Heteropilumnus satriai Yeo, Rahayu and Ng, 2004

Ng, Peter K. L., Lin, Chia-Wei & Ho, Ping-Ho, 2018, Psammoecus hiranoi Yoshida and Hirowatari 2013, Zoological Studies 57 (12), pp. 1-17 : 3-7

Heteropilumnus satriai Yeo, Rahayu and Ng, 2004

( Figs. 1 D-F, 5-9)

Heteropilumnus satriai Yeo, Rahayu and Ng, 2004: 80 , fig. 1; Ng et al. 2008: 140.

Material examined: Holotype - male (19.3 × 13 mm) ( MZB Cru 1668), station EA-D 11, rocky islet southeast of Pulau Laut , Natuna Island , Indonesia, coll. Anambas Expedition, 16 March 2002. Others - 1 male (11.1 × 8.2 mm) ( NMMBCD4085 ), under rock with sandy substrate, Hojie , Kentin , 21°57.432'N 120°42.631'E, southern Taiwan, by SCUBA, coll. C.-W. Lin, 8 July 2013; 1 male (18.3 × 13.0 mm) ( ZRC 2017.1043 ), under rock with sand substrate, Houbihu, Kentin, Taiwan, by SCUBA, coll. C.-W. Lin, 8 June 2016; 2 females (16.1 × 11.9 mm, 6.8 × 5.4mm), Lutao (= Green Island), southern Taiwan, by SCUBA, coll. C.- W. Lin, 24 June 2017; 1 female (11.4 × 8.2 mm) ( NMMBCD4086 ), under large rock, sand substrate, Lutao (= Green Island), southern Taiwan, by SCUBA, coll. C.-W. Lin, 16 August 2017.

Colour: The colour and patterning in H. satriai in life is similar to that of H. decharmoyi except that the red patches on the ambulatory legs are relatively smaller and more uneven ( Figs. 1D, E ). There is some variation in this species, from having the red colour cover most of the carapace ( Fig. 1D ) to only covering less than half the surface ( Fig. 1E ), to the carapace and pereopods being mostly yellowish-white with only small patches of orange in small specimens ( Fig. 1F ).

Remarks: This species was described from one male, which was parasitized by a rhizocephalan and collected from the Indonesian Natuna Islands in the South China Sea ( Yeo et al. 2004). No colour notes were available at the time. The specimens from Taiwan now allow us a better understanding of its colour, morphological characters and variation.

The teeth on the anterolateral margin of smaller specimens (e.g., 11.1 × 8.2 mm, NMMBCD 4085) are less well defined, with the lobes relatively lower ( Fig. 6B ). In larger specimens (e.g., holotype male and male 18.3 × 13.0 mm, ZRC 2017.1043); the teeth are better defined and separated by more distinct clefts ( Figs. 5B , 6D ). The male pleon of the holotype male is atypical as the specimen was infected with a rhizocephalan ( Fig. 6F ). The pleon of the uninfected males is more triangular, with the telson semicircular in shape ( Figs. 7C, D , 8C, D ). The G1 of the present material varies slightly with size. In the larger male (18.3 × 13.0 mm, ZRC 2017.1043), the distal elongated part of the G1 is gently curved to relatively straight ( Figs. 9 A-C) whereas in the smaller male (11.1 × 8.2 mmm, NMMBCD 4085), it is gently sinuous with the tip gently curved upwards ( Figs. 9 E-G). The form of the G1 of the smaller male agrees very well with that figured by Yeo et al. (2004: fig. 1e, f) for the holotype.

The differences between H. satriai and H. decharmoyi have been discussed under the latter species. Heteropilumnus satriai is also similar to H. granulimanus Ward, 1933 , described from one male measuring 12.0 × 9.0 mm from the Capricorn Group of islands in Queensland, Australia. In H. granulimanus ; however, the frontal margin is more truncate with the two lobes separated by a narrow fissure ( Ward 1933: pl. 2 fig. 3) (vs. the two frontal lobes separated by a distinct V-shaped cleft in H. satriai , Figs. 5B , 6B, D ); the granules on the outer surface of the chela are more rounded, densely packed and arranged in rows ( Ward 1933: pl. 2 fig. 4) (vs. the granules are rounded to conical and distributed evenly on surface in H. satriai , Figs. 5E , 7E ); and the male telson is relatively wider ( Ward 1933: pl. 2 fig. 4) (vs. less wide in in H. satriai , Figs. 7C, D ).

Distribution: The species was described from the Natunas Islands in Indonesia, in the South China Sea ( Yeo et al. 2004), and is now recorded from Taiwan.

Figures

Fig. 1. Colour in life. A, Heteropilumnus decharmoyi (Bouvier, 1915), male (16.8 × 12.7 mm) (NMNST); B, H. decharmoyi (Bouvier, 1915), male (13.3 × 9.3 mm) (NMMBCD4084); C, H. satriai Yeo, Rahayu and Ng, 2004, male (18.3 × 13.0 mm) (ZRC 2017.1043); D, H. satriai Yeo, Rahayu and Ng, 2004, female (16.1 × 11.9 mm) (NMMBCD4086); E, H. satriai Yeo, Rahayu and Ng, 2004, male (11.1 × 8.2 mm) (NMMBCD4085); F, H. satriai Yeo, Rahayu and Ng, 2004, male (6.8 × 5.4 mm) (NMMBCD4086).

Fig. 6. Heteropilumnus satriai Yeo, Rahayu and Ng, 2004. A, B, E, male (11.1 × 8.2 mm) (NMMBCD4085); C, D, F, male (18.3 × 13.0 mm) (ZRC 2017.1043). A, C, overall view; B, D, right side of carapace (denuded); E, F, right fourth ambulatory leg. © 2018 Academia Sinica, Taiwan

Fig. 5. Heteropilumnus satriai Yeo, Rahayu and Ng, 2004, male (19.3 × 13 mm) (MZB Cru 1668), Indonesia. A, overall view; B, right side of carapace (denuded); C, frontal view of cephalothorax (right side denuded); D, right third maxilliped (denuded); E, outer view of chelae; F, anterior thoracic sternum and pleon; G, right fourth ambulatory leg.

Fig. 7. Heteropilumnus satriai Yeo, Rahayu and Ng, 2004, male (11.1 × 8.2 mm) (NMMBCD4085). A, frontal view of cephalothorax (right side denuded); B, left third maxilliped (denuded); C, anterior thoracic sternum and pleon; D, pleon; E, outer view of chelae. © 2018 Academia Sinica, Taiwan

Fig. 8. Heteropilumnus satriai Yeo, Rahayu and Ng, 2004, male (18.3 × 13.0 mm) (ZRC 2017.1043). A, frontal view of cephalothorax (right side denuded); B, left third maxilliped (denuded); C, anterior thoracic sternum and pleon; D, pleon; E, outer view of pleon. © 2018 Academia Sinica, Taiwan

Fig. 9. Heteropilumnus satriai Yeo, Rahayu and Ng, 2004, gonopods. A-D, male (18.3 × 13.0 mm) (ZRC 2017.1043); E-H, male (11.1 × 8.2 mm) (NMMBCD4085). A, E, left G1 (ventral view); B, F, distal part of left G1 (ventral view); C, G, distal part of left G1 (dorsal view); D, H, left G2. Scale bars = 0.5 mm.