Johora booliati, Ng, 2020

Ng, Peter K. L., 2020, Revision of the freshwater crabs of the Johora tahanensis (Bott, 1966) species group (Crustacea, Brachyura, Potamidae), with a key to the genus, ZooKeys 994, pp. 1-34 : 1

publication ID	https://dx.doi.org/10.3897/zookeys.994.56810
publication LSID	lsid:zoobank.org:pub:DB1879C9-1904-4320-BE67-4D9F863F6775
persistent identifier	https://treatment.plazi.org/id/8A3C9173-A7A5-4559-92D7-A548453C6688
taxon LSID	lsid:zoobank.org:act:8A3C9173-A7A5-4559-92D7-A548453C6688
treatment provided by	ZooKeys by Pensoft
scientific name	Johora booliati
status	sp. nov.

Treatment

Johora booliati sp. nov. Figures 1F View Figure 1 , 2F View Figure 2 , 3F View Figure 3 , 4F View Figure 4 , 5F View Figure 5 , 10E-I View Figure 10 , 12F View Figure 12 , 13F View Figure 13 , 14F View Figure 14

Johora tahanensis - Takeda & Ng, 1992: 107 (part); Ng 1995: 249 (part) (not Stoliczia (Johora) johorensis tahanensis Bott, 1966).

Material examined.

Holotype: male (34.6 × 30.0 mm) (ZRC 2020.0072), stream next to house, under rocks, in old farmland and secondary forest, Bukit Tinggi village, west side of northbound Karak Highway, ca. 480 m a.s.l., Bentong District, Pahang, 3°22'3.0396"N, 101°48'50.994"E, coll. July 2016. Paratype: 1 female (40.4 × 34.4 mm) (ZRC 1995.270), in shallow stream with leaf litter, The Gap, Fraser’s Hill, 853 m a.s.l., Pahang, ca. 3°41'29"N, 101°44'56"E, coll. Lim KKP, 1 June 1990; 1 juvenile male (10.5 × 9.1 mm) (ZRC 2020.0364), under rocks, first stream on road towards Raub, descending from Fraser’s Hill, Pahang, coll. Lai JCY, 6 December 2015. All locations in Peninsular Malaysia.

Diagnosis.

Adult carapace width to length ratio 1.15-1.17 (Figs 1F View Figure 1 , 2F View Figure 2 , 12F View Figure 12 ); dorsal surface gently convex in frontal view, not inflated (Fig. 3F View Figure 3 ); frontal margin almost straight (Fig. 2F View Figure 2 ); suborbital, pterygostomial and sub-branchial regions rugose, pterygostomial region covered with dense setae (Fig. 3F View Figure 3 ); epigastric cristae distinct, distinctly anterior to sharp postorbital cristae, postorbital cristae with lateral edges low, joining lateral margin through oblique striae (Fig. 2F View Figure 2 ); external orbital tooth separated from epibranchial tooth by distinct cleft, epibranchial tooth sharp, distinct (Fig. 2F View Figure 2 ); anterolateral margin gently convex (Fig. 2F View Figure 2 ); posterolateral margin gently sinuous to almost straight, gently converging towards sinuous posterior carapace margin with shallow median indentation (Fig. 2F View Figure 2 ); posterior margin of epistome with triangular median triangle, lateral margin obliquely sloping (Fig. 3F View Figure 3 ); outer surfaces of third maxillipeds with dense, long stiff setae; ischium subrectangular, with shallow median oblique groove (Figs 3F View Figure 3 , 4F View Figure 4 ); ambulatory legs not elongate, length to width ratio of merus of fourth ambulatory leg 2.7-2.8 (Figs 1F View Figure 1 , 12F View Figure 12 ); G1 subterminal segment with broad proximal part, tapering relatively suddenly to slender distal part, with low shelf-like structure on outer margin; terminal segment gently curved outwards (from median part of sternum), less than half length of subterminal segment, surfaces with numerous short setae (Fig. 10E-H View Figure 10 ); G2 slightly longer than G1, distal segment long, about half length of basal segment (Fig. 10I View Figure 10 ). Female pleon ovate; somite 3 less wide than somite 4, somites 4-6 progressively narrower; telson semi-circular (Fig. 13F View Figure 13 ). Vulvae large, on anterior half of sternite 6, slightly pushing into suture with sternite 5, lateral sternal vulvar cover semi-circular (Fig. 14F View Figure 14 ).

Etymology.

The species is named after an old friend and mentor, the late Dr Lim Boo Liat (1926-2020), one of Malaysia’s most eminent biologists and naturalists. In a remarkable career spanning 70 years, he has contributed immensely to biodiversity and conservation science in Malaysia; more importantly, he has inspired, mentored, and trained many generations of biologists, many who now lead science in Malaysia and Singapore.

Remarks.

The large adult size of J. booliati sp. nov. and J. erici sp. nov. (carapace width in excess of 25 mm) with the pronounced epibranchial teeth allies them with J. tahanensis s. str., J. hoiseni , J. thaiana , J. thoi , J. tiomanensis , and J. counsilmani (the last two being endemic to Pulau Tioman, Peninsular Malaysia).

Johora booliati and J. erici resemble J. tahanensis , J. hoiseni , and J. thaiana in the carapace shape and general features. Their G1 structures, however, are different. In J. booliati and J. erici , the G1 subterminal segment is proportionately more elongate and the terminal segment is relatively shorter (Figs 10E-H View Figure 10 , 11A-C, E-G View Figure 11 ), and significantly, the terminal segment has only scattered short setae (versus subterminal segment shorter with the terminal segment longer and the surface of the latter more densely covered with short setae in J. tahanensis (Fig. 8A-C View Figure 8 ). Both J. hoiseni and J. thaiana have relatively straight G1 terminal segments which are prominently setose (Figs 8E-G View Figure 8 , 10A-C View Figure 10 ).

Johora booliati and J. erici can be distinguished from J. tiomanensis and J. counsilmani by their carapace being relatively more quadrate in shape (width to length ratio less than 1.2) and the adult carapace is distinctly wider than long (width to length ratio 1.3-1.4) in J. tiomanensis and J. counsilmani . In addition, the epigastric cristae of J. booliati and J. erici are distinctly anterior to the postorbital cristae and separated by a gap with the entire postorbital cristae sharp (Figs 2F, G View Figure 2 , 7B View Figure 7 ) while in J. tiomanensis and J. counsilmani , the epigastric cristae are only slightly anterior of the postorbital cristae and separated only by striae (cf. Ng and Tan 1984: figs 1A, 2A; Ng 1985: fig. 3). Most significantly, the G1 terminal segments of J. booliati and J. erici are proportionately stouter and less curved (Figs 10E-H View Figure 10 , 11A-C, E-G View Figure 11 ); in J. tiomanensis and J. counsilmani , it is distinctly slenderer, more elongate and strongly curved (cf. Ng and Tan 1984: fig. 3a-c; Ng 1985: figs 2a, c, e, 4a-c). Johora booliati and J. erici differ from J. thoi in possessing slightly shorter ambulatory legs (length to width ratio of merus of fourth leg 2.7-2.8 versus 3.0-3.2), the lateral carapace surfaces are relatively more rugose, and the distinctly shorter and gently curved G1 terminal segment (Figs 10E-H View Figure 10 , 11A-C, E-G View Figure 11 ); in J. thoi , this structure is diagnostic, being very elongate and straight (Fig. 9A-C, E-G View Figure 9 ).

The G1 structure of J. booliati closely resembles that of J. erici , with the terminal segments similar in shape and proportions. The G1 subterminal segments of the two species, however, differ in form, with that of J. booliati forming a shelf-like structure along the outer margin (Fig. 10E View Figure 10 ) while in J. erici , the tapering of the segment is gradual, and no shelf is visible (Fig. 11A, E View Figure 11 ). The carapaces of the two species are different in adult males and females. In J. booliati , the carapace has a more quadrate form because the anterolateral margin is only gently convex, even in the largest male and the posterolateral margin is straighter and gently converging, with the posterior carapace margin medially indented (even in females) (Fig. 2F View Figure 2 ). In J. erici , the carapace appears more ovate, with the anterolateral margin distinctly convex, and the posterolateral margin is medially concave and strongly converging, and the posterior carapace margin is entire (Figs 2G View Figure 2 , 7B View Figure 7 ).

The G1 structure of J. booliati and J. erici is superficially similar to that of J. murphyi from southern Peninsular Malaysia, notably in the shape of the G1 terminal and subterminal segments ( Ng 1986b: fig. 14a, b; 1987: fig. 6D, E; 1988: fig. 16D, E), but differs in having the distal part of the terminal segment more rounded and less sharply tapering (Figs 10E-H View Figure 10 , 11A-C, E-G View Figure 11 ). The G1 of J. booliati is also similar to J. intermedia , which has a wide distribution in central Peninsular Malaysia. The G1 terminal segment of J. booliati and J. erici , however, is relatively stouter and less curved, and the subterminal segment narrows along the distal third to form a neck-like structure with the terminal segment (Figs 10E-H View Figure 10 , 11A-C, E-G View Figure 11 ) (versus the G1 terminal segment is more curved and tapers to a slender tip with only the distalmost part of the subterminal segment distinctly narrowed to form a broad cleft in J. intermedia , cf. Ng 1987: figs 3A-D, G-J, 4A-D, F, G, I, J; 1988: fig. 15D-F; Ng and Takeda 1992: fig. 1A-E). It is also noteworthy that both J. murphyi and J. intermedia are smaller species than J. booliati and J. erici , with adults not reaching carapace widths of 25 mm.

Ng and Takeda (1992: 107) had specimens from Fraser’s Hill as well as adjacent areas (Sungei Gumut, Peretak, Selangor, 3°36'53.3"N, 101°44'40.4"E; Sungei Sum [probably Sungei Sum Sum], near Genting Highlands, Pahang, 3°20'42.2"N, 101°51'12.0"E; Ulu Teranum, Teras, Pahang, 3°44'12.6"N, 101°47'29.5"E) which they identified as " J. tahanensis ". On the basis of geography, they are probably all J. booliati as defined here.

Distribution.

Johora booliati sp. nov. is known from highland streams in the central highlands of Pahang (Genting Highlands, Bukit Tinggi and Fraser’s Hill) (Fig. 15 View Figure 15 ). The distribution of J. booliati overlaps with those of J. intermedia and J. gapensis , and we can expect the taxa to be found together. One juvenile male of J. booliati (10.5 × 9.1 mm, ZRC 2020.0364) was in fact collected with two adult males of J. intermedia at Fraser’s Hill (ZRC 2016.003).

Conservation.

The conservation status for J. booliati is not known as its actual distribution is not known. For the moment, it is known only from a 30 km stretch of hills along the Central Highlands of Peninsular Malaysia, in the area of Fraser’s Hill, Genting Highlands and Bukit Tinggi. This area is not protected, and in this context, the species should be categorised as vulnerable for the time being (see Cumberlidge et al. 2009).