Johora hoiseni Ng & Takeda, 1992

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
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treatment provided by	ZooKeys by Pensoft
scientific name	Johora hoiseni Ng & Takeda, 1992
status

Treatment

Johora hoiseni Ng & Takeda, 1992 Figures 1D View Figure 1 , 2D View Figure 2 , 3D View Figure 3 , 4D View Figure 4 , 5D View Figure 5 , 8E-H View Figure 8 , 12D View Figure 12 , 13D View Figure 13 , 14D View Figure 14

Potamiscus (Johora) johorensis tahanensis Bott, 1966: 495 (part), fig. 32 (not Stoliczia (Johora) johorensis tahanensis Bott, 1966 s. str.).

Stoliczia (Johora) johorensis tahanensis - Bott 1970: 181 (part), pl. 40 fig. 57; Ng and Tan 1984: 172, fig. 7 (not Stoliczia (Johora) johorensis tahanensis Bott, 1966).

Johora tahanensis - Ng 1987: 33 (part), fig. 9B-K; Ng 1988: 42 (part), fig. 18A, B, D, E, G (not Stoliczia (Johora) johorensis tahanensis Bott, 1966).

Johora hoiseni Ng & Takeda, 1992: 108, figs 2, 3; Ng 2004: 321; Ng and Yeo 2007: 100; Ng et al. 2008: 163; Cumberlidge et al. 2009: table.

Material examined.

Holotype: male (25.1 × 21.1 mm) (ZRC 1984.6673), stream entering Sungei Galas, near Gua Madir, Taman Negara National Park, Kelantan, ca. 4°51'30"N, 102°03'23"E, coll. Tweedie MWF, August 1939. Paratypes: 53 males, 13 females (ZRC 1984.6674-6755), same data as holotype. Others: 3 males, 18 females (ZRC 1984.7683-7687), stream entering Sungei Galas, near Gua Madir, Taman Negara National Park, Kelantan, ca. 4°51'30"N, 102°03'23"E, coll. Tweedie MWF, August 1939; 2 males, 5 females (ZRC 1989.3617-3623), Pahang or Kelantan?, no other data. All locations in Peninsular Malaysia.

Diagnosis.

Adult carapace width to length ratio 1.16-1.19 (Figs 1D View Figure 1 , 2D View Figure 2 , 12D View Figure 12 ); dorsal surface gently convex in frontal view, not inflated (Fig. 3D View Figure 3 ); frontal margin slightly sinuous to almost straight (Fig. 2D View Figure 2 ); suborbital, pterygostomial and sub-branchial regions rugose, pterygostomial region covered with dense setae (Fig. 3D 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. 2D View Figure 2 ); external orbital tooth separated from epibranchial tooth by distinct cleft, epibranchial tooth sharp, distinct (Fig. 2D View Figure 2 ); anterolateral margin gently convex (Fig. 2D View Figure 2 ); posterolateral margin medially concave to sinuous, gently converging towards gently convex, entire posterior carapace margin (Fig. 2D View Figure 2 ); posterior margin of epistome with triangular median triangle, lateral margin obliquely sloping (Fig. 3D View Figure 3 ); outer surfaces of third maxillipeds with dense, long stiff setae; ischium subrectangular, with shallow median oblique groove (Figs 3D View Figure 3 , 4D View Figure 4 ); ambulatory legs not elongate, length to width ratio of merus of fourth ambulatory leg 2.7-2.8 (Figs 1D View Figure 1 , 12D View Figure 12 ); G1 subterminal segment with broad proximal part, tapering suddenly to slender distal part, with distinct shelf-like structure along outer margin; terminal segment straight, ca. two-thirds length of subterminal segment, surfaces with numerous short setae (Fig. 8E-G View Figure 8 ); G2 slightly longer than G1, distal segment long, about half length of basal segment (Fig. 8H View Figure 8 ). Female pleon ovate; somite 3 less wide than somite 4, somites 4-6 progressively narrower; telson semicircular (Fig. 13D View Figure 13 ). Vulvae large, on anterior half of sternite 6, slightly pushing into suture with sternite 5, lateral sternal vulvar cover semicircular (Fig. 14D View Figure 14 ).

Remarks.

Ng and Takeda (1992) showed that the G1 differences of the material that had been identified as " J. tahanensis " by Bott (1966, 1970; Ng 1987, 1988) belong to a distinct species, J. hoiseni (see remarks for J. tahanensis ).

Distribution.

Johora hoiseni is known from the drainages near Gua Musang in Kelantan, in the northwestern part of Taman Negara National Park (Fig. 15 View Figure 15 ).

Conservation.

The species is not under any immediate threat as it is found in Malaysia’s oldest and largest national park. Ng and Yeo (2007) treated the species as endangered as it is only known from a relatively small geographic area but Cumberlidge et al. (2009) listed it as of least concern as it is in a protected area.