Parasesarma tarantula, Li & Rahayu & Ng, 2018

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, Zootaxa 4482 (3), pp. 451-490 : 476-478

publication ID	https://doi.org/ 10.11646/zootaxa.4482.3.2
publication LSID	lsid:zoobank.org:pub:3FBE11E2-9F97-4A29-92A9-67780C782E0D
DOI	https://doi.org/10.5281/zenodo.5986799
persistent identifier	https://treatment.plazi.org/id/376A1B4D-FFBD-FF9D-D1CD-FA1944CBFD8A
treatment provided by	Plazi
scientific name	Parasesarma tarantula
status	sp. nov.

Treatment

Parasesarma tarantula View in CoL n. sp.

( Figs. 17 View FIGURE 17 , 18 View FIGURE 18 , 19H View FIGURE 19 , 20G View FIGURE 20 , 21H View FIGURE 21 , 22E View FIGURE 22 , 23E View FIGURE 23 , 24F View FIGURE 24 )

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 View Materials ), 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 View Materials ), same data as holotype .

Diagnosis. Carapace ( Figs. 17A, F View FIGURE 17 , 18A View FIGURE 18 ) 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 View FIGURE 17 , 18A View FIGURE 18 ). 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 View FIGURE 18 , 19H View FIGURE 19 ). 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 View FIGURE 20 ). G1 relatively slender ( Figs. 18E–H View FIGURE 18 , 21H View FIGURE 21 ); apical process corneous, short, bent at angle of 45°, long, stout, ending in rounded tip. G2 longer than quarter length of G1 ( Fig. 17E View FIGURE 17 , 21H View FIGURE 21 ).

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 View FIGURE 22 , 23E View FIGURE 23 , 24F View FIGURE 24 ).

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 View FIGURE 20 ). 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 View FIGURE 18 , 21H View FIGURE 21 ).

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.