Parasesarma tarantula Li & Rahayu & Ng 2018, n. sp.
Creators: name: Li, Jheng-Jhang
name: Rahayu, Dwi Listyo
name: Ng, Peter K. L.
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Sesarmidae
Parasesarma
Parasesarma tarantula

description: Parasesarma tarantula n. sp.
(Figs. 17, 18, 19H, 20G, 21H, 22E, 23E, 24F)
Material examined. HOLOTYPE: male (13.4× 11.5 mm) (MZB Cru 4801), Sulawesi: Bitung, 2 April 2017, J.-J. Li et al. PARATYPES: 3 males (12.6× 10.9 mm, 8.6× 7.6 mm, 8.2×7.0 mm) (ZRC 2018.0801), same data as holotype.—2 males (9.6× 7.9 mm, 6.7× 5.7 mm), 1 female (11.9× 10.1 mm) (MZB Cru 4802), same data as holotype.— 1 ovigerous female (11.2× 9.6 mm) (ZRC 2018.0802), same data as holotype.
Diagnosis. Carapace (Figs. 17A, F, 18A) squarish in general outline, 1.2 times broader than long; regions well defined, separated by shallow grooves; postfrontal region distinct, separated into 4 lobes by deep grooves; frontal margin slightly concaves in dorsal view; lateral margin straight, subparallel along most of length before curving to join almost straight posterior carapace margin; cornea extending or just reaching tip of external orbital tooth (Figs. 17A, F, 18A). Ischium of third maxilliped with shallow median sulcus, merus with distinct submedian ridge; exopod slender, tip reaching half-length of outer margin of merus, flagellum long. Male cheliped palm with 2 transverse pectinate crests (11 and 10 corneous teeth, distal and proximal crests, respectively) on upper surface; upper surface of dactylus with 10–12 symmetrical, obliquely elongate dactylar tubercles, proximal tubercles steep, sharp, other tubercles large, distalmost tubercle indistinct (Figs. 18C, D, 19H). Ambulatory legs relatively stout for this species-complex, P3 about 1.5 times carapace width; P3 and P4 coxae without dense setae; P3 merus 2.3 times as long as broad; P3 propodus 3.9 times as long as broad; P3 dactylus 0.5 times length of propodus (Fig. 20G). G1 relatively slender (Figs. 18E–H, 21H); apical process corneous, short, bent at angle of 45°, long, stout, ending in rounded tip. G2 longer than quarter length of G1 (Fig. 17E, 21H).
Colour in life. Similar to P. gecko n. sp., colour in general is dark brown. Carapace mottled dark and light brown, chelipeds brownish yellow, ambulatory legs light brown (Figs. 22E, 23E, 24F).
Remarks. The discovery of Parasesarma tarantula n. sp. from Sulawesi is unexpected. The species was found in Bitung, a site very close to Lembeh Island, the type locality of P. limbense. Parasesarma limbense was found originally in Lembeh Island, but we were not found in Bitung, suggesting that the types may have been collected in a different microhabitat Having two species of a species-complex occurring nearby or even together is not without precedence: in Taiwan, P. kui n. sp. and P. macaco n. sp. also live sympatrically in some locations.
Parasesarma tarantula n. sp. most closely resembles P. gecko n. sp. in the carapace shape and live colouration. It differs from all other members of the species-complex in having the P3 propodus distinctly shorter (Fig. 20G). In addition, P. tarantula is easily separated from P. limbense by its prominently concave frontal margin, as well as its straight and elongated G1 (Figs. 18E–H, 21H).
Etymology. The name is from the old Italian common name for large spiders, tarantula. The use of the name here alludes to the tree-climbing habits of the new species, similar to many species of tarantula, some of which are also found in Sulawesi. Used as a noun in apposition.
Distribution. Only known from North Sulawesi, thus far.
Ecology. In Sulawesi, Parasesarma tarantula n. sp. is often observed climbing on mangrove trees and dead wood above the water. They can also found in tree holes near the water level. They are generally active during the daytime.
description: Published as part of Li, Jheng-Jhang, Rahayu, Dwi Listyo & Ng, Peter K. L., 2018, Identity of the tree-spider crab, Parasesarma leptosoma (Hilgendorf, 1869) (Decapoda: Brachyura: Sesarmidae), with descriptions of seven new species from the Western Pacific, pp. 451-490 in Zootaxa 4482 (3) on pages 476-478, DOI: 10.11646/zootaxa.4482.3.2, http://zenodo.org/record/1440707