Turcinoemacheilus christofferi, Jouladeh-Roudbar, Vatandoust, Doadrio & Ghanav, 2023

Jouladeh-Roudbar, Arash, Vatandoust, Saber, Doadrio, Ignacio & Ghanavi, Hamid Reza, 2023, Integrative Taxonomy of Turcinoemacheilus Bănărescu & Nalbant, 1964 in West Asia with the Description of Three New Species (Teleostei: Nemacheilidae), Diversity 15 (1222), pp. 1-25 : 12-15

3.2.2. Turcinoemacheilus christofferi , New Species

( Figures 8 and 9 )

Holotype. BIAUBM 4-H, 1, 54.2 mm SL; Iran: Lorestan prov., Gholiyan River, tributary of Bakhtiyari River, Karun drainage, 33.07499, 49.64562 .

Paratypes. FSJF 4122 ( AJRPC-DNA 1713), 1, 41.5 mm SL; same data as holotype .

Diagnosis. Turcinoemacheilus christofferi is distinguished from any of the species of the T. kosswigi group ( T. ekmekciae , T. kosswigi , T. minimus , T. moghbeli , T. saadii , Turcinoemacheilus sp. ) by the anus situated behind the middle, between the pelvic and anal origins (vs. front middle). Turcinoemacheilus christofferi is similar to T. bahaii and T. hafezi but can be distinguished by a complete lateral line with more than 70 pores, reaching to the anterior part of caudal fin (vs. an incomplete lateral line, reaching to the anterior part of the dorsal fin, with less than 35 pores).

Description. See Figures 8 and 9 for general appearance and Table 4 for morphometric data. Small, slender, and oval-bodied species with short head. Body deepest at tip of pelvic fin, depth slightly decreasing towards caudal-fin base. Small hump at nape. Body almost equally wide until dorsal-fin origin. Section of head triangle, flattened on ventral surface. Caudal peduncle compressed laterally, 1.6–1.8 (mean 1.7) times longer than deep. Pelvic axillary lobe oval, its tip attached to body. Pelvic-fin origin distinctly in front of dorsal-fin origin. Pectoral fin tip reaching approximately 40–55% of the distance from pectoral-fin origin to pelvic-fin origin. Pelvic-fin tip not reaching anus. Distance from anus to anal-fin origin 2.6–2.9 times the distance from pelvic-fin to anal-fin origins. Anal-fin origin behind vertical of tip of dorsal fin when adpressed to body. Anal fin not reaching to middle of caudal peduncle. No adipose crest on caudal peduncle. An indentation in front of dorsal-fin origin. Margin of dorsal fin straight. Caudal fin forked or deeply emarginate. Largest known specimen 54 mm SL.

One central and one lateral pore on each side of supratemporal canal, 6–8 pores in anterior infraorbital canal, 3–4 pores in posterior infraorbital canal, 10 pores in the supraorbital canal, and 5–6 pores in mandibular canal. No suborbital flap or groove in male. Dorsal fin with 7½–8½ branched rays. Anal-fin with 5½ branched rays. Caudal fin with 8+8 or 8+7 branched rays. Pectoral fin 9 and pelvic-fin 6 branched rays. Body without scales. Lateral line complete; 72–74 pores reach base of caudal fin. Anterior nostril opening at end of a pointed flap-like tube. Posterior nostril oval, posterior tip of anterior nostril not or just overlapping posterior nostril when folded backwards. Mouth small, slightly arched. Lips moderately thick. A median interruption in lower lip. Upper lip without median incision. Processus dentiformis small and blunt. No median notch in lower jaw. Barbels: short, inner, and outer rostral barbel not reaching base of maxillary rostral barbel. Maxillary barbel reaching vertical of pupil. No external sexual dimorphism observed.

Coloration. White or cream background in life and ethanol preserved. A row of large irregular, brown, and longitudinally elongated blotches and saddles along lateral midline, often fused into a prominent irregular lateral stripe. Pattern on flank and back more or less faded in anterior part of body, possessing a plain brown on back, darker on lateral midlines. Large lateral blotches behind dorsal fin, connected to lateral blotches along whole body. A semilunar-shaped black or dark brown bar at caudal-fin base. A whitish or triangle-shaped patch in front of bar on upper and lower caudal peduncle. Cheeks dark olive or brown; ventral surface of head white or cream; head above cheeks pale dark brown. Operculum golden brown. Pectoral fin pale brown with elongated black spots on rays; pelvic fins yellowish; anal-fin hyaline; caudal and dorsal fins olive to dark brown. Caudal fins hyaline, with elongated spots on rays, forming two dark vertical rows, one approximately in middle of ray length and one on distal part. Dorsal fin rays with melanophores extending from approximately middle of ray length to distal margin.

Etymology. The species has been named in honor of Christoffer Fägerström (Lund University, Sweden) in recognition of his invaluable contributions to the photography and comprehensive documentation of type specimens of a variety of taxa, including insects, fishes, and other organisms. Most pictures of the type materials in this study have been very kindly contributed by him. A noun in the genitive case.

Distribution. The species appears to have an extremely limited distribution. It is currently only known to exist in the Gholiyan River ( Figure 10 ), a headwater tributary of the Bakhtiyari River system of the Karun drainage.

Habitat. Turcinoemacheilus christofferi inhabits the fast-flowing parts of river, with a preference for high-gradient riffles and rapids. It is typically found in areas with clear, cold, and well-oxygenated water running over coarse substrata such as gravel, pebbles, and rocks. The species occurs among the interstitial spaces within loosely embedded gravel beds and avoids silt-bedded pools or slow currents. Several rainbow trout fish farms have been recently established around the type locality of this species. Unfortunately, a recent flood released many rainbow trout into the river. As a consequence, the population of this species in the Gholiyan River has significantly diminished.

Remark. Turcinoemacheilus christofferi is restricted to the headwaters of the Bakhtiyari River system. Despite extensive survey efforts encompassing more than 30 sampling stations across the river’s headwaters in different seasons, no additional specimens have been collected. The species’ limited range is likely a result of competitive exclusion by the larger and more widespread Oxynoemacheilus euphraticus , which dominates optimal habitats. Further field studies and extensive sampling of the region are needed to elucidate T. christofferi ’s distribution range and biology.

Figures

Figure 8. Turcinoemacheilus christofferi, holotype, BIAUBM 4-H, 54 mm SL, and paratype, AJRPC 1713, 41 mm SL; Gholiyan River.

Figure 9. Turcinoemacheilus christofferi, from top: holotype, 54 mm SL; paratype, 41 mm SL; Gholiyan River.

Figure 10. Type locality of Turcinoemacheilus christofferi; Gholiyan River, Iran.