Parasesarma kui 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 kui

description: Parasesarma kui n. sp.
(Figs. 9, 10, 19D, 20C, 21D, 22C, 23C, 24D, 25G)
Material examined. HOLOTYPE: male (14.7× 13.7 mm) (NMNS-7779-015), Taiwan: Pingtung: Kenting National Park: mouth of Kangkou River (on Talipariti tiliaceum (L.) Fryxell), 30 September 2015, J.- J. Li. PARATYPES: 1 male (12.6×11.0 mm) (NMNS-7779-016), Taiwan: Pingtung: Kenting National Park: mouth of Kangkou River, 20 November 2016, J.- J. Li. — 1 male (14.5× 13.4 mm) (NMNS-7779-017), Taiwan: Pingtung: Kenting National Park: mouth of Kangkou River, 3 May 2016, J.- J. Li. — 1 male (15.6×14.0 mm) (NMNS-7779-018), Taiwan: Pingtung: Kenting National Park: mouth of Kangkou River, 16 October 2015, J.- J. Li. — 1 male (16.7× 14.8 mm) (NMNS- 7779-019), Taiwan: Pingtung: Kenting National Park: mouth of Kangkou River, 22 June 2016, J.- J. Li. — 1 female (12.5× 11.3 mm) (ZRC 2018.0790), Taiwan: Pingtung: Paoli River, 14 August 2015, J.- J. Li. —1 male (15.1× 14.1 mm), 1 female (8.0× 7.1 mm) (NMNS-7779-021), Taiwan: Pingtung: Kenting National Park: mouth of Kangkou River, 1 May 2016, J.- J. Li. — 1 male (14.6× 13.2 mm) (NMNS-7779-022), Taiwan: Pingtung: Kenting National Park: mouth of Kangkou River, 21 March 2016, J.- J. Li. — 2 males (15.3× 13.6 mm, 14.2× 12.5 mm) (NMNS-7779- 023), Taiwan: Pingtung: Pingtung: Kenting National Park: mouth of Kangkou River, 1 November 2015, J.- J. Li. — 1 male (16.5×15.0 mm) (NMNS-7779-024), Taiwan: Pingtung: Kenting National Park: mouth of Kangkou River, 18 June 2016, J.- J. Li. — 1 male (15.1× 13.9 mm) (ZRC 2018.0791), Taiwan: Pingtung: Kenting National Park: mouth of Kangkou River, 10 August 2016, J.- J. Li. — 2 males (15.6× 13.9 mm, 13.4× 14.2 mm) (ZRC 2018.0792), Taiwan: Pingtung: Kenting National Park: mouth of Kangkou River, 1 October 2015, J.- J. Li.
Diagnosis. Carapace (Figs. 9A, E, 10A, 22C) 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. 9C, D), 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. 9A, E, 10A, 22C). 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 other tubercles large, distalmost tubercle indistinct (Figs. 10C, D, 19D). 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. 20C). G1 relatively stout (Figs. 10E–H, 21D); apical process corneous, short, bent at angle of 45°, stout, ending in rounded tip. G2 longer than quarter length of G1 (Fig. 21D).
Colour in life. In large males and females from Taiwan, the carapace is almost black, mottled with yellowish or greenish orange blotches. Juveniles are light brown throughout, with some juveniles possessing light orange blotches on the cardiac region. The chelipeds are white and the fingers orange. The ambulatory legs are gray to brown (Figs. 22C, 23C, 24D).
Remarks. Parasesarma kui n. sp. occurs sympatrically with P. macaco n. sp. in several areas of Taiwan, but can easily be distinguished by the orange colour on the finger tips when alive (Figs. 23C, 25G) (both chelae and fingers organge for P. macaco n. sp., Figs. 23B, 25B), the slightly concave frontal margin (Figs. 9A, E, 10A) (strongly concave in P. macaco n. sp., Figs. 7A, E, 8A), as well as the number of dactylar tubercles of the chela (10 in P. kui n. sp.; 6–8 in P. macaco n. sp.). Parasesarma kui n. sp. juvenile are morphologically most similar to P. parvulum n. sp., but the latter species can easily be separated from P. kui by the dense brush of setae on the coxae of P3 and P4 (Fig. 15E). This dense coxal brush of setae is always absent in P. kui n. sp. regardless of the ontogenetic stages. Differentiating characters among this new species and the other close relatives are summarized in Table 1.
Etymology. Named for Mr. Ching-Fang Ku, a ranger in the Kenting National Park and specialist of land crab conservation. The type locality of P. kui n. sp., Kangkou River, is found in his home village of Kangkou.
Distribution. So far known from southern Taiwan (Kangkou and Paoli River).
Ecology. In Taiwan, Parasesarma kui n. sp. lives sympatrically with P. macaco n. sp. and Metopograpsus latifrons (Grapsidae), in the Paoli River. Its habitat and behavior are similar to that of P. macaco n. sp., and it often climbs on Pandanus tectorius in the Kangkou River as well (Figs. 25F, G). Some behavioral differences were observed between P. kui n. sp. and P. macaco n. sp. in Taiwan: P. kui n. sp. seems to prefer water of a lower salinity (0–15 ppt) and tends to inhabit relatively broader branches of the mangrove trees, and environments with higher humidity (around 87%). Parasesarma macaco n. sp. on the other hand, occurs in more saline waters (around 30 ppt) and prefers more slender branches and environments with a lower humidity. A study of the microhabitat preferences of these species is being conducted by the first author and Yi-Shin Chian (National Ping Tung University of Science and Technology, Taiwan).
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 466-469, DOI: 10.11646/zootaxa.4482.3.2, http://zenodo.org/record/1440707