Coleusia janani Giraldes, Al-Maslamani & Smyth, 2017, sp. nov.
Creators: name: Giraldes, Bruno Welter
name: Al-Maslamani, Ibrahim
name: Smyth, David
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Leucosiidae
Coleusia
Coleusia janani

description: Coleusia janani sp. nov.
(Figs. 1 ¯3)
Type material. Qatar. Holotype. male (cl 13.6 mm), ESCMC 0 0 161, 22 m, near offshore oyster bed in Qatar Marine Zone within the Arabian Gulf, 25o45’0.612”N 51o52’24.599”E, grab survey, 12.xi.14. Paratypes. female juvenile (cl 9.5 mm), ESCMC 0 0 162, 22 m, near offshore oyster bed in Qatar Marine Zone within the Arabian Gulf, 25o45’0.612”N 51o52’24.599”E, grab survey, 12.xi.14; female (cl 13.1 mm), ESCMC 0 0 163, 27 m, offshore soft substrate peripheral to oyster bed in Qatar Marine Zone within the Arabian Gulf, 25o 33’ 31.32”N 52o01’0.48”E, grab survey, 11.xi.14; female (cl 12.8 mm), OUMNH.ZC.2016-01-112, same data; male (cl 14.2 mm [broken triangular rostrum and lacking red circles]), OUMNH.ZC.2016-01-113, 26m, offshore soft substrate peripheral to oyster bed in Qatar Marine Zone within the Arabian Gulf, 26o01’50.988”N 51o46’9.012”E, trawl survey, 13.xi.14.
Description. Holotype. Carapace globose to rhomboidal, (Figs. 1, 2 A) 1.19 times longer than wide; dorsal surface shiny, smooth, closely punctate only in anterior central area; posteriorly slightly punctate. Large, concave margin in hepatic region, about 0.6 times as large as maximum carapace width. Antero-lateral border sharply crenulated (Figs. 2 A, G). Lateral margin of carapace with sequential granules, minutes anteriorly, increasing in size medially above the thoracic sinus, ending above third pereiopod (Figs. 2 A, D). Posterobasal margin laterally expanded, forming small wings responsible for square shape of posterior carapace (Figs. 1, 2 H); line of granules extending to basolateral margin in line with the granules at thoracic sinus, overlapped with anterolateral line of granules between chelipeds, third walking pereiopod (Fig. 2 D). Pterygostomial region smooth (Figs. 2 A, D). Thoracic sinus plain, pterygostomial invagination with shallow, subtle Y-shaped cavity; with 4 perliform granules above cheliped basis (Figs. 2 A, B, D).
Frontal region of carapace produced upward, up-curved, forming central longitudinal, triangular elevation; concave dorsolaterally (Figs. 2 A, G). Frontal margin medially unidentate, small triangular rostrum with anterior margin rounded (Fig. 1). Antennular fossa and orbit in line at the upward margin; antennular fossa sealed by short antennae (Fig. 2 G). Orbit small, with a dorsolateral spine in the outer orbital margin, up the small fossa. Eyes retractable, small eyestalk. Width of upward frontal region (between orbits) about 0.21 times shorter than total carapace width. External maxillipeds flat, concealing trapezoid buccal opening; endopod with long triangular merus, passing ventral edge of antennular cavity in frontal margin of carapace (Fig. 1 G); merus 1.27 times longer than ischium. Exopod of external maxillipeds with merus 1.6 times longer than ischium.
Thoracic sternites, abdomen punctate. Abdomen, smooth with narrow somites 1, 2; somites 3–6 fused with 2 convex (Fig. 2 F), rounded protuberances proximally (Fig. 2 H); somite 6 separated from proximal segments by suture, dorsally smooth with subparallel lateral margins converging distally only near the 4/5 of its length; telson triangular, slightly elongated, 1.1 times longer than wide (Fig. 2 F). Abdominal cavity nearly reaching buccal cavity (Figs. 2 F, G). Male first pleopod (G1) with shaft coiled three times on its axis; with apical process pointed, straight, upward, not curved (Figs. 2 A, C, E).
Chelipeds with merus, carpus, chela punctate. Cheliped merus trigonal; 0.6 times as long as carapace; anterior, posterior margins lined with perliform granules that slightly diminishing in size distally in approximately 5/6 of its length; upper surface with 6 small granules grouped proximally, followed by 2 large perliform granules, distal 3/4 smooth (Figs. 1, 2 A); lower surface, with anterior margin dense granulated proximally, decreasing distally, smooth posteriorly (Fig. 2 F). Carpus smooth, without granules (Figs. 1, 2 A). Palm elongated; propodus 1.3 times longer than wide, its upper margin rounded, lower margin with row of small granules; dactyls almost as long as propodi (Figs. 1, 2 A, F). Walking pereiopods unequal in size, decreasing from second to fifth (Figs. 1, 2 A, F). Larger second pereiopod reach the cheliped carpus, 0.8 times length of carapace. Pereiopodal meri with margin lined with minute granules along upper margin. Pereiopodal carpi rounded, smooth; propodi dorsally, ventrally carinate.
Female paratypes (Figs. I-L): Shorter front 0.19 times width of carapace. Third maxilliped (Fig. 2 J) setose along endopod, margin of exopod merus; keel-like ischium of endopod, longitudinal convex (not flattened) elevation. Chelipeds proportionally short (Fig. 2 I), with merus 0.47 times the length of carapace, shorter propodi. Pereiopods shorter than male pereiopods, with longer second pereiopod 0.7 times length of carapace. Abdomen with somites 3¯6 fused, greatly enlarged; thick, convex, shield-like shape covering entire thorax; suture separating segment 6 absent; segment 1, 2, telson free (Fig. 2 I). Abdominal cavity reaching buccal cavity with telson overlapping part of endopod of third maxilliped (Figs. 2 I, J, K). Gonopore (vagina) semicircular, in sternite 5; strong inner edge, rounded and with deeper groove; outer edge more straight with longitudinal fissure (Figs. 2 K, L).
Colour in life (Fig. 1). Carapace with bright orange/greyish background. Pair of large ocelli on the gastric region on each side of the carapace; with small white centres and lined by thin red outer rings overlapped with an inclined 8-shape. Intestinal region with reddish blotches on either side and without lined margins. Carapace with three bright orange markings, two anterolateral and one posterolateral, on lateral margins. Chelipeds and walking pereiopods with orange transversal bands. Meri of chelipeds with white granules and large proximal orange band covering 4/5 of its length; orange articulations in the carpi; propodus with light orange band proximally; dactyls with white tips and bright red band on the proximal region. Walking pereiopod white with one bright orange band per segment.
Type locality. Arabian Gulf; off Qatar.
Etymology. In recognition of the Qatar University Oceanographic RV Janan used in the collection of the present material.
Distribution. Currently only known from the type locality.
Ecology. Offshore zones with sandy mixed substrates of gravel and mud; depth between 22 and 27 m. Material collected with water temperature that varied between 27 and 28o C and salinity between 39 and 41 ppt.
Remarks. The present study increases to seven the number of species within the genus Coleusia (Galil 2006; Ng et al. 2008, 2014; Promdam et al. 2014). Coleusia janani n. sp. differs from all other species in the genus in the apical shape of the male G1 (Figs. 1 F, 2E), which is pointed, straight, and not curved (Galil 2006; Ng et al. 2014; Promdam et al. 2014). Coleusia janani n. sp. is otherwise similar to C. biannulata in some features, such as the thoracic sinus with a row of four perliform granules, and in the colour pattern, with a pair of large orange ocelli on the gastric region, with very broad red outer rings. Coleusia janani n. sp., however, differs from C. biannulata in the straight upward apical shape of the G1, being twisted and curved outwards in the latter; the palm of C. janani being less elongated (1.3 times as long as wide in contrast to 1.4 in C. biannulata); the carapace being only densely punctate in proximal regions of C. janani n. sp. and only being sparsely punctate in C. biannulata; and in thin six reddish spots, which are more anteriorly positioned than in C. biannulata.
The physicochemical and biological parameters in the waters of the eastern coast of the Arabian Gulf are similar to those found in the Gulf of Oman and the Pakistani coast where C. biannulata occurs (Fig. 3). There are nevertheless considerable differences in the waters of the western Arabian coast (Bosch et al. 2008; Riegl & Purkis 2012; Al-Ansari et al. 2015; Al-Maslamani et al. 2015). It is quite possible that C. biannulata and C. janani cooccur in some regions of the Arabian Gulf where environmental conditions overlap. Conversely the dissimilarities in temperature and salinities between the east and west coast are certainly extreme enough to create a biogeographic barrier could be isolating the populations and thereby maintaining vicariance. For this reason, we do not dismiss the presence of C. biannulata in the Arabian Gulf as reported by Alcock (1896, as Leucosia longifrons var neocaledonica A. Mine Edwards, 1874).
description: Published as part of Giraldes, Bruno Welter, Al-Maslamani, Ibrahim & Smyth, David, 2017, A new species of leucosiid crab (Decapoda: Brachyura: Leucosiidae) from the Arabian Gulf, pp. 389-395 in Zootaxa 4250 (4) on pages 390-393, DOI: 10.11646/zootaxa.4250.4.9, http://zenodo.org/record/495328