Eidinemacheilus, Segherloo, Iraj Hashemzadeh, Ghaedrahmati, Nabiallah & Freyhof, Jörg, 2016

Segherloo, Iraj Hashemzadeh, Ghaedrahmati, Nabiallah & Freyhof, Jörg, 2016, Eidinemacheilus, a new generic name for Noemacheilus smithi Greenwood (Teleostei; Nemacheilidae), Zootaxa 4147 (4), pp. 466-476 : 471-474

Eidinemacheilus , new genus

Fig. 2–4

Type species. Noemacheilus smithi Greenwood, 1976:129

Material examined. FSJF 3431, 1, 28 mm SL; FSJF 3541, 4 , 30–38 mm SL; Iran: Lorestan prov.: Natural welllike opening being the origin of the stream Kay-e-Ru flowing to Sirom River, near Baq-e-Levan oasis, 33°04'38''N 48°35'35''E; (GenBank accession numbers: KX429660 and KX461958 ).

Diagnosis. Eidinemacheilus is distinguished from all genera of nemacheilid loaches in the Middle East by having 7+7 branched caudal-fin rays (vs. 9+8, rarely 8+8), lacking eyes and pigmentation (vs. presence) and having a reduced set or no head canals (vs. all head canals complete or almost complete). In Eidinemacheilus , the supratemporal canal is absent, the infraorbital canal is reduced and present only at its posterior part with 2–3 pores, the supraorbital canal has 0–3 pores in its anterior part, close to the nares and only the preoperculo-mandibular canal is almost complete in one out of four individuals, reduced at its posterior part in the others.

Eidinemacheilus smithi was identified as a species in Paracobitis by Nalbant & Bianco (1998), from which it is, in addition to the already mentioned characters, distinguished by having smooth lips, covered by small papillae, without furrows (vs. with furrows). Eidinemacheilus is also distinguished from all species of Oxynoemacheilus and Seminemacheilus by the absence of an external sexual dimorphism (vs. longer pectoral fin, nuptial tubercles on fins, head and back in male). Eidinemacheilus is also distinguished from Seminemacheilus by having a small epural bone in the caudal skeleton (vs. absent). Eidinemacheilus is distinguished from Sasanidus by the presence of a dorsal adipose crest (vs. absence) and a deeply emarginate caudal fin (vs. slightly emarginate), and from Turcinoemacheilus by having the pelvic-fin origin clearly behind of a vertical of the dorsal-fin origin (vs. pelvic-fin origin in front of a vertical of the dorsal-fin origin) and the anus situated almost immediately in front of the anal-fin origin (vs. more than two eye diameters). Eidinemacheilus is distinguished from Paraschistura by having smooth lips, covered by small papillae, without furrows (vs. with furrows), very thick lips, overlapping the base of the maxillary barbel (vs. not overlapping), a very small epural bone, much narrower than the hypural bones 4–5 in the caudal skeleton (vs. about as wide as hypural bones 4–5) and the hemal processes of the second preural centrum being narrow at its proximal half and widening distally (vs. large and wide at its full length). Also, the lower lip in Eidinemacheilus is deeply interrupted in the middle and forms a small, backward pointed, mental lobe at each side of the interruption ( Fig. 4 ) (vs. mental lobe absent).

Etymology. The generic name is made out of the the name of the ranger protecting the locality “Eidi Heidari” and Nemacheilus , for loaches. Gender masculine.

Distribution. Eidinemacheilus smithi is known from a well-like spring in the proximity of the Bagh-e-Levan oasis in the Sezar River drainage. The Sezar is a headwater of the Dez River. The Dez is a tributary to the Karun and the Karun flows from the Iranian Zagros Mountains westwards into the lowermost Tigris.

Included species. Monotypic.

Discussion. The holotype of Eidinemacheilus smithi was illustrated by Greenwood (1976:131) and the species can be immediately identified by its body shape and the absence of the eye and pigments.

We were not able to obtain materials of the nemacheilid genera Afronemacheilus from Ethiopia and Iskandaria , Dzihunia and Troglocobitis from Central Asia. We compared Eidinemacheilus with these genera based on the data provided by Parin (1983), Prokofiev (2009) and Prokofiev (pers. comm). Eidinemacheilus is distinguished from these four genera by having 7+7 branched caudal-fin rays (vs. usually 8+ 8 in Afronemacheilus , 9+ 8 in Iskandaria , 9+ 8 in Dzihunia , 9+ 8 in Troglocobitis ), and reduced or absent head canals (vs. all head canals complete in all other genera). Eidinemacheilus is further distinguished from Afronemacheilus by having the pelvicfin origin behind a vertical of the dorsal-fin origin (vs. below), a small epural bone in the caudal skeleton (vs. absent) and a different shape of the hemal processes of the second preural centrum (narrow at its proximal half, widening distally vs. wide at its full length). Eidinemacheilus is further distinguished from Iskandaria by lacking the pelvic axillary lobe (vs. present), having a small epural bone, much narrower than the hypural bones 1–5 in the caudal skeleton (vs. about as wide as hypural bones 4–5) and the hemal processes of the second preural centrum is narrow at its proximal half and widening distally (vs. large and wide at its full length). Eidinemacheilus is further distinguished from Dzihunia by having simple lip structures (vs. lower lip with pillow-like elements interrupted by deep folds) and a smooth skin (vs. with small, spine-like epidermal tubercles).

Troglocobitis starostini is a subterranean nemacheilid loach endemic to Kugitangtau in Turkmenistan. Prokofiev (2009:889) wrote: “In the original description of N. smithi there is no information at all on the structure of the bony capsule of the swimming bladder and its presence ( Greenwood 1976). Obviously, this character was not investigated by Nalbant & Bianco (1998: 115); therefore, without reinvestigation of the type, it is not possible to conclude whether this species belongs to Paracobitis or to Troglocobitis ”. Troglocobitis lack a bony swimbladder capsule (vs. present in Eidinemacheilus ) and both share a shallow dorsal adipose crest ( Parin, 1983). Already Parin (1983) discussed the potential relationships of Troglocobitis with Paracobitis , as both genera have a dorsal adipose crest. As already stated in the introduction of our study, the presence or absence of a dorsal adipose crest is a character state widely found in nemacheilid loaches and is unsuited as a sole character to diagnose higher taxonomic groups as genera. Eidinemacheilus is distinguished from Troglocobitis by having a bony swim-bladder capsule (vs. lacking), 7+7 branched caudal-fin rays (vs. 9+8), and reduced or absent head canals (vs. all head canals complete). Also, the presence of a genus including only two troglomorphic species in two biogeographcally well separated regions as Turkmenistan in Central Asia and the Karun in Mesopotamia seems to be extremely unlikely.

Greenwood (1976:130) already stated that a new genus should not be described for N. smithi based on character states connected to the adaptation to the subterranean environment. Kottelat & Leisher (2012:242) already mentioned: “...as most other cave fishes, show more or less reduced or missing eyes, lateral line, pigmentation, squamation, fewer fin-rays, and more developed crests on caudal peduncle”. Indeed, we cannot exclude that all the character states being unique to Eidinemacheilus are connected to its adaptation to subterranean life. Therefore, we depend on molecular characters being the only set of characters independent from adaptations to to subterranean life.

There are few studies about the genera of nemacheilid loaches of the Middle East ( Bănărescu & Nalbant 1995; Prokofiev 2009) and there are also few studies presenting molecular data on nemacheilid loaches of that area (Esmaeili et al. 2014; Freyhof et al. 2014; Freyhof et al. 2015; Freyhof et al. 2016). The COI barcode sequences analysed here and the very limited species coverage of the species-rich family Nemacheilidae do not allow a phylogenetic conclusion to be made from the dataset presented in this study. The resolution of this mitochondrial marker is not sufficient to reliably resolve the relationships between the different genera studied, which is clearly reflected in the poor support of some inner nodes ( Fig 1). Therefore, we do not speculate on the relationships of the different genera of nemacheilid loaches included in this study, although the topology of the different groups in the tree might be an indication of their relationships . DNA barcode data from all known genera of nemacheilid loaches from Europe , the Middle East and Western India were brought together by Freyhof et al. (2016) and the same dataset is used in this study. Eidinemacheilus stands as a separate group not affined to any supported sub-clade included in our dataset ( Fig 1). The phylogenetic and molecular divergence data help us to identify Eidinemacheilus as a candidate taxon for a more comprehensive investigation, and aided with taxonomic sampling, putting the mitochondrial lineage of these fishes into a broader phylogenetic and biogeographic context. Taking all concerns into consideration, our data does not even place Eidinemacheilus close to one of the genera described from Europe , the Middle East or India, supporting the hypothesis that it represents a distinct genus of its own. However, we do not exclude that other, epigean, species of Eidinemacheilus might occur in Pakistan or India, where they might currently be identified as species of Schistura . As the identification of Eidinemacheilus is based on characters which might all be adaptations to subterranean life, the identification of potentially epigean species of Eidinemacheilus will be possible by the molecular characters made available though this study.

Figures

FIGURE 2. Eidinemacheilus smithi, FSJF 3431, 28 mm SL; Iran: Natural well-like opening being the origin of the stream Kay-e-Ru.

FIGURE 3. Eidinemacheilus smithi, FSJF 3541, 38 mm SL, 34 mm SL, 34 mm SL, 30 mm SL; Iran: Natural well-like opening being the origin of the stream Kay-e-Ru.

FIGURE 4. Eidinemacheilus smithi, FSJF 3541, 34 mm SL, Iran: Natural well-like opening being the origin of the stream Kaye-Ru.