Anamathia rissoana (Roux, 1828)

Lee, Bee Yan, Richer De Forges, Bertrand & Ng, Peter K. L., 2020, Revision of the deep-water spider crab genus, Scyramathia A. Milne-Edwards, 1880, with the description of a new species from the Mediterranean and notes on Rochinia A. Milne-Edwards, 1875, and Anamathia Smith, 1885 (Crustacea, Decapoda, Brachyura, Epialtidae), Zoosystematics and Evolution 96 (2), pp. 537-569 : 537

publication ID	https://dx.doi.org/10.3897/zse.96.48041
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scientific name	Anamathia rissoana (Roux, 1828)
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Treatment

Anamathia rissoana (Roux, 1828) Figs 16A-C View Figure 16 , 17A-C View Figure 17 , 18A-F View Figure 18

Amathia rissoana Roux, 1828: 2 unnumbered paes, pl. 3 (type locality: Mediterranean).

Amathia Rissoana : H. Milne Edwards 1834 a: 286; H. Milne Edwards 1840: pl. 34 bis fig. 2; Heller 1863: 29, 30, pl. 1 figs 4, 5.

Anamathia rissoana : Smith 1885: 493 (list); A. Milne-Edwards and Bouvier 1899: 43, 44, pl. 1 fig. 5; A. Milne-Edwards and Bouvier 1900: 138, pl. 20 fig. 11; Pesta 1918: 348, fig. 112; Bouvier 1922: 80; Rathbun 1925: 204 (list); Bouvier 1940: 345-347, fig. 210, pl. 14 fig. 4; Kramp 1947: 3, fig. 1; Dieuzeide 1950: 52; Dieuzeide 1955: 20 (list), 57, fig. 10; Holthuis 1962: 242 (list); Vervoort 1966: 383, fig. 6; Zariquiey Álvarez 1968: 465, figs 7c, 153b, 154g, h; Holthuis 1977: 74; Manning and Holthuis 1981: 253 (list), 254; Relini et al. 1986: 145 (table); Guerao and Abelló 1996: 245-250, Figs 1 View Figure 1 - 3 View Figure 3 ; Mura et al. 2005: 110-115, figs 1-8; Ng et al. 2008: 102 (list); Maynou and Cartes 2012: table 1; Araújo et al. 2014: 38 (list); Bo et al. 2015: 14, fig. 4P; Mastrototaro et al. 2016: 244-246, fig. 2A-H; Mastrototaro et al. 2017: 214, 216 (list), 217, 222, figs 5j, k, 6j-n, table 3; Taviani et al. 2017: 65, fig. 6B, table 3; Ceccon and De Angeli 2018: 151, fig. 2.1; Tavares and Santana 2018: 208 (list), figs 3, 12B, 13C, D.

Rochinia rissoana : Garth 1958: 283, 289; Clark 1986: 192, 193 (map); d’Udekem d’Acoz 1999: 194; González-Gordillo et al. 2001: 280 (list); Mura and Corda 2011: 679 (table).

Rochinia (Anamathia) rissoana : Cartes et al. 2013: 62.

Material examined.

North Atlantic Ocean • 1 ♂ (22.9 × 16.1 mm), 1 ♀ (23.5 × 16.5 mm) ( SMF 4420), stn 9C-189, 30°5.1'N, 28°38.4'W, 340-305 m, coll. Meteor Expedition, 26 July 1967; 4 ♂♂ (26.2 × 17.5 mm, 24.0 × 15.2 mm, 19.9 × 12.8 mm, 13.1 × 8.2 mm), 4 ovigerous ♀♀ (27.5 × 17.2 mm, 25.1 × 16.2 mm, 23.1 × 14.6 mm, 21.0 × 13.4 mm, 19.8 × 12.5 mm), ( SMF 4410), stn 9c-130, 36°41.1'N, 14°14.8'W, 216-225 m, coll. Meteor Expedition, 3 July 1967; 1 ♂ (16.5 × 11.2 mm), 1 ♀ (24.0 × 15.4 mm), 2 juveniles ( SMF 5542), stn 19-131, 30°8'N, 28°38.5'W, 269 m, coll. Meteor Expedition, 17 February 1970.

Description.

Carapace pyriform, covered with layer of setae, smooth when denuded (Figs 16A View Figure 16 , 17A View Figure 17 ). Supraorbital eave fused with carapace with blunt preorbital angle; postorbital lobe cup-like, small (Fig. 17B View Figure 17 ).

Carapace with 13 spines: 1 hepatic spine, 1 protogastric spine, 1 metagastric spine, 1 lateral epibranchial spine, 1 lateral branchial spine, 1 cardiac spine, 1 metabranchial spine, 1 strong intestinal spine near posterior of carapace (Figs 16A View Figure 16 , 17A View Figure 17 ).

Antennal flagellum shorter than pseudorostral spines. Basal antennal article longer than broad, narrow; straight outer margin with blunt distal angle. Presence of granule at base of article. Buccal frame covered by third maxilliped, distal angle of buccal frame distinct, highly protruded, forming blunt angle. Pterygostomial region with 2 or 3 granules on outer margin; second granule biggest (Fig. 17B View Figure 17 ).

Chelipeds slender, palm longer than dactylus; carpus with 2 spines on distal edge; merus with sharp spine on distal angle. Ambulatory legs slender; distal angle of merus blunt; P2 longest (Figs 16A View Figure 16 , 17A View Figure 17 ).

Male thoracic sternum slightly concave, constricted between sternites 1, 2 and 3, 4; sternites 3, 4 widest (Fig. 17B View Figure 17 ). Male pleon with semi circular telson and 6 somites; somites 2, 3 widest; large granule on middle of second to fifth somites (Fig. 16B View Figure 16 , 17B View Figure 17 ). Adult female with round pleon, with all somites free (Fig. 16C View Figure 16 ). G1 straight, with flattened, sharp tip (Fig. 18A-D View Figure 18 ).

Remarks.

Roux (1828) described Amathia rissoana from the Mediterranean, and it was noted by Roux (1828) that the rare crab is found 20 metres deep amongst "les algues et les focus". Roux (1828) did not indicate the number of specimens that was examined, but he had at least one male and one female which were figured ( Roux 1828: pl. 3; reproduced here as Fig. 16A-C View Figure 16 ). These specimens are therefore syntypes; but the whereabouts of Roux’s specimens are not known. His figures, however, are relatively detailed and leave no doubt regarding the species identity.

The morphology of this species is distinct from species of Rochinia in having distinct carapace spines (Figs 16A View Figure 16 , 17A View Figure 17 ) (versus smooth carapace in Rochinia ; Fig. 1A View Figure 1 ), and buccal frame with highly protruded blunt angle (Fig. 17B View Figure 17 ) (versus lack of protruded angle on buccal frame in Rochinia ; Fig. 1B View Figure 1 ).

There are studies that report the prezoea and first zoea stage morphology for A. rissoana ( Guerao and Abelló 1996), as well as the size of the species at sexual maturity ( Mura et al. 2005). This species has been noted to be associated with bamboo coral, Isidella elongata (Esper, 1788) (see Maynou and Cartes 2012; Cartes et al. 2013; Mastrototaro et al. 2017), and black coral, L. glaberrima (see Bo et al. 2015), and typically with the hydroid epibiont, Rosalinda incrustans (Kramp, 1947), on its carapace ( Kramp 1947; Vervoort 1966; Mastrototaro et al. 2016). This species was also recently observed to have R. incrustans on its pseudorostral spines and climbing on colonies of I. elongata to catch small prey ( Mastrototaro et al. 2017: 217, figs 5j, k, 6j-n).

A new fossil species, Lessiniamathia bolcense Ceccon & De Angeli, 2018, was recently described (see Ceccon and De Angeli 2018).

Distribution.

Madère (= Madeira), Açores (= Azores), Méditerranée (= Mediterranean) ( Bouvier 1922), NE Atlantic, SE Atlantic (Azores, Madeira), Mediterranean Spain, Baleares Islands, Italy, and Adriatic ( Clark 1986).