Nasima dotilliformis Alcock 1900

Nasima dotilliformis (Alcock, 1900)

(Figs. 5, 6, 10 C)

Clistostoma (spelling incorrect) dotilliforme Alcock, 1900: 373.

Cleistostoma dotilliforme – Alcock & McArdle 1903: pl. 54 fig. I.

Paracleistostoma dotilliforme – Manning & Holthuis 1981: 201, 208 (no new material).

Cleistostoma dotilliforme – Serène 1968: 101 (in list). – Jones & Clayton 1983: 188, fig. 3. – Al-Khayat & Jones 1996: 806 (larvae).

Nasima dotilliformis – Manning 1991: 304, fig. 4 (no new material). – Al-Khayat & Jones 1996: 806, Fig. 6. – Ng et al. 2008: 233.

Material examined. PERSIAN GULF: 2 males (10.5 x 15.0 mm, other badly damaged), 2 females (5.3 x 7.5 mm [immature], 10.5 x 15.2 mm) (NHM 1964.3.2.1–2), Persian Gulf; 2 males (10.1 x 14.4 mm, 11.7 x 16.5 mm), 1 female (12.3 x 17.4 mm) (NHM 1974.389), station 1971.5/27/2, probably Persian Gulf, coll. J. Birchard, 1971. ABU-DHABI: 1 female (11.0 x 16.2 mm) (NHM 1963.10.24.9), Persian Gulf. BAHRAIN: 1 damaged female (NHM 1974.421), burrow in bank of channels among small mangroves, in creamy clay-mud, end of Kawari Bridge, Persian Gulf, coll. A. L. Rice, 1 June 1971. IRAQ: 11 males (4.9 x 6.9 mm –8.9 x 12.6 mm), 12 females (2.8 x 3.9 mm –10.0 x 14.1 mm) (ZRC 2009.843), 7 males, 5 females (MSC), Ras Al-Pisha, 29°55'40.01"N 48°36'37.29"E, Fao Region (Shatt Al-Arab), coll. M. D. Naser, 2009; 3 males (10.7 x 15.1 mm, 4.4 x 6.2 mm, 3.7 x 5.4 mm), 1 ovigerous female (8.1 x 11.4 mm) (ZRC 2009.834), Shatt Al-Basrah, 30°24'21.41"N 47°46'43.23"E, coll. M. D. Naser, 2009. KUWAIT: 1 male (7.5 x 10.6 mm) (NHM 1984.497), Sulaibikhat mudflat; 2 females (6.7 x 9.5 mm, 6.8 x 9.5 mm) (NHM 1984.496), Sulaibikhat mudflat, coll. D. Clayton; 1 male (7.0 x 9.9 mm), 4 females (largest 6.5 x 9.2 mm) (NHM 1981.500), mudflats. PAKISTAN: 3 males (6.1 x 8.9 mm, 6.4 x 9.9 mm, 8.0 x 11.5 mm) (USNM 205924), coll. R. B. Manning, 29 October 1984; 3 females (largest 11.4 x 16.9 mm) (with larvae) (NHM uncat.), Native Jetty, West Wharf, Karachi; 6 males (4.2–6.5 mm x 6.4–9.6 mm), 1 female (8.7 x 13.0 mm) (NHM 1984.410), mangroves of Mandra Island, coll. N. Ghani, 4 April 1982.

Type locality. Karachi, Pakistan.

Description. Carapace width to length ratio 1.39-1.55 (mean 1.44); dorsal surface with regions well demarcated, distinct, with 2 shallow transverse concavities just behind external orbital tooth, slightly taller granules immediately posterior to external orbital tooth forming lobe (sometimes low) along anterolateral margin; posterolateral margin beaded; small cluster of granules in center of branchial region; beaded submarginal ridge on posterior carapace margin. Suborbital ridge with row of granules, visible in frontal view. Front deflexed. Supraorbital margin weakly beaded, slightly sinuous along outer portion dorsally; infraorbital margin more strongly beaded, inner angle rounded, not distinctly separated from rest of infraorbital margin, granular ridge below infraorbital margin. Antennule with large basal segment filling entire antennular fossa. Epistome compressed, anterolateral angle acute, posterior margin thick, posteromedial tooth triangular with pointed apex. Anterolateral region sunken, posterolateral region raised in shelf-like manner, posterior margin weakly lobate on either side of posteromedial tooth, inter-antennular septum broad, with median ridge. Pterygostomian region with shallow, Y-shaped groove, lateral pterygostomian region with lateral concavity just below outer lateral edge of orbit.

Chelipeds relatively slender, not swollen or enlarged in both sexes or largest specimens; fingers of chela bearing dorsal, ventral rows of long setae, both ending in spoon-shaped tips, movable finger without molariform tooth or denticles; distal median portion of ventral edge of propodus lined by widely spaced granules. Female chelae less spatulate than in male.

Ambulatory legs (P2–P5) relatively robust, relatively broader in small males, females; anterior margins granular with distal edges sharper, anterior margins of carpi, propodi with thick tomentum; P3, P4 longest, P5 shortest; meri flattened laterally, appearing foliaceous; dorsoanterior margins of P3, P4 meri lined with proportionately more prominent granules, ventral margins lined with small sharp granules, appearing gently serrated; second, third ischia with tooth on posterior margin.

Surface of thoracic sternum relatively smooth; sternites 1–3 compressed, narrow, with sparse setae, sternites 1, 2 fused, anterior edge rounded, broad, groove separating sternites 1, 2 from 3, ends of groove do not reach anterolateral edge of sternum, outer ends of groove do not reach anterolateral margins of sternum; anterolateral angle of sternite 4 large, triangular, with oblique ridge running across, small weakly angular lobe on anterior to anterolateral angle, anterior edge of sternal concavity broad, squarish.

Male abdominal somite 1 slightly broader, wider than somite 2, not reaching P5 coxae, exposing part of thoracic sternite 8; somites 2-5 immobile; sutures between somites 2-4 shallow, barely discernible except for median, lateral parts, somites 4, 5 with distinct suture; somite 5, 6 with distinct suture but barely mobile; somites somites 5, 7 longer than others; telson with tip rounded, longest. Female abdomen subcircular, covering most of thoracic sternum; all somites free.

G1 recurved, with distal third more sharply bent; low lobe on submedian inner (sternal surface) of recurved part; subapical region of G1 moderately densely covered with backward-curving, robust spines, apex conical, with short, tapered tip.

Remarks. Alcock (1900) described Cleistostoma dotilliforme from a single ovigerous female (7.0 x 9.0 mm) from Karachi, Pakistan. Presumably, this specimen is still in the Indian Museum (present day Zoological Survey of India) but we were unable to obtain it for study. However, the specimens we have examined from and near Pakistan match Alcock's (1900) descriptions as well as Alcock & McArdle’s (1903) excellent figure well.

Manning (1991) examined additional specimens and subsequently transferred the species to a new genus, Nasima, and described the G1, for the first time, as "recurved, bulbous, spiny apex crossing shaft, lacking protruding appendages". He did not list the material examined, except to say that it was in the USNM collections. We have compared specimens of N. dotilliformis from USNM and NHM and found the material to be conspecific.

Jones & Clayton (1983: 188) noted that the indentation behind the external orbital tooth is obscure in larger specimens but this is not always true. In general, the strength and shape of the anterolateral lobe in N. dotilliformis varies with the size of the specimen. The ovigerous female holotype measured only 7.0 x 9.0 mm and had only a very small lobe, hardly visible in Alcock & McArdle’s (1903) figure. The lobe is usually more prominent in larger specimens, (Fig. 5). This is obvious in the large series from Iraq, with the largest males and females having the most distinctly developed lobe (Fig. 5 C). In the largest male (11.7 x 16.5 mm, NHM 1974.389) from the Persian Gulf, however, the lobe is relatively lower (Fig. 5 B). The small cluster of granules in the center of the branchial region may not be distinct in smaller females. The region where the cluster of granules is located is swollen in large specimens of both sexes. As in Leptochryseus kuwaitense, the ambulatory legs of females (especially the P3 and P4 meri) are relatively shorter and broader (Fig. 5 C).

Stephensen's (1946: 194) record of Cleistostoma dotilliforme from the Iranian Gulf is here considered indeterminate as he provides neither figure nor diagnosis of his single female specimen.

Habitat and Biology. Some of the present specimens from Iraq were found some distance inland, with the Shatt Al-Basrah site almost 200 km from the coastline. The substrates in both sites were soft silty clay. Despite the inland locations of Ras Al-Pisha and Shatt Al-Basrah, the salinity of the waters in both sites is close to that of seawater, averaging 32‰. This is due to the strong tidal influence and the presently limited flow of fresh water from the major rivers flowing down, the Karun River (from Iran) and Euphrates and Tigris (from Turkey) because of many projects upstream. In Iraq, however N. dotilliformis and M. arabicum live together in Ras Al-Pisha. See Jones & Clayton (1983) for a detailed account.

Geographical distribution. Saudi Arabia, Abu Dhabi and Trucial Coast (Arabian Gulf), Kuwait, Iraq (present record) and Pakistan.