Cherax warsamsonicus, Lukhaup, Christian, Eprilurahman, Rury & Rintelen, Thomas von, 2017

Lukhaup, Christian, Eprilurahman, Rury & Rintelen, Thomas von, 2017, Cheraxwarsamsonicus, a new species of crayfish from the Kepala Burung (Vogelkop) peninsula in West Papua, Indonesia (Crustacea, Decapoda, Parastacidae), ZooKeys 660, pp. 151-167 : 152-160

Cherax warsamsonicus sp. n. Figs 1, 2, 3, 4, 5

Material examined.

Holotype: male (MZB Cru 4529), among roots along banks of a unnamed creek draining into Warsamson River, north of Sorong City, 0°49'16.62"S 131°23'3.34"E, West Papua, Indonesia. coll. Chris Lukhaup, Irianto Wahid and unnamed local guide January 20 2016. Allotype: female (MZB Cru 4530), same data as holotype. Paratypes: (MZB Cru 4531), same data as holotype.

Diagnosis.

Carapace surface smooth with four small spiniform tubercles posterior to cervical groove on lateral carapace. Eyes large, pigmented. Cornea slightly broader than eyestalk. Rostrum lanceolate in shape with excavated margins. Rostral margins with three prominent teeth. Rostral carinae prominent. Postorbital ridges prominent with one acute tubercle at anterior terminus. Uncalcified patch on lateral margin of chelae of adult male white, translucent. Propodal cutting edge with row of small granules and one large tubercle. Chelipeds blue and white with white joints. Fingers blue in distal third black with hooked tips. Other walking legs blue-gray. Pleon black with pinkish-red pattern. Lateral pleura lighter becoming greyish green.

Description of male holotype

(Figs 2-5).Body and eyes pigmented. Eyes not reduced. Body subovate, slightly compressed laterally. Pleon narrower then cepha lothorax (width 16.7 mm and 17.5 mm respectively). Rostrum (Fig. 3A) broad in shape, reaching nearly to end of ultimate antennular peduncle and one third longer than wide (width 5 mm at base, length 13.6 mm). Upper surface smooth, slightly scattered. Margins slightly elevated continuing in rostral carinae on carapace, almost straight in basal part, distally rather moderately tapering towards apex. Lateral rostral margin bearing three prominent teeth in distal half, pointing upwards at angle of approximately 45°. Few short hairs present on distal half of outer margins. Acumen with anteriorly orientated spine.

Rostral carinae extending as slight elevation posteriorly on carapace terminating at ending of postorbital ridges. Postorbital ridges well developed, terminating in spiniform tubercle anteriorly, fading at two-thirds of occipital carapace length, posteriorly. Dorsal surface of carapace smooth, slightly pitted, cervical and branchiocardiac grooves distinct, non-setose, one prominent corneous spine and three tubercles present at middle part behind cervical groove on lateral sides of carapace.

Areola length 13.7 mm, narrowest width 7.4 mm. Length of areola 31.8% of total length of carapace (43 mm).

Ventrolateral parts smooth with scattered pits; anterior margin strongly produced, rounded upper margin directed inward.

Scaphocerite (Fig. 3B) broadest at midlength, convex in distal part becoming narrower in basal part; thickened lateral margin terminating in large corneous spine, almost reaching distal margin of ultimate segment of antennular peduncle. Right scaphocerite 11 mm long and 4 mm wide. Proximal margins setose. Antennulae and antennae typical for genus. Antennae similarly long as body. Antennular peduncle reaching slightly behind acumen, antennal peduncle reaching slightly behind apex of scaphocerite. Antennal protopodite with spine anteriorly; basicerite with one lateral and one ventral spine.

Mouthparts typical for the genus. Epistome with subcordiform cephalic lobe anteriorly bearing lanceolate cephalomedian projection constricted at base. Lateral margins of lobe not thickened; each lateral margin with two groups of 8-9 tubercles separated by a smooth place. Central part smooth, not pitted, excavate. Eyes rather large; cornea globular, darkly pigmented, nearly as long as eyestalk; eyestalk slightly narrower than cornea.

First pereopod equal in form, chela slightly gaping, equal in size, right cheliped (39 mm long, 8.2 mm high, 16.5 mm wide). Left chelae (Fig. 3 C–D) 38.3 mm long and 8.2 mm high, 16.5 mm wide, strongly compressed. Fingers shorter than palm (dactylus 15.3 mm long). Dactylus broad at base (7 mm), tapering slightly towards tip.

Tip with sharp, corneous, hooked tooth pointing outwards at an angle of 45°. Cutting edge of dactyl with continuous row of rather small granular teeth and one prominent larger tooth at middle of cutting edge. Ventral and dorsal surface of movable finger with scattered punctuation. Posterior half of cutting edge with slightly rounded gap. Fixed finger triangular, merging gradually into palm, ending in sharp, corneous, hooked tooth, standing almost perpendicular to axis of finger. Tips of fingers slightly crossing when fingers clasp. Upper surface of palm practically smooth, slightly pitted, more densely pitted at margins. Fixed finger with approximately same width as dactyl at base (7.3 mm). Few scattered short setae present in posterior ventral part of fixed finger. Cutting edge of fixed finger with row of rather small granular teeth at posterior half and one at middle of anterior part.

Dorsal surface of carpus (11.77 mm) smooth and pitted, with slight excavation in middle part and with well-developed acute and hooked spiniform tubercle in middle of dorsolateral inner margin. Ventral carpal surface margins slightly elevated, non-setose and with fovea; inner margin with one acute spiniform tubercle oriented in angle of approx. 45°; outer margin smooth with one spiniform tubercle oriented almost anteriorly.

Merus (19.2 mm) laterally depressed in basal part; surface slightly pitted; one prominent spine at anterior part at dorsal surface. Row of 12-13 small granules on inner ventrolateral margin, four prominent spines, one at midlength other in middle of anterior part, third on distal ventrolateral outer margin, fourth on distal ventrolateral inner margin.

Ischium (10.8 mm) smooth with small spine and three granules at midlength of ventrolateral inner margin.

Second pereopod reaching anteriorly to approximately middle of scaphocerite. Finger as long as palm (5.6 mm), of same height. Short setae present on dactyl and fixed finger, getting denser anteriorly. Cutting edge of fixed finger and carpus with row of short setae. Carpus, smooth, not pitted, slightly longer than palm. Merus (12.7 mm) 1.7 times longer than carpus (7.2 mm). Ischium (6.2 mm) half as long as merus.

Third pereopod overreaching second by almost length of finger of second pereopods. Fingers shorter than palm.Fourth pereopod reaching distal margin of scaphocerite. Dactylus with corneous tip. Short scattered setae present. Propodus more than twice as long as dactylus, nearly 1.5 times as long as carpus; somewhat flattened, carrying many stiff setae on lower margin. Merus just slightly longer than propodus.

Fifth pereopod similar to fourth, slightly shorter.

Dorsal surface of pleon smooth, with scattered pits; abdominal segments with short setae present on caudal margins.

Telson with posterolateral spines, dense short setae present in posterior third. Posterior margins setose. Uropodal protopod with distal spine on mesial lobe. Exopod of uropod with transverse row of posteriorly directed diminutive spines ending in one more prominent spine, posteriorly directed on outer margin of mesial lobe. Terminal half of exopod with small tubercles and short hairs, slightly corrugated. Endopod of uropod smooth. Short scattered hairs present on posterior third of dorsal exopod. Postrolateral spine on outer margin present. Second spine on medial dorsal surface present, directed posteriorly.

Description of allotype female

(Fig. 6). Chela of first pereopods equal, 2.5 times as long as broad (24.5 mm and 9 mm respectively). Mesial margin of palm slightly elevated, forming slender serrated ridge with row of 9 small granular teeth. Cutting edge of dactylus with 8-9 rather small granular teeth. Cutting edge of fixed finger with 8-9 small granules. Small scattered short setae visible along ventral cutting edge of chelae, more dense and long in ventral posterior area. Tips of fingers slightly crossing when fingers clasp, not gaping. Cervical groove distinct, non-setose. Pleon just slightly narrower than cephalothorax (widths 12 mm and 12.5 mm respectively). Same colour pattern as in males, less intense.

Size. The biggest male examined has a carapace length of 48.7 mm, and a total length of 109 mm (n = 4),the holotype male has a total length of 92,8 mm the other males have a total length of 73mm and 96 mm; the female has a carapace length of 31.8 mm and a total length of 73 mm (n = 1).

Colour. The living animals (Fig. 1A, B) are coloured as follows. Male: Chelae dark blue with white margins and white patch. Anterior part usually dark blue. Corneous tooth on tip of fingers orange. Cephalothorax greenish black, with small slightly darker spots laterally, fading ventrally to grey-green. Pink to pinkish red patch on dorsolateral side of the carapace between rostral carinae and cervical grove. Segments of pleon with pinkish red band anteriorly becoming black in posterior part. Lateral pleura slightly lighter becoming greyish green. Walking legs blue to dark bluish grey. Distal margin of tail-fan creamy orange to orange. Females: usually greyish green to bluish grey with bluish chelae and a white margin.

Molecular phylogenetic results.

Cherax warsamsonicus sp. n. clusters with two sequences retrieved from GenBank as Cherax pulcher and the entire cluster forms a well-supported clade with Cherax misolicus (16S only, Fig. 7C). The C. ' pulcher ' sequences from GenBank almost certainly belong to Cherax warsamsonicus sp. n., as the included verified sequence of Cherax pulcher from a topotypical specimen is shown to be quite distinct and one of the two GenBank derived sequences is identical to the Cherax warsamsonicus sequence generated in this study. Cherax warsamsonicus sp. n. is well isolated from Cherax misolicus with a sequence divergence (p-distance, 16S) of 1.9-2.1 %, respectively, supporting the morphology-based description of Cherax warsamsonicus as a new species.

Deposition of types.

The holotype (MZB Cru 4529), allotype (MZB Cru 4530) and paratypes (MZB Cru 4531) are deposited at the Museum Zoologicum Bogoriense (= Bidang Zoologi) Reseach Centre for Biology (=Pusat Penelitian Biologi), Indonesian Institute of Sciences (= LIPI), Jalan Raya Jakarta-Bogor Km 46 Cibinong 16911, Indonesia.

Systematic position.

Holthuis (1949) in his publication on the New Guinea Cherax considered species should be placed into two groups. One with the rostral and median carinae absent or weakly developed and referred to as the Cherax group following the characteristics of the type species, Cherax preissii (Erichson) from southwest Australia. The other group contains species that have the rostral and sometimes the median carina well developed and referred to as the Astaconephrops group with Nobili’s (1899) Astaconephrops albertisii as the type. Newly described species have been placed into one or the other of the two subgenera ( Lukhaup and Pekny 2006; Lukhaup and Pekny 2008; Lukhaup and Herbert 2008; Lukhaup 2015, Lukhaup et al. 2015; Patoka, Blaha and Kouba 2015). Munasinghe et al. (2004a, b), Austin (1996); and Austin et al. (1996) however, identified three geographically-based lineages within Cherax based on mo lecular genetics and phylogenetic studies. These consist of a southwestern group, an eastern group and a northern group. Support for the latter group however was based on only very limited sampling (e.g. single samples of Cherax quadricarinatus , Cherax rhynchotus and Cherax peknyi in Munasinghe et al. study). Munasinghe et al. (2004b) indicate that the division of Cherax into two subgenera, as conceived by Holthuis and subsequent authors dealing with New Guinea crayfish has to be reconsidered. Based on Munasinghe et al. (2004), Austin (1996), and Austin et al. (1996a). Cherax warsamsonicus sp. n. belongs to the northern species group lineage consisting of 22 species:

Cherax albertisii (Nobili, 1899)

Cherax boesemani Lukhaup & Pekny, 2008

Cherax boschmai Holthuis, 1949

Cherax buitendijkae Holthuis, 1949

Cherax communis Holthuis, 1949

Cherax divergens Holthuis, 1950

Cherax gherardii Patoka, Bláha & Kouba, 2015

Cherax holthuisi Lukhaup & Pekny, 2006

Cherax lorentzi aruanus (Roux, 1911)

Cherax lorentzi lorentzi (Roux, 1911)

Cherax longipes Holthuis, 1949

Cherax misolicus Holthuis, 1949

Cherax murido Holthuis, 1949

Cherax monticola Holthuis, 1950

Cherax minor Holthuis, 1996

Cherax peknyi Lukhaup & Herbert, 2008

Cherax pallidus Holthuis, 1949

Cherax papuanus Holthuis, 1949

Cherax paniaicus Holthuis, 1949

Cherax pulcher Lukhaup, 2015

Cherax solus Holthuis, 1949

Cherax snowden Lukhaup, Panteleit & Schrimpf, 2015

In comparison to all species of the northern group the new species, Cherax warsamsonicus , is most similar to Cherax misolicus , a species that is endemic to Misool Island, one of four major islands in the Raja Ampat Islands in West Papua, Indonesia.

Cherax warsamsonicus sp. n. differs from Cherax misolicus in the following characters: shape of the chelae, (Fig. 8C, D), shape of the rostrum, the presence of setae on the rostrum and in colouration. Cherax misolicus has two rostral teeth on each margin of the rostrum while Cherax warsamsonicus sp. n. bears 3-4 prominent teeth on each margin. The rostrum of Cherax misolicus is rather straight, triangular shaped, while the rostrum of Cherax warsamonicus sp. n. is clearly bent outwards at middle part (Fig. 8A, B). Cherax warsamsonicus sp. n. has one prominent corneous spine and three tubercles present at middle part behind cervical groove on lateral sides of carapace while Cherax misolicus has 6-7 small tubercles present there. Cherax warsamsonicus sp. n. usually has bluish or dark blue chelae with a white coloured lateral margin and a white patch. Body colour is greenish grey with some pink or red patches on the dorsal carapace right behind the rostral carinae. Pleon is greenish grey with a red to pink pattern dorsally. Legs are usually blue, grey blue or grey. Cherax misolicus has light blue chelae, the body is olive green with orange bluish legs and a dark blue pleon with orange on the lateral pleon.

Cherax warsamsonicus sp. n. is endemic in the Warsamson River and Warsamson tributaries in West Papua while Cherax misolicus is endemic in creeks and rivers of Misool Island.

Etymology.

Cherax warsamsonicus sp. n. is named after the Warsamson River in West Papua where it seems to be endemic (Fig. 9).

Ecology.

Known only from the Warsamson River and its tributaries, South Sorong Regency in the central part of the Kepala Burung (Vogelkop) peninsula. The creeks from where these crayfish have been collected are shallow (20-60 cm) with a moderate flow, the water is clear, and have a pH of approximately 6.5. In most of the parts no water plants are present. The substrate of the creek is gravel or sand and soil mostly covered with silt and detritus, stones and larger rocks (Fig. 10). Crayfish hide in short borrows in the riverbank, under lager rocks or in detritus that gathers in slower flowing parts of the creek or river. To improve the knowledge of the distribution of the species more field trips will be necessary.

Common name.

The common name of the new species in the pet trade is Cherax "irian jaya", Cherax "pink coral", and sometimes it is sold also as Cherax pulcher . Therefore we propose the name Warsamson River Crayfish as a common name for the new species.