Odontodactylus hansenii ( Pocock, 1893 )

Odontodactylus hansenii ( Pocock, 1893) , new record

( Fig. 11 View FIGURE 11 )

Gonodactylus hansenii Pocock, 1893: 473–479 , pl. 20.B, fig. 3 [ type locality Macclesfield Bank, South China Sea]. Odontodactylus hansenii . — Manning, 1967c: 4–5 (text).—Ahyong 2001: 78–79.— Ahyong 2002b: 829.— Poupin, 2010: 59,

76.

Material examined. KZN: SAMC-A079452 , 1 ♂ (TL 37 mm), Sodwana Bay, 27°31.8’S 32°42.8’E, 2 June 1990, 70 m, Natal Museum Dredging Programme, stat. ZH 18 GoogleMaps ; SAMC-A079453 , 1 ♀ (TL 60 mm), off ‘ Dog Pond’ Kosi Bay, 27°06’00.0”S 32°53’17.9”E, 74 m, stat GoogleMaps . ZC 10 , dredge .

Diagnosis. Ocular scales separated by deep concavity, margins truncate. A2 scale anterior margins setose, distal setae present or becoming reduced in size. Rostral plate ovoid, apex rounded. Raptorial claw with 8 or 9 teeth on inner margin. TS6–7 lateral margins rounded. AS (3)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. Uropod exopod proximal segment entirely or almost entirely black, outer margin with 11 movable spines; exopod distal segment distinctly shorter than proximal segment; endopod with 2 subequal dorsal carinae and 1 ventral carina.

Colour in alcohol. Almost completely faded except for a dark, transverse patch mid-dorsal on the carapace; the distinctive uropod exopod proximal segment entirely or almost entirely black. Dark mottled speckles on posterior margin of AS 1; all primary teeth of telson with some dark brown colouration.

Colour in life. A previous note describes a live specimen with ‘telson pink, eyes apple green, dorsum rusty, mottled’ ( Bigelow 1931). More recently, a colour photograph of a specimen from Réunion shows the dorsum to be mottled rust, yellow and orange ( Legall & Poupin 2022).

Measurements. ♂ (n = 1) TL 37 mm, ♀ (n = 1) TL 60 mm. Largest specimen recorded by Ahyong (2002b) for a TL 77 mm specimen.

Distribution and habitat. Indo-West Pacific. South China Sea, Japan, Philippines, New Caledonia, Hawaii, Réunion and now from South Africa [KZN]; 70– 74 m. Associated with rock and rubble substrata, recorded depths 20– 324 m.

Remarks. Odontodactylus hansenii is a warm water species known from South Africa only by the present specimens from KwaZulu-Natal. Unfortunately, no male specimen from South African waters was available for examination. This species has ‘small’ post larvae and have well-developed telson carinae by TL 25 mm (Ahyong 2001).

Formerly thought to be a synonym of O. brevirostris by Manning (1967c), O. hansenii is now considered distinct (Ahyong, 2001). Previously, O. havanensis , O. hansenii and O. latirostris were often misidentified as O. brevirostris . The four species belong to a group referred to as the ‘ O. brevirostris complex’. To help resolve this group, Ahyong (2001) suggested the use of characters such as extent of antennal scale setation and colouration, presence of AS 3 posterolateral spine and relative length of uropodal exopod proximal segment, as well as overall colour. Similar Odontodactylus species share a single accessory MD carina either side of the MD carina of the telson and AS 3–5 posterolaterally spined. Odontodactylus hansenii is distinguished from these similar species by the uropodal exopod distal segment being shorter than the proximal segment and the uropodal exopod proximal segment coloured completely black (Ahyong 2001). Ahyong (2001) gives a preliminary key to the species of Odontodactylus but stresses the continuation of study and re-examination of specimens for species within the ‘ O. brevirostris complex’.