Macrophthalmus sulcatus H. Milne-Edwards, 1852

Naderloo, Reza, Türkay, Michael & Apel, Michael, 2011, Brachyuran crabs of the family Macrophthalmidae Dana, 1851 (Decapoda: Brachyura: Macrophthalmidae) of the Persian Gulf, Zootaxa 2911, pp. 1-42 : 33-37

Macrophthalmus sulcatus H. Milne-Edwards, 1852

( Figs. 19 a–e, 20a–f, 21c–d)

Macrophthalmus sulcatus H. Milne-Edwards 1852: 156 . — Alcock 1900: 379.

Macrophthalmus (Macrophthalmus) dilatatus sulcatus — Barnes 1970: 216, fig. 4. — Titgen 1982: 149, 253 (in list). — Tirmizi & Ghani 1996: 112, fig. 42.

Macrophthalmus (Macrophthalmus) sulcatus — Pretzmann 1971: 482. — Apel & Türkay 1999: 134. — Apel 2001: 110.

Macrophthalmus sulcatus sulcatus — Pretzmann 1974: 438, figs. 2, –3. — Barnes 2010: 35 (in key), 40.

Macrophthalmus grandidieri — Basson et al. 1977: 60, 63, 228, 231, 235. — Titgen 1982: 253 (in list). — Clayton 1986: 87, fig. 3. — Jones 1986a: 159, pl. 45. — Vousden 1987: 35. — Tirmizi & Ghani 1996: 114, fig. 43. — Al-Khayat & Jones 1999: 58, 61.

Macrophthalmus dilatatus sulcatus — Al-Ghais & Cooper 1996: 417, fig. 6.

Type locality. Île de France (= Mauritius)

Material examined. Persian Gulf: Iran: 4 females (1 ovig.) ( SMF 36899), Bushehr city, coast of the Jofre police station, 28º 58'N, 50º 49'E, sandy band behind rocky/coral bed, 24.05.2008, R. Naderloo, A. Kazemi & H. Salehi; 1 male, 3 females ( SMF 36900), Bandar-Abbas, E. of city, 27º 11'N, 56º 21'E, muddy sand, 23.04.2008, R. Naderloo, A. Kazemi & A. Keykhosravi; 1 male ( SMF 36901), Qeshm I., 2 km E. of desalination centre, 26º 56'N, 55º 47'E, muddy sand with shells, 15.01.2008, R. Naderloo & M. Türkay; 2 males, 4 females (1 ovig.), 3 juv. ( SMF 36903), Bushehr, Laylateyn, sandy coast of khor (water channel), 17.10.2009, R. Naderloo & A. Kazemi; 1 male ( SMF 36885), Bushehr, Bandar-Rig, 29º 28'N, 50º 37'E, muddy sand flat, R. Naderloo & A. Kazemi; 1 male ( SMF 36902), Bushehr, Bavirat Police station, 30º 10'N, 50º 05'E, sandy substrate, (water channel), 17.10.2009, R. Naderloo & A. Kazemi.

UAE: 4 males ( SMF 36081), Ras al Khaymah, Mangrove, N. of Rams, 25º 53'N, 55º 02'E, sandy mud, 10.07. 1995.

Saudi Arabia: 5 males ( SMF 36088), Jubail Marine Wildlife Sanctuary, S. Dauhat al Dafi, 27º 8.23'N, 49º 23.41'E, sandy, 27.09.1992, M. Apel; 2 males, 2 females ( SMF 36084), N. Jubail, Abu Ali, 26.06.1992, M. Apel; 5 males, 6 females ( SMF 36090), Jubail Marine Wildlife Sanctuary, N. of Jubail, SW bank of Dauhat al Musallamiya, 27º 23.33'N, 49º 10.15'E, 22.06.1992, M. Apel; 1 male ( SMF 36097), Ras al Mishab, 28º 11.35'N, 47º 37.06'E, 28.01.1993; 1 female (ovig.) ( SMF 36090), Manifa Bay, 27º 34.1'N, 49º 10.15'E, 22.06.1992, M. Apel.

Comparative material. Malaysia: 1 male (NHM 1900:12:1:23), Santubong, Western Malaysia, coll. Shelford, det. R.S.K. Barnes; 1 male (NHM 1880:6), det. R.S.K. Barnes; 1 female ( MNHN B. 10968, CL = 7.3, CB = 16.5) Île de France ( Mauritius).

Redescription. Carapace ( Figs. 19 a, 21c) much wider than long (CB/CL = 2.3), relatively convex, bearing small granules on carapace; two rows of relatively large granules on epibranchial region ( Fig. 19 a), anterior one transverse, posterior one longitudinal; transverse line of small granules on posterior region, extending parallel to posterior margin, granules extensively lined. Regions well defined; furrows defining gastric, epibranchial regions remarkably deep. Frontal region smooth, deflexed; front narrow, about 0.12 times as wide as carapace; anterior edge smooth, slightly concave, nearly bi-lobed, frontal furrow faint, posteriorly divided.

Lateral margin ( Fig. 19 a) with three distinct teeth (including exorbital angle); first one remarkably smaller than second, elongatedly triangular, directed outwards; second one largest, broadly triangular, directed forwards, anterior, posterior margin sometimes slightly concave, separated from former by deep U-shaped notch; third one smallest, directed forwards; posterolateral margin nearly straight, very slightly converging posteriorly, with granules nearly high, long-spaced, beset with long setae.

Eyestalks narrow ( Fig. 19 a), long, with half of cornea extending beyond second lateral tooth; upper orbital margin convex, regularly granular,, granules small, with even smaller ones in between; lower margin granular, granules small, different-size, some relatively high, usually directed inwards.

Third maxilliped large, ischium slightly less than twice length of merus, inner margin of ischium, merus with long setae, outer margin without setae, outer surface smooth.

Chelipeds ( Fig. 19 d, e, 21c, d) nearly equal. Merus ( Figs. 19 b, c) with long setae along inner upper margin, becoming denser distally, 4–5 long spine-shaped tubercles on two thirds of distal margin; inner lower margin finely granular, 2–3 long spine-shaped ones subdistally; posterior margin with small granules. Carpus ( Fig. 19 e) with large spine-shaped tooth medially on upper inner margin, large spine-shaped tooth on inner proximal margin, some small ones between these two spines; outer surface finely granular in lower portion. Palm ( Figs. 19 d, e) long, about 2.3 times as long as high as in proximal part, gently becoming higher distally, outer surface ( Fig. 19 d) nearly smooth, covered with microscopic granules, dense granules on lower, upper margin; longitudinal ridge on lower portion, running from proximal part to near base of immovable finger, not reaching to latter, granular with large granules in middle part; inner surface ( Fig. 19 e) with patch of dense setae on upper portion of palm, inner surface of fingers, some long setae in between, large spine-shaped tooth on proximal portion, small granules on middle portion, lower proximal portion densely covered with small granules, distal lower portion depressed; upper margin with row of tubercles, large, conical, decreasing in size distally. Movable finger long, relatively narrow, curved inward distally, upper margin with small granules, cutting edge with small teeth, becoming larger large in proximal half. Immovable finger short, with median large tooth granular, markedly sinuous proximally, row of 7–8 denticles on distal portion.

Cheliped of females small, bearing long setae on posterior, lower inner margin of merus, margins of carpus; palm with upper margin being finely granular, lower margin faintly granular; lower half of outer surface depressed, upper half finely granular; inner upper margin of manus, fingers with long setae; cutting edges with numerous small teeth.

Walking legs narrow, long. Merus with small subdistal tooth, posterior margin minutely denticulate, that of third leg about 4.2 times as long as wide; propodus as long as dactylus; last leg very small, unarmed, with long setae on posterior, anterior margins of all segments.

Male abdomen ( Fig. 20 e) broadly triangular, segments 3, 4, 5 of same length; segment 6 slightly longer than previous ones; telson longer than segment 6, with margin curving, resulting in semicircular form.

Posteromedian margin of epistome strongly convex, faint ridge on anterior part of buccal cavity.

Male G1 moderately long ( Fig. 20 a), curved outward proximally; apical chitinous process ( Fig. 20 b) short, curved laterally, lateral surface depressed, apical margin nearly straight, distal opening ( Fig. 20 c) on mesiodorsal face; long setae around apical part, long plumose setae set sparsely along lateral, ventral surface.

Female gonopore ( Fig. 20 f) with margins moderately high at anterior, lateral sides; operculum large at inner side, nearly round, directed outwards.

Remarks. There are several records of this species from the Persian Gulf: Pretzmann (1971) recorded it from Bandar-Abbas ( Iran), Al-Ghais & Cooper (1996) from Umm al Qaiwain ( UAE), and Apel (2001) from Ras al Khaimah ( UAE) and Saudi Arabia. Furthermore, Apel and Türkay (1999) mentioned material identified as M. grandidieri recorded from the Persian Gulf [ Basson et al. (1977) from Saudi Arabia; Clayton (1986) and Jones (1986) from Kuwait; Vousden (1987) from Bahrain] that convincingly can be assigned to M. sulcatus . Therefore, M. grandidieri has neither been recorded from the Arabian side of the Persian Gulf nor was it found in the present study along the Iranian coast. Macrophthalmus sulcatus , however, is a quite common species of the intertidal zone of sandy shores throughout the Persian Gulf. We also re-examined some material from the eastern Indian Ocean that revealed all specimens of the Persian Gulf are identical with those from the eastern limit of the distributional range. A female specimen in the dry collection of MNHN lacking most of the appendages (MNHN 10968), which is labelled “Ile France ” (= Mauritius), and was indicated by Apel (2001) as the type material, even though there is no label indicating its type status. Because this specimen is the only record from Mauritius or adjacent regions, there is still some doubt regarding the correct labelling. Persian Gulf specimens, however, are very similar to this specimen, in particular in carapace characters.

Barnes (1970) defined two subspecies, M. dilatatus dilatatus and M. dilatatus sulcatus , and synonymised M. malaccensis Tweedie, 1937 , with the latter. Ng et al. (2008) listed M. malaccensis and M. sulcatus as two distinct species. Barnes (2010) attributed M. sulcatus sulcatus and M. sulcatus malaccensis as subspecies and mentioned that M. sulcatus sulcatus is confined to the Persian Gulf and Arabian Sea, whereas the latter inhabits muddy sand flats in the Bay of Bengal and western Malaysia. We follow Ng et al. (2008) in considering M. sulcatus as a distinct species, and propose that M. sulcatus is not limited to the western Indian Ocean, as we examined material from western Malaysia, which is surely identical with those from the Persian Gulf (NHM 1900:12:1:23). Barnes’s (1970) illustrations and description of M. sulcatus was based on material from western Malaysia (Santubong). The taxonomic problem of these two species needs to be further clarified and their geographical distribution needs to be studied using material from different regions.

Biology. Macrophthalmus sulcatus inhabits the mid intertidal zone, where it is found on shores with fine sand, sometimes mixed with mud and shells. It is a medium-size species (largest male CL = 13.70, CB = 29.86 mm, largest female CL = 12.61, Cb = 28.90 mm). Nothing is known about its life history.

Geographical distribution. Indian Ocean: Mauritius (?), Persian Gulf, Pakistan, west coast of India, western Malaysia.

Figures

FIGURE 19. Macrophthalmus sulcatus H. Milne-Edwards, 1852, male (SMF 36901): a, posterior surface of carapace, left side; b, merus of male cheliped, inner surface; c, merus of male cheliped, lower surface; d, cheliped of male, outer surface; e, cheliped of male, inner surface of carpus and manus.

FIGURE 20. Macrophthalmus sulcatus H. Milne-Edwards, 1852: a – c, e, male (SMF 36901); d, f, female (SMF 36899). a, G 1 of male, ventral surface (right); b, apical part of G 1, ventral surface; c, apical part of G 1, dorsal surface; d, female abdomen, penultimate segment and telson; e, male abdomen; f, female gonopore, right.