Erugosquilla woodmasoni ( Kemp, 1911 )

Brokensha, Rouane, Landschoff, Jannes & Griffiths, Charles, 2023, New and notable stomatopods (Crustacea, Stomatopoda) from Mozambique, European Journal of Taxonomy 900 (1), pp. 148-179 : 159-161

Erugosquilla woodmasoni ( Kemp, 1911)

Fig. 6

Squilla wood-masoni Kemp, 1911: 99 ; 1913: 74–76, pl. V figs 63–65 [type locality Madras, India, by lectotype selection ( Ahyong 2001)].

Oratosquilla tweediei Manning, 1971: 11–14 , fig. 4 [type locality Singapore].

Oratosquilla jakartensis Moosa, 1975: 13–17 , fig. 1 [type locality Jakarta Bay, Indonesia].

Squilla wood-masoni – Stephenson 1952: 5–6. — Stephenson & McNeill 1955: 243–244 (part).

Squilla woodmasoni – Stephenson 1953: 42. — Barnard 1962: 244 (list). — Manning 1966: 100–101, fig. 5.

Oratosquilla woodmasoni – Manning 1971: 11; 1978: 36–39, figs 21–22; 1991: 12–13. — Cannon et al. 1987: 63.

Erugosquilla woodmasoni – Manning 1995: 200–204, pl. 36 figs 123b, 124–126, 136k–m. — Ahyong & Manning 1998: 661. — Ahyong 2001: 251–253, fig. 123. — Liu 2008: (list).

Diagnosis

Ophthalmic somite anterior margin broadly rounded, with median spinule. A1 somite dorsal processes with obtuse apices, directed anterolaterally. Rostral plate short, broader than long, subtrapezoid. Raptorial claw dactylus with 6 teeth; merus outer inferodistal angle acutely angled or produced to a spine. Abdominal spination as follows SM (4)5–6, IM 3–6, LT 2–6, MG 1–5. Telson MD carina not flanked by rows of tubercles; prelateral lobe length subequal to margin of LT tooth; denticles SM 2–4, IM 7–10, LT 1. Uropodal protopod terminal spines with lobe on outer margin of inner spine rounded to spiniform; exopod proximal segment outer margin with 7–10 movable spines.

Material examined

MOZAMBIQUE • 1 ♂ (TL 119 mm); Mozambique Channel ; 19°49′00.0″ S, 36°05′00.0″ E; 54 m depth; 14 Jun. 1994; RV Algoa Mozambique SCAD survey; bottom trawl; SFI; SAMC – A04171 • 1 ♂ (TL 115 mm); Mozambique Channel ; 17°56′00.0″ S, 37°42′00.0″ E; 65 m depth; 17 Jun. 1994; RV Algoa Mozambique SCAD survey; bottom trawl; SFI; SAMC – A041709 .

Colour in alcohol

Mostly faded, but with definite hints of overall grey-green colouration. Carinae and grooves of carapace, SM and IM carinae of body all dark. A1 distal segments dark maroon in colour on outer margin. Posterior margins of body somites purple. Telson with MD carina and carinae of primary teeth maroon. Uropodal protopod spine appearing dark purple and endopod almost completely dark distally; distal half of proximal segment of exopod and inner half of distal segment dark.

Colour in life

Overall body colour is generally a uniform pale grey-green, but some specimens bear diffuse concentrations of chromatophores mid-dorsally on the abdominal somites, giving a slightly mottled to somewhat banded appearance. Mid-dorsal surface of telson maroon. Uropodal exopod blue; distal segment dark blue medially, pale blue or clear laterally. A2 protopod red to maroon ( Ahyong 2001).

Measurements

Male (n = 2) TL 115–119 mm. CI 363–369. A1 peduncle 0.93–0.98CL. A2 scale 0.66–0.70CL. Largest specimen known at TL 153 mm from Australia ( Ahyong 2001).

Distribution and habitat

Indonesia, Vietnam, Philippines, Taiwan, Japan and Australia to Western Indian Ocean and now confirmed from Mozambique [Sofala and Zambezia]. Associated with level habitats usually on sandy mud substrates and in sheltered coastal areas; 20–93 m depth.

Remarks

The present specimens represent the first verifiable record of E. woodmasoni from the Mozambique Channel. Previously, Barnard (1962) examined a specimen of E. woodmasoni collected from Inhaca Island, Maputo Bay, by Dr W. Macnae and Mrs M. Kalk, University of Witwatersrand. However, Barnard’s (1962) listing included no account of the specimen, or justification of the identification, giving only the species name and named location. As Barnard supplied so little information and no mention or documentation of the record is found in any other relevant literature, an account of E. woodmasoni from Mozambican waters is given here.

The specimens examined fall within the range of morphological variation documented in Ahyong’s (2001) recent account of the species from Australia. In one specimen, the anterior bifurcation of the median carina of the carapace is faintly visible, while in the other it is completely absent ( Fig. 6B ). Both Mozambican specimens exhibited the median spinule on the anterior margin of the ophthalmic somite, but this feature has been found to be absent in previous descriptions of the species ( Ahyong 2001). The shape of the outer inferodistal angle of the merus of the raptorial claw has been recorded to vary from acute to forming a spine, while the specimens examined here both showed acutely angled outer inferodistal angles of the merus ( Fig. 6A ). The lobe between the spines of the uropodal protopod can be triangular, but the Mozambican material showed a more rounded lobe ( Fig. 6F ). Ahyong (2001) lists some specimens of E. woodmasoni from Australia and Malaysia with armed SM carina on AS 4, but most agree with the present study material and have spines on the SM carinae of AS 5–6 ( Fig. 6G ).

Erugosquilla woodmasoni can be distinguished from all other species in the genus by the broad and rounded shape of the anterior margin ophthalmic somite and the acutely shaped outer inferodistal margin of the merus of the raptorial claw. Both features have been previously recorded to vary. However, the anterior margin of the ophthalmic somite is trapezoid to broadly triangular and the outer inferodistal margin of the merus of the raptorial claw is obtusely angled in other species of Erugosquilla . Otherwise, the present study material agrees in all features and measurements with previous accounts ( Manning 1995; Ahyong 2001), with 3 SM and 9 and 10 IM telson denticles and 9 movable spines on the outer margin of the uropodal exopod proximal segment. Moreover, at 54 m and 65 m the present specimens represent the deepest collection record of the species. Manning (1995) records the greatest abundance of the species from shallow depths of 15–25 m in Cauda and Nha Trang Bays, Vietnam. Ahyong (2001) documents specimens found in the shore to around 50 m which most closely resembles the depth distributional recorded herein.

Figures

Fig. 6. Erugosquilla woodmasoni (Kemp, 1911). A, D. ♂, TL 115 mm (SAMC–A041709). B–C, E–G. ♂, TL 119 mm (SAMC–A041711). A. Left raptorial claw, lateral. B. Anterior cephalothorax, dorsal. C. TS8 sternal keel, left lateral. D. Left pleopod 1 endopod, anterior. E. TS5–8, right dorsal. F. Left uropod, ventral. G. AS5–6, telson and left uropod, dorsal. Scale bar: A–B, E–G = 5 mm; C–D = 2.5 mm.