Podocerus cf. crenulatus Myers, 1985

Hughes, L. E., 2013, Podoceridae of Tropical Australia (Peracarida: Amphipoda), Records of the Australian Museum 65 (1), pp. 1-37 : 9

Podocerus cf. crenulatus Myers, 1985

Fig. 7

Podocerus crenulatus Myers, 1985: 60 , fig. 44.—Kilgallen, 2009: 850–853, figs 6, 7.

Type locality. Momi Bay , Viti Levu, Fiji.

Material examined. Australia. Male , 3.0 mm, dissected, 2 slides, MAGNT Cr 017401, south end of lagoon, Scott Reef , Indian Ocean (14°01'S 121°47'E), intertidal pools, dead coral rubble and sand, 18 September 1984, coll: B. Russell. Fiji. Holotype male, 2.7 mm, AM P.35190, Momi Bay, Viti Levu, 7 September 1979, coll. A. A. Myers.

Diagnosis. Body laterally rugose. Head with weak hump. Gnathopod 2 propodus medial surface with sparse setae, 3⁄4 the length of the propodus, palm with one distal subtriangular tooth, palm defined by 2 robust seta without corner or tooth. Pereonite 7 with lateral hump. Pleonite 1 dorsal carina narrow, produced posteriorly, subtriangular, apically rounded, with lateral hump. Pleonite 2 dorsal carina broad, produced posteriorly, subtriangular, apically rounded, with lateral hump. Uropod 1 with well-developed ventromedial spine, spine twice as long as broad.

Description. Based on male, 3.0 mm, Cr017401. Body cuticle with posterior dorsal carinae, laterally rugose. Head with weak hump; rostrum short, about 1 tenth of head length; eyes greatly bulging; lateral cephalic lobe rounded; anteroventral corner subquadrate. Mandible accessory setal row with 3 setae. Maxilla 1 palp distal margin with 6 robust setae.

Gnathopod 1 coXa damaged; basis 3 times as long as broad, without anterodistal setae; carpus rectolinear, 2.1 times as long as broad with truncate lobe; propodus subrectangular, anterior margin with sparse slender setae, palm margin minutely crenulate, without robust seta at corner of palm; dactylus posterior margin with serrate teeth, cuticle surface with raised serrations. Gnathopod 2 basis twice long as broad; anterodistal corner with produced subacute lobes, with long slender setae; merus posterior margin with narrow produced lobe, lobe twice as long as broad, posterior margin apically rounded, with 2 short robust setae; carpus free, distinct from propodus; propodus elongate subovoid, length 2.1 times width, anterior margin with clusters of long slender setae, medial surface with sparse setae, palm acute, straight, 3⁄4 the length of the propodus, with broad, well developed distal shelf, shelf margin smooth, palm with one distal subtriangular tooth, palm defined by 2 robust seta without corner or tooth; dactylus closing along palm. Pereonite 6 dorsal carina narrow, produced posteriorly, subtriangular, apically rounded. Pereonite 7 dorsal carina broad, produced posteriorly, subtriangular, apically rounded, with lateral hump.

Pleonite 1 dorsal carina narrow, produced posteriorly, subtriangular, apically rounded, with lateral hump. Pleonite 2 dorsal carina broad, produced posteriorly, subtriangular, apically rounded, with lateral hump. Epimera 1–3 posteroventral corner rounded. Urosomite 1 twice as long as broad. Uropod 1 peduncle 3 times as long as broad, with well-developed ventromedial spine, spine twice as long as broad; inner ramus 1.3 times peduncle length; outer ramus about 3⁄4 the length of the inner ramus. Uropod 2 biramous; peduncle ventromedial spine absent; outer ramus about half the length of inner ramus. Uropod 3 uniramus; rami without setae. Telson dorsal lobe with 2 apical setae, lower margin without lateral or apical setae.

Remarks. This single male specimen from Scott Reef is attributed to P. crenulatus Myers, 1985 originally described from Viti Levu, Fiji. The Scott Reef specimen has a more elongate pereonite 6 and has a smooth, not crenulate, palm of gnathopod 2. The Scott Reef specimen is larger 3.0 mm than those figured from Fiji, 2.7 mm ( Myers, 1985) and Queensland, 2.0 mm (Kilgallen, 2009). The gnathopod crenulations may not persist in larger adult male forms, or the single specimens here may be an aberration. The male specimens from Fiji have an extra robust setae on the gnathopod 2 propodus between the distal shelf and first palmar tooth, not seen in this specimen.

Distribution. Australia. Indian Ocean: Scott Reef (current study). Queensland: Lizard Island (Kilgallen, 2009). Fiji: Viti Levu ( Myers, 1985).

Figures

Figure 7. Podocerus cf crenulatus, Myers, 1985, male, 3.0 mm, MAGNT Cr017401, Scott Reef, Indian Ocean (scale 0.1 mm).