Parasesarma parvulum, 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 : 474

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.5986797
persistent identifier	https://treatment.plazi.org/id/376A1B4D-FFB3-FF91-D1CD-FD01465FF814
treatment provided by	Plazi
scientific name	Parasesarma parvulum
status	sp. nov.

Treatment

Parasesarma parvulum View in CoL n. sp.

( Figs. 15 View FIGURE 15 , 16 View FIGURE 16 , 19G View FIGURE 19 , 20F View FIGURE 20 , 21G View FIGURE 21 )

Material examined. HOLOTYPE: Male (9.6× 8.4 mm) ( NMCR 50702 About NMCR ), Naujan, Mindoro Island, Philippines, 5 March 2016, W.- B. Chan . PARATYPES: 5 males (10.0× 8.7 mm, 9.9× 8.4 mm, 8.0×6.0 mm, 7.8× 6.8 mm, 7.8× 6.8 mm), 4 females (9.9× 8.2 mm, 9.4× 8.2 mm, 8.8× 7.4 mm, 8.6× 7.3 mm) ( NMCR 50703 About NMCR ), same data as holotype .—3 males (10.7× 9.7 mm, 10.1× 8.7 mm, 10.1× 8.6 mm), 4 females (11.3× 9.6 mm, 9.7× 8.5 mm, 9.3× 8.1 mm, 9.0× 7.8 mm) (NMNS-7779-026), same data as holotype .—2 males (7.8× 6.8 mm, 8.5× 7.4 mm), 1 female (11.4× 9.8 mm) ( ZRC 2018.0800 View Materials ), same data as holotype .

Diagnosis. Carapace ( Figs. 15A, F View FIGURE 15 , 16A View FIGURE 16 ) squarish in general outline, 1.1 times broader than long; regions well defined, separated by shallow grooves; postfrontal region distinct, separated into 4 lobes by deep grooves; front deflexed downwards ( Figs. 15C, D View FIGURE 15 ) margin slightly concave in dorsal view; lateral margin straight, converging posteriorly; cornea extending or just reaching tip of external orbital tooth ( Figs. 15A, F View FIGURE 15 , 16A View FIGURE 16 ). 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 (18 and 10 corneous teeth, distal and proximal crests, respectively) on upper surface; upper surface of dactylus with 10 symmetrical, obliquely elongate dactylar tubercles, proximal tubercles steep, sharp, the others tubercles large, distalmost tubercle indistinct ( Figs. 16C, D View FIGURE 16 , 19G View FIGURE 19 ). Ambulatory legs relatively slender for this species-complex, P3 and P4 about 1.5 times carapace width; P3 and P4 coxae with dense setae; P3 merus 2.5 times as long as broad; P3 propodus 4.8 times as long as broad; P3 dactylus 0.4 times length of propodus ( Fig. 20F View FIGURE 20 ). G1 relatively stout ( Figs. 16E–H View FIGURE 16 , 21G 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. 21G View FIGURE 21 ).

Colour in life. Colour in general is similar to P. macaco n. sp. (W.-B. Chan, pers. comm.).

Remarks. Parasesarma parvulum n. sp. morphologically resembles juveniles of P. kui n. sp. but can still be distinguished by the granulation on outer surface of palm is relatively minute and the coxae of P3 and P4 with dense setae (see Table 1).

Etymology. The name parvulum derives from the Latin word, meaning young or small, alluding to the relative small size of the present species.

Distribution. So far known from Kalinisan, in Naujan, Oriental Mindoro province, Mindoro Island, Philippines.

Ecology. In Philippines, most of the specimens of P. parvulum found were observed climbing on the mangrove trees Bruguiera gymnorhiza (L.) Lam. and Avicennia marina (Forsk.) Vierh. along the river banks of the estuary, and occurs sympatrically with Parasesarma macaco n. sp. and Metopograpsus latifrons (Grapsidae) (W.-B. Chan, pers. comm.).