, with distal robust seta and several slender setae; carpus subtriangular; propodus enlarged, rounded, palmar margin smooth, moderately setose, with two large setae; dactylus inner margin with short setae. Pereopods 5 and 6 anterior and posterior margins of most articles with plumose setae; propodus posterodistal margin with notch.

Etymology.

After the Latin offucia, meaning paint or wash for face and referring to dark pigment on the head of this species.

Distribution.

Panama: Bocas del Toro (present study).

Ecology and remarks.

These amphipods occur among coral rubble, occurring with other Podocerus species at depths of 1–3 m. Podocerus offucia sp. nov. is most similar to Podocerus lazowaemi Baldinger & Gable, 1994 in sharing the following characters: male antenna 1 flagellum 4 - articulate, accessory flagellum uni-articulate; gnathopod 1 basis slender; and uropods 1–2 each with distoventral interramal spine. The new species differs in the following characters: antenna 2 flagellum 4 - articulate (vs 5 - articulate), coxae 1 with four setae (vs 1 robust seta), coxa 2 bare (vs 1 robust seta), pereopods 3–7 propodus with posterodistal notch (vs lacking). Podocerus offucia sp. nov. is also similar to Podocerus kleidus Thomas & Barnard, 1992 in the presence of interramal spines on uropod 1 and 2 but differs in the following characters: antenna 1 flagellum 3 or 4 - articulate (vs 6 - articulate), coxa 1 entire (vs cleft), and four robust setae on telson (vs 9 robust setae). Podocerus offucia sp. nov. can be easily distinguished from all remaining described Podocerus species based on having dorsal setae only on pereon segments 5–7, the shape of male gnathopod 2 propodus, and having uropods 1 and 2 each with distoventral interramal spine. Ethanol-preserved specimens of the new species retained purple-brown coloration on the head with faint coloration on the pereon.