Anapronoe Stephensen, 1925

Zeidler, Wolfgang, 2016, A review of the families and genera of the superfamily PLATYSCELOIDEA Bowman & Gruner, 1973 (Crustacea: Amphipoda: Hyperiidea), together with keys to the families, genera and species, Zootaxa 4192 (1), pp. 1-136 : 57

Genus Anapronoe Stephensen, 1925

( Figs 23–25 )

Anapronoe Stephensen, 1925: 163 .— Spandl 1927: 216 (key), 217.— Bowman & Gruner 1973: 45.— Vinogradov et al. 1982: 380.— Shih & Chen 1995: 168.— Zeidler 1997b: 139.— Vinogradov 1999: 1193.

Type species. Anapronoe reinhardti Stephensen, 1925 by monotypy. The unique male holotype is in the ZMUC (CRU-439) ( Zeidler 1997b). The type locality is the tropical Atlantic between Brazil and West Africa [05°31’N 23°15’W], coll. J.Th. Reinhardt, depth and date of collection unknown.

Diagnosis. Body shape robust or globular. Head rounded. Eyes occupying most of lateral head surface; grouped in one field on each side of head. Antenna 1 of male with 3-articulate peduncle; flagellum with large, crescent-shaped callynophore, with aesthetascs arranged in one-field brush medially; with three smaller articles inserted on antero-dorsal corner. Antennae 1 of females with 3-articulate peduncle; callynophore narrowly rectangular, with two smaller articles inserted terminally. Antennae 2 present in both sexes; inserted on ventral surface of head in groove across head. Antennae 2 of males 6-articulate; zig-zagged, but only proximal three articles folded back on each other; terminal three articles not folded, pointing anteriorly. Antennae 2 of females 5- articulate, not folded, terminal article very short. Mandibular incisor relatively broad, with several teeth, with small distal lobe medially; in male orientated more or less parallel to palp. Maxillae 1 consisting of elongate, plate-like lobes, with four bifid teeth terminally on medial margin. Maxillae 2 bi-lobed, with two terminal teeth or robust setae on each lobe. Maxilliped with inner lobes completely fused; medial margin of outer lobes with membranous fringe. Gnathopod 1 sub-chelate; carpal process more or less produced, rounded, armed with microscopic teeth or setae; basis triangular with very broad distal margin, slightly wider than twice merus. Gnathopod 2 chelate; carpal process spoon-shaped, with rounded, or pointed, postero-distal corner, relatively smooth or armed with small teeth or setae; basis rectangular, very broad, slightly wider than twice merus. Pereopods 3 & 4 sub-equal in length to pereopods 5 & 6. Pereopod 5; basis with medial bulge on anterior margin, about 4 x as wide as wide as merus, nonlocking but may overlap with P6; articles 3–7 inserted terminally to basis. Pereopod 6; basis very broad proximally, more than 6 x as wide as merus, but not operculate, does not overlap, or lock, with opposing pereopod; articles 3–7 inserted sub-terminally on basis. Pereopod 7 reduced in size with basis not particularly enlarged; all articles present; dactylus normal, sometimes hooked. Uropoda normal, all with articulated exopoda and endopoda, all lanceolate, usually with serrated margins.

Species. Anapronoe reinhardti Stephensen, 1925 and A. bowmani Zeidler, 1997 .

Sexual dimorphism. The sexes are remarkably similar in gross morphology, differing mainly in the morphology of the antennae and the mandibles.

Remarks. Specimens of Anapronoe are very rare in plankton collections of the world. Material has been collected from the warm-temperate to tropical regions of the world’s oceans, via vertical hauls from great depths (1000–0 m, 1500–0 m, 3000–0 m). Considering its rarity, one might speculate that Anapronoe is a deep-water genus, but other material was collected near the surface.

Nothing is known regarding the biology of species and the only record of an association with gelatinous plankton is for A. reinhardti from an undescribed physonectid siphonophore ( Gasca et al. 2006, 2014), but listed as Resomia ornicephala by Gasca et al. (2014) in their table.

Zeidler (1997b) redescribed A. reinhardti and described one additional species as new to science.

Figures

FIGURE 23. A, Anapronoe bowmani Zeidler, 1997, habitus of holotype female (6.8 mm), N. E. Pacific, off California, USNM 278109. Anapronoe reinhardti Stephensen, 1925; B, C, ventral and lateral view of head of female (7.4 mm), Caribbean Sea, USNM 278108 (also A 1 & 2, Us); antennae from male (7.9 mm), N. E. Pacific, off California, USNM 278107. Scale bars = 0.5 mm (B, C, Us), 0.2 mm (antennae).

FIGURE 24. Anapronoe reinhardti Stephensen, 1925, female (7.4 mm), Caribbean Sea, USNM 278108. Scale bar = 0.2 mm.

FIGURE 25. Anapronoe reinhardti Stephensen, 1925, male (7.9 mm), N. E. Pacific, off California, USNM 278107. A, ventral view of head showing antennal grooves; B, lateral view of head; C, lateral view showing buccal mass and antennal groove, with antennae removed. Scale bars = 0.5 mm (A – C), 0.1 mm (remainder).