Holthuija miersii ( Walker, 1887 )

Ng, Peter K. L. & Forges, Bertrand Richer De, 2015, Revision of the spider crab genus Maja Lamarck, 1801 (Crustacea: Brachyura: Majoidea: Majidae), with descriptions of seven new genera and 17 new species from the Atlantic and Indo-West Pacific, Raffles Bulletin of Zoology 63, pp. 110-225 : 161

publication ID	https://doi.org/ 10.5281/zenodo.5384590
publication LSID	lsid:zoobank.org:pub:40BCDD62-D35E-46D1-95A3-2CC0DF219DEE
persistent identifier	https://treatment.plazi.org/id/03A9654B-FFB2-076B-566A-FF3F7C15FB56
treatment provided by	Valdenar
scientific name	Holthuija miersii ( Walker, 1887 )
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Holthuija miersii ( Walker, 1887) View in CoL

( Figs. 2E View Fig , 24A–D View Fig , 27A–C View Fig , 37D, E View Fig , 40D, E View Fig , 42C View Fig , 46A View Fig , 50D, E View Fig , 52I View Fig , 54D View Fig , 56C View Fig , 69C, D View Fig )

Maia miersii Walker, 1887: 109 View in CoL , pl. 6, figs 1–3.

Maja miersi – Serène, 1968: 57. – Serène & Lohavanijaya, 1973: 50 (key).

Maja miersii View in CoL – Rathbun, 1924: 6. – Griffin, 1966a: 284 (key). – Griffin & Tranter, 1986: 217. – Ng et al., 2008: 117.

Material examined. Singapore – 1 female (21.4 × 16.7 mm) ( NHM 1900.10.22.13), Pasir Panjang, near Sungei Pandan, sandy mud, 6 fathoms, coll. F.P. Bedford & W.F. Lanchester , 1900. — 1 male (32.6 × 25.6 mm) ( ZRC 2000.1497 View Materials ), Southern Islands , dredge, coll. D. Lane , 1991. — 2 females (14.7 × 10.7 mm, 16.5 × 12.2 mm) ( ZRC 1995.311 View Materials ), dredged off Pulau Semakau , coll. P.K.L. Ng , 1991. — 1 male (20.1 × 14.7 mm) ( ZRC 1985.325 View Materials ), Damar Laut , station B54, 5–8 fms, mud with gorgonians, coll. Singapore Fisheries Research Station , 1955–56. — 1 male (22.3 × 16.5 mm) ( CBM-ZC4001 ), southern Singapore , coll. T. Komai, dredge, 9 May 1997 . — 1 ovigerous female (50.2 × 40.4 mm) ( ZRC 2013.1272 View Materials ), station 4714-TB2, Semakau Island , dredge, coll. Comprehensive Marine Biodiversity Survey team, RV Galaxea , 15 May 2013 .

Diagnosis. Carapace covered with small granules ( Fig. 24A–D View Fig ). Pseudorostral spines relatively short, diverging, curved outwards ( Fig. 37D, E View Fig ). Antorbital spine long, sharp; intercalated spine triangular, sharp; postorbital spine very long, sharp, slightly curved upwards; hepatic area with 2 sharp spines pointed outwards, first one longest ( Figs. 24A–D View Fig , 37D, E View Fig ). Lateral margin with 3 spines; 1 sharp branchial spine; 2 median spines: 1 gastric, 1 cardiac; 2 spines on posterior carapace margin ( Fig. 24A–D View Fig ). Basal antennal article granulated, with 2 long blunt spines distally ( Fig. 40D, E View Fig ). Epistome with 2 large tubercles on anterior margin ( Fig. 40D, E View Fig ). G1 strongly curved with small flap distally ( Fig. 27A–C View Fig ).

Remarks. Walker (1887) described Maia miersii from Singapore on the basis of a male 33 mm in carapace length (excluding pseudorostrum) ( Fig. 24A View Fig ). The largest male from Singapore examined here (ZRC 2000.1497) agrees well with his description and figures. The largest known specimen is a recently collected female specimen and differs from the smaller specimens in several features: the antorbital spine is directed somewhat more upwards, the posterior carapace spines are pointed more upwards, the ocular peduncle is relatively longer and more prominently curved upwards, it has two rows of large rounded granules starting from the basal antennal article to the epistome which are more prominent, the suborbital tooth is more strongly granulated, and the ambulatory legs are more setose. These differences are not significant and probably associated with its large size.

Tune Sakai (1938) first recorded this species as “ Maja miersi ” from Japan, and because material from Singapore (and Southeast Asia) has not been reported since, the Japanese accounts by T. Sakai and his colleagues (see synonymy for next species) are generally the ones used to define this taxon. Comparisons of material from Japan and Singapore show that while they are superficially resemble each other in having a relatively elongate carapace and similar arrangement of spines, their G1 structures are very different. The G1 of H. miersii s. str. is medially curved while that of the Japanese material is straight. In addition the two median spines on the posterior carapace margin are always short in the Japanese specimens while it is proportionately longer and stronger in H. miersii s. str. In addition, the subhepatic, pterygostomian and thoracic sternal surfaces are relatively more strongly granulated in H. miersii s. str. ( Fig. 50D, E View Fig ) compared to the less granulated condition in the Japanese material ( Fig. 50H View Fig ). The Japanese material previously identified as “ Maja miersi ” is here referred to Holthuija cognata n. sp. The G1 structure of H. cognata actually resembles that of H. pauli n. sp., but the two species have different carapace features.

Johnson (1958: 115) had checked on the type specimens of the four decapod species Walker described from Singapore, including Maia miersii , and noted that “none of them is present in there at the moment”. With Paul Clark , the second author searched the collections of NHM for Walker’s type male but could not locate the specimen. It is probably no longer extant, but a neotype is not necessary in light of the distinctive features of the species described here .

The recent specimen of H. miersii (ZRC 2013.1272) ( Fig. 69C, D View Fig ) was collected inside a large rock from around 20 m of water, in an area that is very rocky with very strong currents. This may be the preferred habitat of the species.

In life, the species is dull brown with patches of purple. The ambulatory dactyli are reddish brown; with parts of the ventral surfaces and abdomen purple ( Fig. 69C, D View Fig ).