Odontodactylus latirostris Borradaile, 1907

Brokensha, Rouane, Landschoff, Jannes & Griffiths, Charles, 2023, New and notable stomatopods (Crustacea, Stomatopoda) from Mozambique, European Journal of Taxonomy 900 (1), pp. 148-179 : 168-170

Odontodactylus latirostris Borradaile, 1907 new record

Fig. 10

Odontodactylus latirostris Borradaile, 1907: 212 , pl. 22 figs 3, 3a [type locality Amirante Islands, Seychelles].

Odontodactylus southwelli Kemp, 1911: 94 [type locality Andaman Island].

Odontodactylus southwelli Kemp 1913: 142 , pl. 9 figs 103–106.

Odontodactylus latirostris – Debelius 1999: 280–281. — Ahyong 2001: 83–85, fig. 40. — Ahyong et al. 2020: 6 [chart].

non Odontodactylus japonicus – Stephenson 1962: 35 [not Odontodactylus japonicus (de Haan, 1844) ].

non Odontodactylus brevirostris – Manning 1967b: 23. — Moosa 1991: 161–162 [not O. brevirostris ( Miers, 1884)].

Diagnosis

Ocular scales separated by deep concavity, margins truncate. A2 scale posterior and at most anterior distal 0.33 setose in smallest specimens; anterior setae becoming reduced with size, absent in adults. Rostral plate ovoid, apex rounded. Raptorial claw dactylus with 7 or 8 teeth on inner margin. TS6– 7 lateral margins rounded, that of TS6 slightly broader and flatter than that of TS7. AS (4)5 with posterolateral spine. Telson mid-dorsal surface with distinct MD carina and 2 longitudinal carinae either side of midline (accessory MD; anterior SM) in addition to carinae of primary teeth. Uropodal exopod proximal segment entirely, or almost entirely, black, outer margin with 9 or 10 movable spines; exopod distal segment subequal to or longer than proximal segment; endopod with 2 subequal dorsal carinae and 1 ventral carina.

Material examined

MOZAMBIQUE • 1 ♁ (TL 52 mm); Maputo Bay ; 26°04′58.1″ S, 32°45′47.9″ E; depth unknown; 1–7 Nov. 1900; R. Trott leg; SAMC – A079415 .

Colour in alcohol

Base dorsal colour dark brown, but with faint blue colouration laterally on carapace and posterior margin of abdominal somites. Definite suggestions of blue distal colouration on all primary teeth of telson and on movable spines of exopod proximal segment. Uropod with black band across proximal segment of exopod, adjacent to protopod and endopod.

Colour in life

Overall colour is a mottled light brown on white-cream, with darker brown mid-dorsal surface of TS6–7 white with tan-brown mottling dorsally. Uropod with black band across proximal segment of exopod, adjacent protopod and endopod; exopod distal segment and A2 scale pink ( Ahyong 2001).

Measurements

Male (n = 1) TL 52 mm. Uropodal exopod distal segment length 1.05 times proximal segment length. The largest known specimen at TL 77 mm reported from Western Australia ( Ahyong 2001).

Distribution

Amirante Islands to Andaman Sea, Indonesia, New Caledonia, Australia, and now southern Mozambique [Maputo]; depths previously recorded between 20 and 147 m.

Remarks

Morphologically the Mozambican specimen agrees well with Ahyong’s (2001) account, as well as his designated lectotype [locality Amirante Islands, Seychelles; TL 53 mm]. Odontodactylus latirostris is one of three species, together with O. hawaiiensis and O. hansenii ( Pocock, 1893) , that were removed from synonymy with O. brevirostris ( Miers, 1884) by Ahyong (2001). Odontodactylus latirostris is distinguished from these other similar species in the ‘ brevirostris complex’ in having reduced setation of the anterior margin of the antennal scale, by the absence of a posterolateral spine on AS 3, as well as an almost entirely, or entirely, black proximal segment of the uropodal exopod and in having the distal segment exceed in length the proximal segment of the uropodal exopod.

Some allometric variation has been recorded in the degree of antennal scale setation, the presence of a posterolateral spine on AS 4 (missing in large specimens) and the relative lengths of the uropodal exopod segments. In juvenile specimens (TL 17 mm) the antennal scale was fully setose, while in larger specimens only posteriorly setose ( Ahyong 2001). As specimens grow larger, the uropodal exopod distal segment increases in relative size and can be shorter than the proximal segment in juveniles and only subequal in length in midrange specimens (TL 45 mm) to distinctly longer in large specimens ( Ahyong 2001). The present specimen (TL 52 mm) from Maputo Bay, Mozambique, exhibited the typical O. latirostris antennal setation; only posterior setose present with anterior setae absent ( Fig. 10B ). Furthermore, the posterolateral spine was present on AS 3 and the relative lengths of the proximal and distal segments of the uropodal exopod were subequal with the distal segment only slightly longer than the proximal ( Fig. 10E–F ). The dactylus of the raptorial claw has eight teeth and the outer margin of the uropodal exopod proximal segment shows ten movable spines ( Fig. 10F ).

However, live colour according to Ahyong (2001) only partly agrees with the observations of the Mozambican specimen presented herein and no other documentation of live colouration is available. According to the lectotype designated by Ahyong (2001), no blue colouration is recorded for the species. As the present study only examined preserved material it is possible that the blue tint is due to some unknown discolouration since its collection in 1900.

Figures

Fig. 10. Odontodactylus latirostris Borradaile, 1907, ♂, TL 52 mm (SAMC–A079415). A. Anterior cephalothorax, dorsal. B. Right antennal scale, dorsal. C. AS4–5, left lateral. D. TS8 sternal keel, left lateral. E. AS5–6, telson and right uropod, dorsal. F. Right uropod, ventral. Scale bar = 5 mm.