Cherax farhadii n. sp. Figures 21–24. Material examined. Holotype: male (MZB Cru), under rocks, wood, and among roots and in debris along banks of a nameless tributary unnamed creek in the Teluk Bintuni Regency, West Papua, Indonesia. Coll. local people, May 2019. Crayfish were sent to Aquarium Dietzenbach by Maju Aquarium, Jakarta. Allotype: female (MZB Cru), same data as holotype. Paratypes: two males and one female (MZB Cru); three males and one female (ZMB 34712); same data as holotype. Diagnosis. Carapace surface smooth. Eyes large, pigmented. Cornea slightly broader than eyestalk. Rostrum lanceolate in shape with excavated margins. Rostral margins with two prominent teeth on one side and three on the other. 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. Propodal cutting edge with row of small granules and one larger tubercle. Chelipeds blue and white with white joints. Fingers with hooked tips. Other walking legs light blue to dark blue. Pleon dark blue with creamy transverse bands. Lateral pleura becomes lighter green or blue to creamy. Some animals with pink lateral dot on five segments, others with yellowish to greenish dot. Several animals, usually the adult ones, show a dent on the epigastric region between the rostral carinae from the rostrum end to the end of the carinae. This was not observed by other Cherax described from Papua. Description of male holotype (Figures 21–23). Body and eyes pigmented (Figure 21). Eyes not reduced. Cornea slightly broader than eyestalk. Body subovate, slightly compressed laterally. Pleon narrower than cephalothorax (width 22.7 mm and 25.9 mm, respectively). Rostrum (Figure 23C) broad in shape, overreaching first antennular peduncle and about 2.3 times as long as wide (width 6.9 mm at base, length 15.9 mm). Margins elevated, continuing in rostral carinae on carapace, almost straight in basal part. Acumen with anteriorly orientated spine. Rostral margins with two spines on one side and three on the other side on anterior third of rostrum. Row of dense 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. Surface between rostral carinae pitted. Postorbital ridges about 1/4 of CL. Dent on dorsal carapace between rostral carinae from rostrum end to end of carinae present. Cervical and branchiocardiac grooves distinct, not setose; three spines present at middle part behind cervical groove on lateral sides of carapace on one side and four on the other. Carapace (59.9 mm) surface smooth; anterior margin strongly produced; rounded upper margin directed inward. Areola smooth, pitted. Length, 17.5 mm; narrowest width, 10.8 mm. Length of areola 29.2% of total length of carapace (59.9 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 10.3 mm long and 5.2 mm wide; proximal margins setose. Antennulae and antennae typical for genus. Antennae 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 rounded lanceolate cephalomedian projection constricted at base. Lateral margins of lobe not thickened; each lateral margin with group of 5–6 small tubercles separated by smooth region. Central part smooth, not pitted, excavate. First pereopods (Figure 23A,B) equal in form, chela slightly gaping. Left cheliped 59.6 mm long, 12.6 mm high, and 26.5 mm wide. Right chelae 50.8 mm long and 12 mm high, 19.1 mm wide, strongly compressed. Fingers shorter than palm (right dactylus 18.4 mm long). Dactylus broad at base (7.0 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 6–7 small granular teeth and 1 larger granule. Ventral and dorsal surface of movable finger smooth with scattered punctuation. Ventral cutting edge with few short, scattered setae on base. 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, more densely pitted at margins. Fixed finger broader than dactyl at base (8.5 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 and one slightly bigger one. Outer lateral margin of chelae smooth with white, translucent patch covering about two-thirds of lateral margin. Row of 11–12 small slightly elevated mesial propodal granules. Dorsolateral margins slightly elevated in posterior half. Dorsal surface of carpus (17.7 mm) smooth, with slight excavation in middle part and with two well-developed mesial carpal spines. Ventral carpal surface margins slightly elevated, setose, 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 (27.78 mm) laterally depressed in basal part; surface smooth; prominent dorsal meral spine present at anterior third; inner ventrolateral margin smooth; four ventral meral spines present: one at first third, one at mid-length, another at tip of anterior part, and fourth on distal ventrolateral inner margin. Ischium (14.7 mm) smooth with 1 small spine and 3–4 granules at ventrolateral inner margin. Second pereopods reaching anteriorly to approximately anterior third of scaphocerite. Propodus (11.9 mm) and dactylus (6.5 mm) slightly longer than fixed finger (6.1 mm), of same height. Few scattered, short setae present on dactyl and fixed finger. Cutting edge of dactylus and propodus with row of dense, short setae. Carpus (14.6 mm), smooth, slightly pitted. Merus 17.5 mm. Ischium (9.1 mm) about half as long as merus. Third pereopods overreaching second pereopods to mid-length of carpus. Fingers shorter than palm. Dactylus (7.1 mm) with corneous tip; short, scattered hairs present in posteriour half. Propodus (15.4 mm) about two times as long as dactylus, somewhat flattened. Carpus (14.9 mm) about twice as long as dactylus. Merus 15.6 mm. Fourth pereopods reaching distal margin of scaphocerite. Dactylus (3.9 mm) with corneous tip. Short, scattered setae present. Propodus (11.9 mm) about three times as long as dactylus, somewhat flattened, carrying scattered stiff setae on lower margin. Carpus (8.1 mm) about twice as long as dactylus. Merus 16.3 mm. Fifth pereopods similar to fourth, shorter. Dorsal surface of pleon smooth, pitted; abdominal segments (1–5) with short creamy colored setae present on caudal margins of segment. Pleon length 64.4 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 124.3 mm. Description of female allotype (Figure 24). Chela of first pereopods equal, 2.9 times as long as broad (29.1 mm and 9.8 mm, respectively). Mesial margin of palm slightly elevated, forming slender serrated ridge with row of 9–10 small granular teeth. Cutting edge of dactylus with 6–9 rather small granular teeth, 1 slightly bigger. Cutting edge of fixed finger with 7–8 small granules, 1 slightly bigger. 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, not gaping. No soft patch present. Pleon narrower than cephalothorax (width 21.7 mm and 22.4 mm, respectively). Rostrum broad in shape, reaching middle of first antennular peduncle and about 2.1 times as long as wide (width 6.3 mm at base, length 13.8 mm); margins 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. Short, dense 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. Slight dent on epigastric region between rostral carinae from rostrum end to end of carinae. Postorbital ridges about 1/4 of CL. Cervical and branchiocardiac grooves distinct, short, scattered hairs present at lateral mid part; three small spines present on one side and four on the other at middle part behind cervical groove on lateral sides of carapace. Carapace surface smooth; anterior margin strongly produced; rounded upper margin directed inward. Areola smooth, pitted; length, 15.2 mm; narrowest width, 9.3 mm. Length of areola 30.2% of total length of carapace (50.3 mm). Same color pattern as in males. Total length 112.9 mm. Size. The variation in size in the studied sample of C. farhadii n. sp. is given in Table 2, which also provides comparisons with all other newly described species. Color. The living animals (Figure 21A–C) are colored as follows. Individuals of Cherax farhadii n. sp. usually have blue chelipeds with white joints. Uncalcified patch on lateral margin of chelae, white, translucent. Fingers with hooked orange tips. Carapace dark blue or greenish-blue, becoming lighter laterally. Numerous creamy to white small spots on lateral and dorsal carapace. Walking legs light blue to dark blue. Pleon dark blue with creamy transverse bands. Lateral pleura becoming lighter green or blue to creamy. Some animals with a pink lateral dot on five segments, others with yellowish to greenish dot. Females: same color as males with smaller chelae. Females do not show the creamy white soft patch. Molecular phylogenetic results. Cherax farhadii n. sp. forms a highly supported, distinct clade that is a sister species to C. kaimana n. sp. with mediocre support; both species are, in turn, sister to a highly supported clade comprising C. arguni n. sp. and C. bomberai 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 farhadii n. sp. is well isolated from C. kaimana n. sp. and C. arguni n. sp. / C. bomberai n. sp., with a sequence divergence (p-distance, 16S) of 2.3% and 3.2–3.8%, respectively, supporting the morphology-based description of C. farhadii as a new species. Systematic position. C. farhadii 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 farhadii n. sp., is morphologically and genetically most similar to C. arguni n. sp., to C. bomberai n. sp., and to C. kaimana n. sp. Cherax farhadii 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. The habitat of this species is not known. The catchers are keeping the exact location a secret. Distribution (Figure 20). Bird’s Head Peninsula, Teluk Bintuni Regency. Common name. As the common name for this crayfish, we propose Red Cheek Crayfish, as it is already available under this name in the pet trade. Etymology. Cherax farhadii n. sp. is named after Farschad Farhadi, a freshwater invertebrate enthusiast and friend of the first author. With this work, the first author would like to thank him for all his years of support.

Published as part of Lukhaup, Christian, Eprilurahman, Rury & Rintelen, Thomas von, 2025, Seven New Species of Crayfish of the Genus Cherax (Crustacea, Decapoda, Parastacidae) from Western New Guinea, Indonesia, pp. 1-55 in arthropoda 3 (2) on pages 28-33, DOI: 10.3390/arthropoda3020010, http://zenodo.org/record/18484894