Raoulia galea, Ng & Rahayu, 2014

Ng, Peter K. L. & Rahayu, Dwi Listyo, 2014, Revision of the family Acidopsidae Števčić, 2005, and the systematic position of Typhlocarcinodes Alcock, 1900, Caecopilumnus Borradaile, 1902, and Raoulia Ng, 1987, with descriptions of two new genera and five new species (Crustacea: Brachyura: Goneplacoidea), Zootaxa 3773 (1), pp. 1-63 : 31

Raoulia galea sp. nov.

( Figs. 5E , 18 , 19F–L )

Material examined. Holotype: male (9.4 × 7.4 mm) ( ZRC 2000.0980 ), intertidal mud flats, Phuket, Thailand, coll. P.K.L. Ng, 3–6 May 2000.

Diagnosis. Carapace width 1.3 times length ( Fig. 18A ). Junction between frontal, supraorbital margins appears gently curved in frontal view ( Fig. 18C ). Third maxilliped merus shorter than ischium; ischium quadrangular, 1.1 times as long as broad ( Figs. 5E , 19G ). Ambulatory legs short; merus of last ambulatory leg 2.8 times as long as broad ( Fig. 18A ). G1 with distal half distinctly curving towards abdomen in situ, distal part gradually tapering ( Fig. 19H–K ).

Colour. The freshly collected specimen has a dirty white carapace and pereopods, with the setae brown.

Etymology. The name is derived from Latin galea for helmet, alluding to the general shape of the carapace of the species. The name is used as a noun in apposition.

Remarks. Raoulia galea sp. nov. is most similar to R. limosa , but it can be separated by possessing a somewhat a more quadrate carapace ( Fig. 18 ; Figs. 13A , 14A , 15A for R. limosa ); the junction between the frontal and supraorbital margins of R. galea is gently curved (in frontal view) ( Fig. 18C ) (at right angles in R. limosa ; Fig. 13D , 14C ); the merus of the third maxilliped is more subovate, with the anterolateral margin gently convex ( Figs. 5E , 19G ) (more rounded, with the anterolateral margin markedly convex in R. limosa ; Figs. 5C , 16B ). The G1s of the two species are superficially similar, but in R. galea sp. nov., the distal half curves towards the abdomen (i.e. directed ventrally) in situ ( Fig. 19H–K ), while in R. limosa , it is bent outwards ( Fig. 16D–G ). This argues against the two species being conspecific.

Although R. galea sp. nov. is also found in the Indian Ocean like R. piroculata , its carapace appears more rounded in general appearance ( Fig. 18A ; Fig. 17A for R. piroculata ).

Distribution. Phuket, Andaman Sea coast of Thailand, eastern Indian Ocean; intertidal.

Figures

FIGURE 5. Right third maxillipeds. A, Acidops cessacii (A. Milne-Edwards, 1878), syntype female (14.1 × 10.0 mm) (NHM 99.3.23.66) Cape Verde (laterally inverted); B, Parapilumnus cristimanus (A. Milne-Edwards, 1873), male (16.3 × 12.5 mm) (ZRC 2003.90), Nansha Is. (Spratly Is.), South China Sea (laterally inverted); C, Raoulia limosa Ng, 1987, holotype male (8.3 × 6.3 mm) (ZMUC M58), off Marongas, Jolo, Philippines; D, Raoulia piroculata (Rathbun, 1911), lectotype female (7.3 × 5.5 mm) (USNM 41359a), Amirante Is., Indian Ocean; E, Raoulia galea sp. nov., holotype male (9.4 × 7.4 mm) (ZRC 2000.0980), Phuket, Thailand; F, Raoulia fortis sp. nov., holotype male (12.0 × 9.2 mm) (MNHN), Santo, Vanuatu (laterally inverted); G, Raoulia calva sp. nov., holotype male (6.6 × 5.2 mm) (ZRC 2013.1721), Society Is., French Polynesia; H, Caecopilumnus hirsutus (Borradaile, 1902), male (7.1 × 5.6 mm) (ZMA 261027), Flores, Indonesia (laterally inverted); I, Caecopilumnus crassipes (Tesch, 1918), male (11.8 × 10.1 mm) (ZRC 2013.1710) Lombok, Indonesia; J, Caecopilumnus loculatus sp. nov., holotype male (8.0 × 6.7 mm) (ZRC 2013.1723), Moorea, French Polynesia (laterally inverted); K, Thecaplax capillosa gen. et. sp. nov., holotype male (11.6 × 9.5 mm) (MZB), Lombok, Indonesia; L, Typhlocarcinodes integrifrons (Miers, 1881), lectotype male (8.5 × 6.9 mm) (NHM 81.24a), Goree I., Senegal.

FIGURE 13. Raoulia limosa Ng, 1987, holotype male (8.3 × 6.3 mm) (ZMUC M58), Jolo, Philippines. A, dorsal view; B, male abdomen; C, anterior thoracic sternum and sterno-abdominal cavity; D, frontal view of carapace; E, posterior thoracic sternum; F, outer view of right chela; G, outer view of left chela.

FIGURE 14. Raoulia limosa Ng, 1987, male (8.3 × 6.5 mm) (ZRC 2013.1703), Lombok, Indonesia. A, dorsal view; B, anterior thoracic sternum and sterno-abdominal cavity; C, frontal view of carapace; D, posterior thoracic sternum; E, outer view of right chela; F, outer view of left chela.

FIGURE 15. Raoulia limosa Ng, 1987, male (4.8 × 3.5 mm) (ZMA 240126), Talaut Is., Philippines. A, dorsal view; B, anterior thoracic sternum and sterno-abdominal cavity.

FIGURE 16. Raoulia limosa Ng, 1987. A–H, holotype male (8.3 × 6.3 mm) (ZMUC M58), Jolo, Philippines; I, female (9.5 × 7.3 mm) (ZRC 2013.1705), Lombok, Indonesia. A, male abdomen; B, left third maxilliped; C, frontal view of carapace showing antennules, antennae, epistome and orbit; D, E, left G1; F, G, distal part of left G1; H, left G2; I, female abdomen. Scales: A–C, I = 1.0 mm; D, E, H = 0.5 mm; F, G = 0.1 mm.

FIGURE 17. Raoulia piroculata (Rathbun, 1911), lectotype female (7.3 × 5.5 mm) (USNM 41359a), Amirante Is., Indian Ocean. A, dorsal view; B, anterior thoracic sternum and sterno-abdominal cavity; C, frontal view of carapace; D, posterior thoracic sternum; E, outer view of right chela; F, outer view of left chela.

FIGURE 18. Raoulia galea sp. nov., holotype male (9.4 × 7.4 mm) (ZRC 2000.0980), Phuket, Thailand. A, dorsal view; B, anterior thoracic sternum and sterno-abdominal cavity; C, frontal view of carapace; D, posterior thoracic sternum; E, outer view of right chela; F, outer view of left chela.

FIGURE 19. A–E, Raoulia piroculata (Rathbun, 1911), male (11.0 × 8.5 mm), South Africa; F–L, Raoulia galea sp. nov., holotype male (9.4 × 7.4 mm) (ZRC 2000.0980), Phuket, Thailand. A, male abdomen; B, left third maxilliped; C, D, left G1; E, F, distal part of left G1; G, left G2. Scales: A, B = 1.0 mm; C, D, G = 0.5 mm; E, F = 0.1 mm. A–E after Barnard (1955: fig. 16).