Nasutoplax rostrata (Haswell, 1881) Haswell, 1881

Poore, Gary C. B., Guinot, Danièle, Komai, Tomoyuki & Naruse, Tohru, 2016, Reappraisal of species attributed to Halicarcinus White, 1846 (Crustacea: Decapoda: Brachyura: Hymenosomatidae) with diagnosis of four new genera and one new species from New Ireland, Papua New Guinea, Zootaxa 4093 (4), pp. 480-514 : 507

Nasutoplax rostrata (Haswell, 1881) n. comb.

( Fig. 11 )

Hymenosoma rostratum Haswell, 1881: 550 . — Haswell 1882: 116. — Baker 1906: 114, pl. 3 fig. 2. — Kemp 1917: 247. Halicarcinus rostratus— Hale 1927: 117–118, fig. 114. — Griffin & Yaldwyn 1971: 46. — Griffin 1972: 65. — Lucas 1972: 475–

482, figs 3H, 5A–D (larva). — Lucas 1980: 180–181, figs 3F, 6L, 7F, 10H. — Poore 2004: 394, fig. 120d. Rhynchoplax rostrata— Tesch 1918: 17, 18.

Neorhynchoplax rostrata— Takeda & Miyake 1971a: 160.

Material examined. Australia. Victoria, Geelong, Wheat and Rippleside piers, 38°07'S, 144°22'E, NMV J65981 (1 male, cl 5.0 mm), NMV J64928 (2 ovigerous females, 4.2 mm)—selected from many hundreds of specimens in NMV collections.

Diagnosis. As for genus.

Distribution. Southern Australia, soft sediments, 2–130 m (Poore 2004).

Remarks. Baker’s (1906) and Hale’s (1927) descriptions and figures characterise the species well, showing the rostrum in dorsal view, and carinate propodus and carpus of the male cheliped. Neither author noted the unique lateral profile of the rostrum (fig. 11b, k). The median rostral lobe is laterally flattened, distally upturned and with a secondary lower apex, more prominent in males than in females. The rostrum is shorter in females than in males. Lucas (1980) did not remark on the unusual spinulose lobe near the apex of gonopod 1 that sets the species apart from all other hymenosomatids. The cornea is curved upwards from the eyestalk and more erect than in other taxa. Nasutoplax rostrata is very common in southern Australian muddy environments. Ovigerous females carry about 50 embryos, each 0.3 mm diameter.

Figures

FIGURE 11. Nasutoplax rostrata (Haswell, 1881). Male, cl 5.0 mm, NMV J 65981: a, rostrum, eyestalks, antennules and antennae, dorsal view; b, anterior carapace, eyestalks, antennules and antennae, left lateral view; c, rostrum, eyestalks, antennules, antennae, epistome, ventral view; d, rostrum to thoracic sternum, ventral view; e, left cheliped, carpus, propodus and dactylus, lateral view; f, pereopod 2 (no setae shown); g, left gonopod 1, lateral view; h, left gonopod 1 apex, mesial view (magnified); i, gonopod 2. Female, cl 4.2 mm, NMV J 65928: j, rostrum, eyestalks and antennae; k, anterior carapace, eyestalk, antennule and antennae, right lateral; l, right thoracic sternites 7, 8, lateral margins of pleomeres 1, 2 (branchiosternal canal aperture shown). Scale bars = 1 mm.