Parasesarma purpureum, 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 : 471-474

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.5986795
persistent identifier	https://treatment.plazi.org/id/376A1B4D-FFB0-FF91-D1CD-F8F24053FD72
treatment provided by	Plazi
scientific name	Parasesarma purpureum
status	sp. nov.

Treatment

Parasesarma purpureum View in CoL n. sp.

( Figs. 13 View FIGURE 13 , 14 View FIGURE 14 , 19F View FIGURE 19 , 20E View FIGURE 20 , 21F View FIGURE 21 , 22D View FIGURE 22 , 23D View FIGURE 23 , 24E View FIGURE 24 )

Material examined. HOLOTYPE: male (15.9× 13.7 mm) ( ZRC 2012.0755 View Materials a), Peninsular Malaysia: Tioman Island , 7 July 2012, B.Y. Lee . PARATYPES: 3 males (10.7× 9.2 mm, 13.9×12.0 mm, 15.5× 13.3 mm), 4 females (12.6× 10.7 mm, 13.5×12.0 mm, 14.9× 12.7 mm, 15.6×13.0 mm) ( ZRC 2018.0794 View Materials ), same data as holotype. —3 males (11.9×10.0 mm, 12.7× 10.8 mm, 14.2× 12.8 mm), 4 females (10.9×9.0 mm, 12.1× 10.6 mm, 12.6× 10.5 mm, 14.0× 12.2 mm) ( ZRC 2018.0795 View Materials ), Peninsular Malaysia: Tioman Island , 4 July 2012, B.Y. Lee. —2 males (11.4×10.0 mm, 11.7× 9.8 mm), 1 female (13.5×11.2) ( ZRC 2018.0796 View Materials ), Peninsular Malaysia: Tioman Island , 5 July 2012, B.Y. Lee. —3 males (12.7× 10.8 mm, 13.1× 10.8 mm, 13.1× 10.9 mm), 3 females (12.3× 10.4 mm, 13.6× 11.5 mm, 16.1×14.0 mm) ( ZRC 2018.0797 View Materials ), Peninsular Malaysia: Tioman Island , 6 July 2012, B.Y. Lee. —1 male (12.2× 10.5 mm), 1 female (14.5×13.0 mm) ( ZRC 2012.0755 View Materials b), Peninsular Malaysia: Tioman Island , 7 July 2012, B.Y. Lee. —3 males (15.0× 13.5 mm, 13.4× 11.8 mm, 10.9× 9.8 mm), 2 females (13.9×13.6, 12.3×11.1) ( ZRC 2018.0799 View Materials ), Malaysia: Borneo : Sabah, 27 February 2018, J.- J. Li et al. . —1 male (12.6× 11.5 mm), 1 female (15.4× 13.8 mm) ( MZB Cru 4800), Malaysia: Borneo : Sabah, 27 February 2018, J.- J. Li et al. . — 1 male (13.7× 12.4 mm) (NMNS-7779-027), Malaysia: Borneo : Sabah, 27 February 2018, J.- J. Li et al. . — 2 males (14.5×13.0 mm, 14.3× 13.4 mm) ( NMCR 50704 View Materials ), Malaysia: Borneo : Sabah, 27 February 2018, J.- J. Li et al. .

Diagnosis. Carapace ( Figs. 13A, E View FIGURE 13 , 14A View FIGURE 14 , 22D View FIGURE 22 ) 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; front deflexed downwards ( Figs. 13C, D View FIGURE 13 ) margin slightly concave 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. 13A, E View FIGURE 13 , 14A View FIGURE 14 , 22D View FIGURE 22 ). 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 (12 and 7 corneous teeth, respectively) on upper surface; upper surface of dactylus with 9 or 10 symmetrical, obliquely elongate dactylar tubercles, proximal tubercles steep, sharp, the others tubercles large, distalmost tubercle indistinct ( Figs. 14C, D View FIGURE 14 , 19F View FIGURE 19 ). Ambulatory legs relatively slender for this species-complex, P3 and P4 about 1.6 times carapace width; P3 and P4 coxae without dense setae; P3 merus 2.6 times as long as broad; P3 propodus 4.4 times as long as broad; P3 dactylus 0.4 times length of propodus ( Fig. 20E View FIGURE 20 ). G1 relatively stout ( Figs. 14E–H View FIGURE 14 , 21F 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. 21F View FIGURE 21 ).

Colour in life. Carapace dark brown, fingers of chelipeds are pale white, ambulatory legs violet or purplish brown. ( Fig. 22D View FIGURE 22 , 23D View FIGURE 23 , 24E View FIGURE 24 ).

Remarks. Parasesarma purpureum n. sp., is most similar to P. kui n. sp. (from Taiwan) with regards to its relatively broader carapace. However, the following differences are observed; the carapace surface of P. purpureum has scattered tufts of short setae, the dactylar tubercles of the male chela are consistently nine in number ( Figs. 14D View FIGURE 14 , 19F View FIGURE 19 ,); the corneous tip of the G1 is proportionately broader ( Figs. 14E–H View FIGURE 14 ); and the general colour in life is dark purple, or brownish-purplish with white chelae ( Figs. 22D View FIGURE 22 , 23D View FIGURE 23 ). By contrast, in P. kui n. sp., the carapace surface is glabrous; the dactylar tubercles are nine or ten ( Figs. 10C, D View FIGURE 10 , 19D View FIGURE 19 ); the corneous tip of the G1 is proportionately narrower ( Figs. 10E–H View FIGURE 10 ), and in life, the colour of the carapace is black or light brown, with the chelae possessing orange fingers ( Figs. 22C View FIGURE 22 , 23C View FIGURE 23 ).

Etymology. From the Latin purpureum for “purple” with reference to the general colour of the new species.

Distribution. So far known from Tioman Island, Peninsular Malaysia; and Sabah, East Malaysia, Borneo.

Ecology. Parasesarma purpureum n. sp. in Malaysia (Tioman Island and Sabah) is often observed at night and climbing on mangrove tree trunks and aerial roots above the water level.