Parasesarma macaco, 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 : 464-466

Parasesarma macaco n. sp.

( Figs. 7 , 8 , 19C , 20B , 21C , 22B , 23B , 24C , 25B–D )

Material examined. HOLOTYPE: male (13.8× 12.3 mm) (NMNS-7779-005), Taiwan: Pingtung: mouth of Paoli River, north bank (on Clerodendrum inerme (L.) Gaertn. ), 29 September 2015, J.- J. Li . PARATYPES: 1 male (12.3× 11.8 mm) ( ZRC 2018.0788 ), Taiwan: Pingtung: mouth of Paoli River , 5 July 2016, J.- J. Li. — 1 male (11.6×10.0 mm) ( ZRC 2018.0789 ), Taiwan: Pingtung: mouth of Paoli River , 30 September 2015, J.- J. Li. — 1 male (15.2× 13.4 mm) (NMNS-7779-008), Taiwan: Pingtung: mouth of Paoli River , 6 June 2016, J.- J. Li. — 1 male (13.9× 12.5 mm) (NMNS-7779-009), Taiwan: Pingtung: mouth of Kangkou River , 22 June 2016, J.- J. Li. — 1 male (9.7× 8.4 mm) (NMNS-7779-010), Mindoro , Philippines, 5 March 2016, W.- B. Chan. — 2 males (10.1× 8.9 mm, 12.9× 11.8 mm) (NMNS-7779-012), Taiwan: Pingtung: mouth of Paoli River , 19 March 2016, J.- J. Li. —1 male (12.8× 11.3 mm), 1 female (14.4×13.0 mm) (NMNS-7779-013), Taiwan: Tainan: Taijiang National Park : Sicao Mangrove Green Tunnel, South bank, 4 October 2015, J.- J. Li. — 1 female (12.7× 11.2 mm) (NMNS-7779- 014), Taiwan: Pingtung: mouth of Paoli River , 4 October 2016, J.- J. Li. — 1 male (12.4× 10.8 mm) (NMNS-7779- 007), Taiwan: Pingtung: Kenting National Park: mouth of Kangkou River , 26 September 2015, J.- J. Li. Other material : 2 males (12.7× 10.8 mm, 9.5× 10.9 mm), 3 females (12.3× 10.8 mm, 11.8×10.0 mm, 8.4× 7.5 mm) (NMNS- 7779-020), Philippines: Bohol Island: Loboc River , 18 May 2004, H.- C. Liu. — 1 male (9.9×8.4) (NMNS-7779- 011), Philippines: Mindoro , 5 March 2016, W.- B. Chan.

Diagnosis. Carapace ( Figs. 7A, E , 8A , 22B ) squarish in general outline, 1.1 times broader than long; regions well defined, separated by deep grooves; postfrontal region distinct, separated into 4 lobes by deep grooves; front deflexed downwards ( Figs. 7C, D ) margin intensely 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. 77A, E, 8A, 22B). 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 (13 and 10 corneous teeth, respectively) on upper surface; upper surface of dactylus with 6 to 8 (average 7) symmetrical, obliquely elongate dactylar tubercles, proximal 3 tubercles steep, sharp, the others tubercles large, distalmost 2 tubercles indistinct ( Figs. 8C , 19C ). Ambulatory legs relatively slender for this species-complex, P3 and P4 about 1.5 times carapace width; P3 and P4 coxae without dense setae; P3 merus 2.5 times as long as broad; P3 propodus 5.0 times as long as broad; P3 dactylus 0.4 times length of propodus ( Fig. 20B ). G1 relatively slender; apical process corneous, elongated, slightly bent at angle of 45°, long, stout, ending in rounded tip ( Figs. 8E, F , 21C ). G2 longer than quarter length of G1 ( Fig. 21C ).

Colour in life. In large individuals, the carapace is dark brown, mottled with darker and lighter blotches; females and juveniles occasionally have light orange blotches on the gastric region ( Fig. 25C ). Chelipeds are yellowish orange, but brighter in males. Ambulatory legs are gray to brown ( Figs. 22B , 23B , 24C ).

Remarks. Parasesarma macaco n. sp. is most easily separated from other members of the species-complex by the medially concave frontal margin, and in having 6–8 dactylar tubercles of the chela (all tubercles are counted, including the small proximal and obsolescent distal ones). The specimens from Bohol Island, Philippines, differ from the other specimens in having a slightly longer G1 but the tip is of the same shape. The features that distinguish this species from its closest congeners are summarized in Table 1.

Etymology. Derived from the Portuguese " macaco " meaning “monkey”. It alludes to the agility of this treeclimbing species and its habit of jumping around branches. The name is used as a noun in apposition.

Distribution. Taiwan: Kangkou River and Paoli River (Pingtung county) and Sicao (Tainan city); Philippines: Mindoro and Bohol Island.

Ecology. Parasesarma macaco n. sp. is a common species in Paoli River, Taiwan. In Taiwan and Philippines, most of specimens of P. macaco were collected at night, with specimens observed climbing the trees along the river banks of the estuary. The common host plants are Talipariti tiliaceum (L.) Fryxell, Clerodendrum inerme (L.) Gaertn. (in Taiwan) ( Figs. 25A–C ), Bruguiera gymnorhiza (L.) Lam. and Avicennia marina (Forsk.) Vierh. (in Philippines). When the water levels (from the rising tide and rainfall) reach the host plant, the crabs would climb downward and submerge in the water. Parasesarma macaco n. sp. rarely ventures onto the ground except for breeding ( Fig. 25D ). Ovigerous females were found almost all year around, but mainly in July to October.

Parasesarma macaco n. sp. occurs sympatrically with P. kui n. sp. ( Taiwan) and Metopograpsus latifrons ( Taiwan and Philippines), the niche and ecology appear to be generally similar (see “Ecology” for P. kui ).

Figures

FIGURE 7. Parasesarma macaco n. sp.. A–D, holotype male (13.8×12.3 mm) (NMNS-7779-005), Pingtung, Taiwan; E, F, paratype female (13.3×11.1 mm) (NMNS-7779-013), same locality. A, E, dorsal views; B, F, ventral views; C, D, frontal views.

FIGURE 8. Parasesarma macaco n. sp., holotype male (13.8×12.3 mm) (NMNS-7779-005), Pingtung, Taiwan. A, dorsal view of carapace; B–D, tip of left cheliped; E, F, left G1. B, lateral view of pectinated cristae on palm; C, dorsal view of palm and dactylar finger; D, lateral view of dactylar finger; E, dorsal (sternal) view; F, ventral (pleonal) view. Scale bars: 1.0 mm.

FIGURE 19. Outer views of chelae, holotype males. A, Parasesarma leptosoma (17.0×15.2 mm) (ZRC 2000.1718), Kenya; B, P. gecko n. sp. (16.2×14.6 mm) (RUMF-ZC-4710), Okinawa Island, Japan; C, P. macaco n. sp. (13.8×12.3 mm) (NMNS-7779- 005), Pingtung, Taiwan; D, P. kui n. sp. (14.7×13.7 mm) (NMNS-7779-015), Pingtung, Taiwan; E, P. gracilipes n. sp. (13.6×11.9 mm) (MZB Cru 4803), Papua, Indonesia; F, P. purpureum n. sp. (15.9×13.7 mm) (ZRC 2012.0755a), Tioman Island, Peninsular Malaysia; G, P. parvulum n. sp. (9.6×8.4 mm) (NMCR 50702), Mindoro Island, Philippines; H, P. tarantula n. sp. (13.4×11.5 mm) (MZB Cru 4801), Sulawesi, Indonesia.

FIGURE 20. First to fourth ambulatory legs (P2–P5) (from top to bottom), holotype males. A, Parasesarma gecko n. sp. (16.2×14.6 mm) (RUMF-ZC-4710), Okinawa Island, Japan; B, P. macaco n. sp. male (13.8×12.3 mm) (NMNS-7779-005), Pingtung, Taiwan; C, P. kui n. sp. (14.7×13.7 mm) (NMNS-7779-015), Pingtung, Taiwan; D, P. gracilipes n. sp. (13.6×11.9 mm) (MZB Cru 4803), Papua, Indonesia; E, P. purpureum n. sp. (15.9×13.7 mm) (ZRC 2012.0755a), Tioman Island, Peninsular Malaysia; F, P. parvulum n. sp. (9.6×8.4 mm) (NMCR 50702), Mindoro Island, Philippines; G, P. tarantula n. sp. (13.4×11.5 mm) (MZB Cru 4801), Sulawesi, Indonesia.

FIGURE 21. Gonopods of Parasesarma leptosoma species-complex. A, P. leptosoma (17.0×15.2 mm) (ZRC 2000.1718), Kenya; B, P. gecko n. sp., holotype (16.2×14.6 mm) (RUMF-ZC-4710), Okinawa, Japan; C, P. macaco n. sp., holotype (13.8×12.3 mm) (NMNS-7779-005), Pingtung, Taiwan; D, P. kui n. sp., holotype (14.7×13.7 mm) (NMNS-7779-015), Pingtung, Taiwan; E, P. gracilipes n. sp., holotype (13.6×11.9 mm) (MZB Cru 4803), Papua, Indonesia; F, P. purpureum n. sp., holotype (15.9×13.7 mm) (ZRC 2012.0755a), Tioman Island, Peninsular Malaysia; G, P. parvulum n. sp., holotype (9.6×8.4 mm) (NMCR 50702), Mindoro Island, Philippines; H, P. tarantula n. sp., holotype (13.4×11.5 mm) (MZB Cru 4801), Sulawesi, Indonesia.

FIGURE 22. Colour in life, males, dorsal views. A. Parasesarma gecko n. sp., holotype (16.2×14.6 mm) (RUMF-ZC-4710), Okinawa, Japan; B. P. macaco n. sp., holotype (13.8×12.3 mm) (NMNS-7779-005), Pingtung, Taiwan; C. P. kui n. sp. (14.7×13.7 mm) (NMNS-7779-015), Pingtung, Taiwan; D, P. purpureum n. sp. (13.4×11.8 mm) (ZRC 2018.0799), Borneo, Malaysia; E, P. tarantula n. sp. (13.4×11.5 mm) (MZB Cru 4801), Sulawesi, Indonesia.

FIGURE 23. Colour in life, males, ventral views. A. Parasesarma gecko n. sp., holotype (16.2×14.6 mm) (RUMF-ZC-4710), Okinawa, Japan; B. P. macaco n. sp., holotype (13.8×12.3 mm) (NMNS-7779-005), Pingtung, Taiwan; C. P. kui n. sp. (14.7×13.7 mm) (NMNS-7779-015), Pingtung, Taiwan; D, P. purpureum n. sp. (13.4×11.8 mm) (ZRC 2018.0799), Borneo, Malaysia; E, P. tarantula n. sp. (13.4×11.5 mm) (MZB Cru 4801), Sulawesi, Indonesia.

FIGURE 24. In situ photographs of Parasesarma leptosoma species-complex, specimens not collected. A, P. leptosoma (Hilgendorf, 1869), Kenya (Photograph: S. Cannicci); B, P. gecko n. sp., Okinawa, Japan; C, P. macaco n. sp., Pingtung, Taiwan; D, P. kui n. sp., Pingtung, Taiwan; E, P. purpureum n. sp., Borneo, Malaysia; F, P. tarantula n. sp., Sulawesi, Indonesia.

FIGURE 25. Habitats associated with Parasesarma macaco n. sp., P. gecko n. sp. and P. kui n. sp., specimens not collected. A–D, P. macaco n. sp., Pingtung (Paoli River), Taiwan; E, P. gecko n. sp., group of crabs on cement wall near mangrove, Okinawa, Japan; F, G, P. kui n. sp., Pingtung (Kangkou River), Taiwan. A, habitat constituted by Talipariti tiliaceum and Clerodendrum inerme; B, male climbing on T. tiliaceum; C, female climbing on C. inerme; D, ovigerous female during breeding migration; F, habitat constituted by T. tiliaceum; G, male climbing on shrubs.