Cherax bomberai n. sp.

Figures 10–13.

Material examined. Holotype: male (MZB Cru), under rocks, wood, and in debris along banks of an unnamed tributary of the Otauar River drainage in the northeastern part of Fakfak Regency, West Papua, Indonesia. Coll. local people, November 2024. Crayfish were sent to us by KKCrayfish Farm in Jakarta. Allotype: female (MZB Cru), same data as holotype. Paratypes: one male (MZB Cru); one male and one female (ZMB 34711).

Diagnosis. Carapace surface smooth with numerous tiny tubercles posterior to cervical groove on lateral carapace. Eyes large, cornea globular, darkly pigmented. Rostrum lanceolate in shape with excavated margins. Rostral margins with two prominent teeth. Rostral carinae prominent. Postorbital ridges prominent with one acute tubercle at anterior terminus. Prominent uncalcified patch on lateral margin of chelae of adult male white, translucent. Carapace dark blue with orange and greenish stains on the anterior carapace. Chelipeds blue and white with white joints. Fingers with hooked tips. Other walking legs light blue to dark blue. Pleon dark blue with light greenish-blue and creamy transverse bands. Lateral pleura becoming lighter blue-green.

Description of male holotype (Figures 10–12). Body and eyes pigmented (Figure 10). Eyes large, cornea globular, darkly pigmented, nearly as long as eyestalk; as broad as eyestalk. Body subovate, slightly compressed laterally. Pleon narrower than cephalothorax (width 23.3 mm and 25.6 mm, respectively). Rostrum (Figure 12C) broad in shape, reaching middle of first antennular peduncle and about 2.6 times as long as wide (width 5.6 mm at base, length 14.5 mm). Margins slightly elevated continuing in rostral carinae on carapace, almost straight in basal part. Acumen with anteriorly orientated spine. Rostral margins with two spines on each side on anterior third of rostrum. Row of dense hairs present on anterior third of rostrum. Rostrum surface pitted with some short, tiny hairs present. Rostral carinae extending as slight elevations posteriorly on carapace, terminating at half of postorbital ridges. Postorbital ridges well developed, terminating in spiniform tubercle anteriorly, fading at half of rostro-cervical part of the carapace posteriorly. Surface between rostral carinae heavily pitted. Postorbital ridges about 1/3 of CL. Cervical and branchiocardiac grooves distinct, not setose; three well-developed spines present at middle part behind cervical groove on lateral sides of one side of carapace, and three well-developed and two smaller ones on the other side. Carapace (58.4 mm) surface smooth; numerous granules posterior to cervical groove on lateral carapace present. Anterior margin strongly produced; rounded upper margin directed inward. Areola smooth, pitted; length 17.9 mm; narrowest width, 9.6 mm. Length of areola 30.6% of total length of carapace (58.4 mm). Scaphocerite, broadest at posterior third, convex in distal part, becoming narrower in basal part; thickened lateral margin terminating in corneous spine, slightly overreaching ultimate segment of antennular peduncle. Left scaphocerite 17.3 mm long and 5.9 mm wide; proximal margins setose. Antennulae and antennae typical for genus. Antennae slightly longer than body. Antennal protopodite smooth, without spine, with row of hairs on inner margin; basicerite with one lateral and one ventral spine. Mouthparts typical for genus. Epistome with subcordiform cephalic lobe anteriorly bearing lanceolate cephalomedian projection constricted at base. Lateral margins of lobe not thickened; each lateral margin with a group of 4–5 and 8–10 small tubercles separated by a smooth region. Central part smooth, not pitted, excavate. First pereopods (Figure 12A,B) subequal in form, subequal in size, right chela slightly gaping, left chela not gaping. Left chelae probably regrown. Right cheliped 49.0 mm long, 10.8 mm high, and 20.7 mm wide. Left chelae 51.9 mm long and 9.6 mm high, 19.4 mm wide, strongly compressed. Fingers shorter than palm (right dactylus 19.4 mm long). Dactylus broad at base (8.2 mm), tapering slightly toward tip. Tip with sharp, corneous, hooked tooth pointing outwards at an angle of 45 ◦. Cutting edge of dactyl with continuous row of 9–10 small granular teeth and one larger granule at mid-length. Ventral and dorsal surface of movable finger smooth with scattered punctuation. Ventral posterior third of cutting edge with dense setae reaching from base to large granule. Fixed finger smooth, scattered punctuation, triangular, merging gradually into palm, ending in sharp, corneous, hooked tooth, parallel to x-axis of finger. Tips of fingers slightly cross when fingers clasp. Upper surface of palm practically smooth, slightly pitted. Fixed finger broader than dactyl at base (8.8 mm). Scattered, short setae present in posterior ventral part of fixed finger, reaching from palm to about one-third of cutting edge. Cutting edge of fixed finger with row of rather small granular teeth at posterior half and one slightly larger at about mid-length.

Outer lateral margin of chelae smooth with white, translucent patch covering about half of lateral margin. Row of 11–12 slightly elevated mesial propodal granules at dorsolateral margin. Dorsolateral margins slightly elevated in posterior two-thirds. Dorsal surface of carpus (16.3 mm) smooth, with excavation in middle part and with two well-developed mesial carpal spines; mesiolateral margin setose. Ventral carpal surface margins slightly elevated and with fovea; inner margin with well-developed ventral carpal spine and a prominent ventromesial carpal spine oriented at an angle of approximately 45 ◦. Merus (29.8 mm) laterally depressed in basal part; surface smooth; prominent dorsal meral spine present. Inner ventrolateral margin smooth; four ventral meral spines present: one at first third, one at mid-length, other at tip of anterior part, and fourth on distal ventrolateral inner margin. Ischium (15.1 mm) smooth with three small spines at ventrolateral inner margin.

Second pereopods reaching anteriorly to approximately mid-length of scaphocerite. Propodus (12.1 mm) and dactylus (6.6 mm) slightly longer than fixed finger (5.3 mm), of same height. Few scattered, short setae present on dactyl and fixed finger. Cutting edge of dactyl and propodus with row of dense, short setae. Carpus (9.5 mm), smooth, slightly pitted. Merus 16.7 mm. Ischium (8.1 mm) about half as long as merus.

Third pereopods overreaching second pereopods to mid-length of carpus. Fingers shorter than palm. Fourth pereopods reaching distal margin of scaphocerite. Dactylus (5.5 mm) with corneous tip; short setae present. Propodus (14.8 mm) about three times as long as dactylus, somewhat flattened, carrying many stiff setae anterior part. Carpus (13.8 mm) about 2.5 times as long as dactylus. Merus 19.8 mm. Fifth pereopods similar to fourth, slightly shorter. Dorsal surface of pleon smooth, with scattered pits; abdominal segments (1–5) with short setae present on caudal margins of segment. Pleon length 69.1 mm. Telson with posterolateral spines; dense short setae present in posterior third; posterior margins setose. Uropodal protopod with two distal spines 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 spines and short hairs, slightly corrugated. Endopod of uropod smooth. Short, scattered hairs present on posterior third of dorsal exopod. Posterolateral spine on outer margin present. Second spine on medial dorsal surface present, directed posteriorly. Total length 127.5 mm.

Description of female allotype (Figure 13). Chela of first pereopods equal, 2.9 times as long as broad (38.6 mm and 13.3 mm, respectively). Mesial margin of palm slightly elevated, forming slender serrated ridge with row of 17–18 small granular teeth. Cutting edge of dactylus with 12 rather small granular teeth, 1 slightly bigger. Cutting edge of fixed finger with 10 granules. Small, scattered, short setae visible along ventral cutting edges of chelae, denser and longer in ventral posterior area. Tips of fingers slightly cross when fingers clasp, slightly gaping. No soft patch present. Pleon as broad as cephalothorax (width 25.1 mm and 25 mm, respectively). Rostrum broad in shape, reaching the middle of first antennular peduncle and about 2.5 times as long as wide (width 6.7 mm at base, length 15.6 mm). Margins slightly elevated, continuing in rostral carinae on carapace, almost straight in basal part, distal third, pointing upwards at an angle of approximately 45 ◦. Acumen with anteriorly orientated spine. Few scattered hairs present on anterior third of rostrum. Rostral carinae extending as slight elevations posteriorly on carapace, terminating at half of postorbital ridges. Postorbital ridges well developed, terminating in spiniform tubercle anteriorly, fading at half of occipital carapace length, posteriorly. Postorbital ridges about 1/4 of CL. Cervical and branchiocardiac grooves distinct, not setose; four well-developed spines present at middle part behind cervical groove on lateral sides of carapace. Carapace surface smooth; numerous tiny granules posterior to cervical groove on lateral carapace present. Anterior margin strongly produced; rounded upper margin directed inward. Areola smooth, pitted; length 18.1 mm; narrowest width 10.7 mm. Length of areola 29.9% of total length of carapace (60.6 mm). Pleon length 74.5 mm. Same color pattern as in males. Total length 135.1 mm.

Size. The variation in size in the studied sample of C. bomberai n. sp. is given in Table 2, which also provides comparisons with all other newly described species.

Color. The living animals (Figure 10A,B) are colored as follows. Individuals of Cherax bomberai n. sp. usually have blue and white chelipeds with white joints. Prominent uncalcified patch on lateral margin of chelae of adult male, white, translucent. Carapace dark blue with orange and greenish stains on the anterior carapace. Fingers with hooked orange tips. Other walking legs light blue to dark blue. Pleon dark blue with light greenish-blue and creamy transverse bands. Lateral pleura becoming lighter blue-green. Females: same color as males with smaller chelae. Females do not show the creamy white soft patch.

Molecular phylogenetic results. Cherax bomberai n. sp. forms a highly supported, distinct clade that is the sister species of C. arguni n. sp. with high support; both species are, in turn, sister to a moderately supported clade comprising C. kaimana n. sp. and C. farhadii n. sp. (Figure 5). The clade comprising these four species is highly supported and very distinct; it is sister group to a clade comprising ten species, including, e.g., C. veritas n. sp. and C. pulcher, but this relationship is weakly supported. Cherax bomberai n. sp. is well isolated from C. arguni n. sp. and C. kaimana n. sp. / C. farhadii n. sp., with a sequence divergence (p-distance) of 1.7–1.9% (16S)/7.8% (COI) and 2.5–3.6%/12.0% (COI; C. kaimana n. sp. only), respectively, supporting the morphology-based description of C. bomberai as a new species.

Systematic position. Cherax bomberai n. sp. belongs to the northern species group lineage, now consisting of 35 species (please see the respective section for C. nigli n. sp. below for details.)

Systematic remarks. In comparison to all species of the northern group, the new species, Cherax bomberai n. sp., is morphologically and genetically most similar to C. arguni n. sp., to C. farhadii n. sp., and to C. kaimana n. sp. Cherax bomberai n. sp. may be easily distinguished from these three species by the coloration and pattern of live individuals, by the shape of the chelae, by the shape of the rostrum, and by DNA barcoding (please see the respective section for C. arguni n. sp. above for details (Figures 5–8)).

Ecology. Crayfish hide under rocks, wood, and among roots and in debris along banks of an unnamed tributary of the Otauar River drainage in the northeastern part of the Fakfak Regency, West Papua, Indonesia. To improve the knowledge of the distribution of this species, more field surveys will be necessary.

Distribution (Figure 9). Cherax bomberai n. sp. has so far only been found in a tributary of the Otauar River drainage in the northeastern part of the Fakfak Regency. It likely occurs at least throughout the entire catchment.

Common name. As the common name for this crayfish, we propose the Devil Crayfish, as it is already available under this name in the pet trade.

Etymology. The specific name derives from the origin (occurrence) of this population on the Bomberai Peninsula. It is proposed as a noun in apposition.