Parapsilorhynchus alluriensis, Jadhav & Karuthapandi & Chandra & Jaiswal & Dinesh & Narahari, 2020

Jadhav, S. S., Karuthapandi, M., Chandra, Kailash, Jaiswal, Deepa, Dinesh, K. P. & Narahari, A., 2020, Parapsilorhynchus alluriensis, a new species of cyprinid fish (Teleostei: Cyprinidae) from the Eastern Ghats, of India, Zootaxa 4751 (3), pp. 563-574 : 564-572

Parapsilorhynchus alluriensis , sp. nov.

(Figure. 2)

Holotype. ZSI / FBRC /F/3015, 35.4 mm SL. India, Eastern Ghats, Andhra Pradesh State, Visakhapatnam District, Dharamattam stream, near Golugonda village , Alluri Forest , 17°42´47˝N; 82°28´42˝E, 210 m asl, S. S. Jadhav and M. Karuthapandi on 3 November 2018.

Paratypes. ZSI / FBRC /F/3016, 5, 21.7–34.1 mm SL; same data as holotype ; ZSI / WRC /F/5534, 4, 23.2–34.4 mm SL, same data as holotype .

Diagnosis. Parapsilorhynchus alluriensis , is distinguished from its congeners by a combination of the following characters: Body small, elongate, head depressed; a poorly-developed callous pad present behind lower lip; the pad not distinctly delimited posteriorly; head deep (depth at occiput 47.3–72.3% HL); body stout, deep (depth at dorsal fin origin 17.3–21.7 % SL); gape width 27.3–32.8% HL; inter-orbital space 33.9–43.2% HL; eyes visible in ventral view; lower lip rounded; mouth small, inferior and horizontal; mouth opening situated very close to anterior tip of snout; upper lip concealed by poorly-developed slightly fringed rostral fold; rostral fold with minute papillae; 3 simple pectoral-fin rays; 33–34 lateral-line scales.

Phylogenetic relationships. Parapsilorhynchus alluriensis is recovered as a member of the ‘ Parapsilorhynchus clade’ (Figure 6), with a sister - group relationship to P. prateri having a genetic divergence of 1.5 % on the mt COI gene (Table 3).

Description. Morphometric data of the holotype and nine paratypes are listed in Table 1. Body small, elongate, anteriorly cylindrical, posteriorly depressed, greatest depth at dorsal-fin origin; ventral surface flattened. Eyes prominent, lateral, visible in ventral aspect, situated in middle of length of head, their diameter less than inter-orbital space. Head depressed; snout prominent; moderately rounded in ventrally view, obtuse in lateral view. Mouth small, inferior, horizontal, situated on ventral surface; mouth opening close to tip of snout; upper lip concealed by poorlydeveloped slightly fringed rostral fold; minute papillae present on rostral fold. Lower lip finely papillated, rounded, with poorly-developed callous pad behind it, forming anterior free border of pad; lower lip studded with minute tubercles. Callous pad not distinctly delimited posteriorly ( Figure 4A ). Corner of mouth with a marginal groove, continuing anteriorly round outer margin of rostral fold. Rostral barbel short, thick, stumpy, not pointed distally; shorter than eye diameter, positioned anterolaterally.

TABLE 1 . Morphometric and meristic data of 10 specimens ( ZSI / FBRC /F/3015; ZSI / FBRC /F/3016; ZSI / WRC / F/5534) of Parapsilorhynchus alluriensis including holotype (values for the holotype are also stated separately in parentheses) .

Dorsal fin commencing slightly in advance of pelvic-fin base, with two simple and 7 branched rays, shorter than head length, its origin slightly nearer caudal-fin base than tip of snout; distal margin slightly concave. Pectoral fin with 3 simple and 11 branched rays, shorter than head length, not reaching pelvic-fin origin. Pelvic fin with two simple and 7 branched rays, shorter than pectoral, not reaching anus. Anal fin base short, with one simple and 5 branched rays, not reaching base of caudal fin; distal margin slightly concave. Anus positioned nearer anal-fin origin than pelvic-fin origin. Caudal fin forked with i, 17 - 18, i principal rays; upper and lower lobes equal in length. Lateral line complete with 33 - 34 scales. Scale rows between lateral line and dorsal fin 5, between lateral line and pelvic-fin origin 4. Predorsal scales 18 - 19, mostly embedded in skin. Scales arranged irregularly. Scales on chest and belly smaller than those on flank, embedded in skin.

TABLE 2. GenBank accession numbers, locations and voucher numbers for the mt COI gene sequences used in the study.

TABLE 3. Uncorrected pairwise genetic distance (%) for the species of Parapsilorhynchus and Garra used in the phylogenetic analysis.

Coloration. In 70% alcohol (Figure 2): head and body dull greyish brown dorsally, becoming lighter laterally, off - white ventrally. Flank with a black stripe along lateral - line scales. Black blotch at the base of caudal - fin. Pectoral, pelvic and anal fins hyaline. Dorsal fin hyaline with an oblique black bar near its free margin. Scales speckled with melanophores at their bases.

In life (Freshly dead) (Figure 3): Body dark grey, ventral surface uniformly cream white; head dorsally dark brown. Dorsal fin with a yellowish tinge and a distinct oblique black bar near its free margin. Along the lateral line, a broad black longitudinal band with a lighter band above and below it. A black vertical bar present on the caudal peduncle. Caudal fin dusky with vertical black bar at its base. Pectoral, pelvic and anal fins with light-yellow pigmentation on rays. Each body scale studded with melanophores.

Habitat. Parapsilorhynchus alluriensis inhabits cool, clear streams with riparian vegetation and a steep gradient. The substrate consisted mainly of stones, bedrock, some sand, boulders and gravels; water volume apparently much higher during the rainy season ( Figure 7 ). Co-occurring species are Rasbora daniconius Hamilton , Devario aequipinnatus McClelland and Garra mullya Sykes.

Etymology. Named after the Alluri Forest, Eastern Ghats, Visakhapatnam District, Andhra Pradesh State, India from where the type specimens were collected.

Distribution. Parapsilorhynchus alluriensis is at present known only from the type locality.

Comparative morphometrics. Parapsilorhynchus alluriensis can be distinguished from P. tentaculatus in having a smaller inter-orbital space (33.9–43.2% HL vs. 50.0), fewer lateral-line scales (33–34 vs. 36–39), having the eyes visible (vs. not visible) from ventral aspect, and a rounded (vs. bilobed) lower lip, ( Figure 4 ). Hora (1921) described P. discophorus based on a single specimen. However Hora later (1925) stated that an examination of large series of specimens convinced him that the two species were identical. However, Yazdani & Babu Rao (1977) considered P. discophorus as a valid species and remarked that the two differ from each other in the number of lateral - line scales (33-35 in P. discophorus and 36-39 in P. tentaculatus ), number of simple pectoral fin rays (2 vs. 3) and body proportions such as eye diameter (4.0-6.0 % in SL vs. 6.0-8.5) in relation to standard length. Nevertheless, Rema Devi & Menon (1995) justified Hora’s (1925) decision to synonymize P. discophorus with P. tentaculatus based mainly on the range of pectoral-fin ray counts and morphometric measurements. But they did not mentioned whether they examined specimens of P. discophorus . However, after examination of topotypic material, the present study also confirm P. discophorus and P. tentaculatus are distinct species in view of the distinct characters, two vs. three undivided pectoral-fin rays; 33 - 35 vs. 36 - 39 lateral - line scales; rounded vs. bilobed lower lip; eyes visible vs. not visible in ventral aspect; a distinct disc behind lower lip vs. merely thickened area without forming a distinct disc.

Parapsilorhynchus alluriensis and P. discophorus have the same number of lateral-line scales, the eyes distinctly visible from the ventral side and similar body coloration. However, P. alluriensis can be distinguished from P. discophorus in having more simple pectoral-fin rays (3 vs. 2), a narrower gape (27.3–32.8% HL vs 32.6–40.0), a poorly (vs. prominently) developed callous pad, not sharply (vs. distinctly) delimited posteriorly, and the absence of (vs. poorly developed) tubercles on the snout. The new species differs from P. elongatus in having a stout (vs. elongate) body, smaller inter-orbital space (33.9–43.2% HL vs. 60.2–66.6), and fewer lateral line scales (33–34 vs. 36). Parapsilorhynchus alluriensis differs from P. prateri in having fewer lateral line scales (33–34 vs. 42–47), smaller inter-orbital space (33.9–43.2% HL vs. 47.3–50.0), pectoral fin shorter than head length (vs. equal to head length), and a poorly (vs. well) developed callous pad behind the lower lip. The new species differs from P. odishaensis in having a greater eye diameter (28.4–44.1% HL vs. 18.7–28.6), smaller inter - orbital space (33.9–43.2% HL vs. 53.3–64.3), wider gape (27.3–32.8% HL vs. 23.5–28.6), absence (vs. presence) of tubercles on the snout, and having the pectoral-fin shorter than head length (vs. equal or longer than head length). Further, Parapsilorhynchus alluriensis can be distinguished from P. swaini in having smaller inter - orbital space (33.9–43.2% HL vs. 46.6–50.0),pectoral fin length shorter than head length (vs. longer than head length), a black bar on anal fin absent (vs. present), and a rounded unilobed (vs. bilobed) lower lip ( Figure 4 ).

The genus Parapsilorhynchus was first recognized by Hora (1921), who designated P. tentaculatus ( Annandale, 1919) as type species during the description of P. discophorus . Since then a total of four species have been added to this genus ( P. prateri in 1938, P. elongatus in 1994, P. odishaensis and P. swaini in 2017) bringing the total known species to seven including the new species described herein. The genus appears to be restricted to peninsular India ( Figure 1 ). P. tentaculatus was also reported from Satpura hills ( Hora, 1925), Bailadila range in Bastar (Hora, 1938) and from Eastern Ghats (Remadevi and Menon, 1995), but the identity of this species from these localities needs further confirmation since the species is known only from northern Western Ghats. Rao and Yazdani (1978) commented on the apparent evolution of the genera Parapsilorhynchus and Psilorhynchus based on their morphology and biogeography, concluding Psilorhynchus to be primitive in comparison to Parapsilorhynchus . The findings of Rao and Yazdani (1978) can only be substantiated with the availability of complete phylogeny of the group.

Discussion

Due to lack of genetic information for the phylogenetic analysis, the genus Parapsilorhynchus is considered as a member of Labeoninae (Cyprinidae) , which have been shown to have an unresolved phylogenetic relationship with the members of Labeonini and Garrini ( Yang et al., 2015; Betancur-R et al. 2017). Parapsilorhynchus was not included in the phylogeny of the cyprinid tribe Labeonini in the above studies, which made Yang et al. (2012) and Tan and Armbruster (2018) treat the genus ‘incertae sedis’. Patil et al. (2018), in their DNA barcode (mt COI) based delineation of freshwater fishes from the northern Western Ghats, included two species of Parapsilorhynchus ( P. tentaculatus and P. discophorus ) in their Cyprinidae gene tree and this data along with ours for another two species of Parapsilorhynchus establishes the phylogenetic ‘ Parapsilorhynchus clade’ position on the larger Cyprinidae tree. GenBank sequence JQ667561.1 for the species P. prateri is a case of misidentification as the specimen collected from Harda, Madhya Pradesh, but P. prateri has very restricted distribution in the northern Western Ghats. P. prateri is unique with large number of lateral-line scales (Figure 5). Nevertheless, we warrant more intensive sampling and multigene phylogenetic analysis to decipher the actual phylogenetic position of Parapsilorhynchus within the Cyprinidae or to reestablish the family Parapsilorhynchidae .

The occurrence of P. alluriensis in the Eastern Ghats reveals a wider distributional range of this highly specialized hill stream genus.

Figures

FIGURE 1. Distribution of the species of Parapsilorhynchus in Peninsular India

FIGURE 4. Ventral view of head: A. Parapsilorhynchus alluriensis (ZSI/FBRC/F/3015), holotype; B. P. discophorus (ZSI/ WRC/F/3360); C. P. odishaensis (ZSI-K/F/4626); D. P. tentaculatus (ZSI-K/F/9695/1); E. P. prateri (ZSI-K/F/12498/1); F. P. swaini (ZSI-K/F/5057).

FIGURE 7. Habitat at type locality of Parapsilorhynchus alluriensis