Neosarmatium australiense, Ragionieri & Fratini & Schubart, 2012

Ragionieri, Lapo, Fratini, Sara & Schubart, Christoph D., 2012, Revision Of The Neosarmatium Meinerti Species Complex (Decapoda: Brachyura: Sesarmidae), With Descriptions Of Three Pseudocryptic Indo-West Pacific Species, Raffles Bulletin of Zoology 60 (1), pp. 71-87 : 83

Neosarmatium australiense , new species

( Figs. 1d , 2d , 3d,h , 4d,h , 5d , 6g,h )

Neosarmatium meinerti: Robertson, 1986: 237 ; 1988: 235; Camilleri, 1989: 453; Robertson & Daniels, 1989: 191; Davie, 1982: 207 (in part); 1984: 262 (in part); 1994: 35 (in part); 2002 (in part); 2005: 152.

Material examined. — Holotype: male (39.85 × 34.77 mm) ( QM-W29085 ; former MZUF 3659 ), Darwin, Australia, coll. L. Ragionieri, 13 Aug.2006 . Paratypes: AUSTRALIA: 1 male (41.71 × 36.98 mm) ( MZUF 2968 ), Darwin , East Point, coll. L. Ragionieri, 13 Aug.2006 ; 1 male (39.27 × 29.07 mm) ( MZUF 2970 ), Darwin Mindil Beach , coll. L. Ragionieri, 13 Aug.2006 ; 4 males (36.50 × 31.39 mm; 35.68 × 30.15 mm; 24.93 × 20.95 mm; 22.18 × 18.65 mm) ( MZUF 2971 ), Darwin , Charles Darwin National Park, coll. L. Ragionieri, 13Aug.2006 ; 1 male (35.05 × 30.08 mm) ( MZUF 3658 ), Darwin , University of Darwin, coll. L. Ragionieri, 13 Aug.2006 ; 2 males (26.50 × 23.03 mm; 27.23 × 23.71 mm) ( MZUF 2969 ), Darwin , University of Darwin, coll. L. Ragionieri, 13 Aug.2006 ; 1 female yellow morph ( QM-W25080 ), NT: Kakadu N.P.: East Alligator Estuary , coll. P. Davie, Jun.1981 .

Diagnosis. — Carapace borders convexly rounded, with gentle cleft corresponding to second anterolateral tooth ( Fig. 2d ). Male chela characterised by presence of a single line of weak tubercles along inner palm surface ( Fig. 3h ), with palm height 1.78 (± 0.08; n = 10) times maximum chela width. Descending slope of palm (with parallel prominent ridge) at articulation with dactylus almost transverse ( Fig. 3d ). Lower margin of chela convex. Dorsal surface of dactylus covered with tubercles until tip ( Fig. 4d, h ). Male abdomen straight, relatively more quadrate; somite 6 with proximal width 1.14 (± 0.081; n = 10) times length; telson length 1.18 (± 0.07; n = 10) times width ( Fig. 5d ).

Remarks. — Northern Australia is the only area where the two colour morphs occur sympatrically. Notwithstanding the coexisting presence of the two colour morphs, the main diagnostic morphological characters of this species are consistent. Ragionieri et al. (2009) did not record any genetic differences between the two colour morphs.

Etymology. — Neosarmatium australiense , new species has been named according to its geographic distribution which is the western Australian coast, Kimberly coast, to northern Australia, till the Gulf of Carpentaria.

Habitat. — Neosarmatium australiense , new species lives in the rearward mangrove zone which receives water just during the spring tide ( Davie, 1994). Usually it is associated with well-developed forests of Avicennia marina , but it is not uncommon in Avicennia marina parkland.

Ecology. — Currently there is no information about the feeding behaviour or bioturbation activity of this species in Australia. However, there are some studies on Neosarmatium which suggest similar feeding behaviour and ecological function of Australian species compared to African ones ( Robertson, 1986; 1988; Camilleri, 1989; Robertson & Daniels, 1989).

Distribution. — North-western Australia from Gulf of Carpentaria to the Kimberly Coast.

Figures

Fig. 1. Frontal view of four species of Neosarmatium: a, N. africanum, new species, holotype male (42.83 × 38.33 mm) (MZUF 678), Somalia; b, N. meinerti (De Man, 1887) paratype male (40.26 × 35.60 mm) (MZUF 2931), Seychelles; c, N. asiaticum, new species, holotype male (38.52 × 33.11 mm) (NMNS-6327-001), Taiwan; d, N. australiense, new species, holotype male (39.85 × 34.77 mm) (QM- W29085), Australia.

Fig. 2. Dorsal view of carapaces of four species of Neosarmatium: a, N. africanum, new species, holotype male (42.83 × 38.33 mm) (MZUF 678), Somalia; b, N. meinerti (De Man, 1887), paratype male (40.26 × 35.60 mm) (MZUF 2931), Seychelles; c, N. asiaticum, new species, holotype male (38.52 × 33.11 mm) (NMNS-6327-001), Taiwan; d, N. australiense, new species, holotype male (39.85 × 34.77 mm) (QM-W29085), Australia.

Fig. 3. Outer and inner surfaces of the right chelae of four species of Neosarmatium: a, e, N. africanum, new species, holotype male (42.83 × 38.33) (MZUF 678), Somalia; b, f, N. meinerti (De Man, 1887), paratype male (40.26 × 35.60) (MZUF 2931), Seychelles; c, g, N. asiaticum, new species, holotype male (38.52 × 33.11 mm) (NMNS-6327-001), Taiwan; d, h, N. australiense, new species, holotype male (39.85 × 34.77 mm) (QM-W29085), University of Darwin, Darwin, Australia.

Fig. 4. Dorsal view of distal chelipeds and dactyli: a,e, Neosarmatium africanum, new species, holotype male (42.83 × 38.33 mm) (MZUF 678), Somalia; b,f, N. meinerti (De Man, 1887), paratype male (40.26 × 35.60 mm) (MZUF 2931), Seychelles; c, g, N. asiaticum, new species, holotype male (38.52 × 33.11 mm) (NMNS-6327-001), Taiwan; d, h, N. australiense, new species, holotype male (39.85 × 34.77 mm) (QM-W29085), Australia.

Fig. 5. Male abdomens: a, Neosarmatium africanum, new species, holotype male (42.83 × 38.33 mm) (MZUF 678), Somalia; b, N. meinerti (De Man, 1887), paratype male (40.26 × 35.60 mm) (MZUF 2931), Seychelles; c, N. asiaticum, new species, holotype male (38.52 × 33.11 mm) (NMNS-6327-001), Taiwan; d, N. australiense, new species, holotype male (39.85 ×34.77 mm) (QM-W29085), Australia.

Fig. 6. Male left first gonopods and corresponding distal parts: a, b, Neosarmatium africanum, new species, holotype male (42.83 × 38.33 mm) (MZUF 678), Somalia; c, d, N. meinerti (De Man, 1887), paratype male (40.26 × 35.60 mm) (MZUF 2931), Seychelles; e, f, N. asiaticum, new species, holotype male (38.52 × 33.11 mm) (NMNS-6327-001), Taiwan; g, h, N. australiense, new species, holotype male (39.85 × 34.77 mm) (QM-W29085), Australia.