Glyptothorax alidaeii, Mousavi-Sabet & Eagderi & Vatandoust & Freyhof, 2021

Glyptothorax alidaeii , new species

( Fig. 7–10 View FIGURE 7 View FIGURE 8 View FIGURE 9 View FIGURE 10 )

Holotype. GUIC GTA-H, 128 mm SL; Iran: Lorestan prov.: Seimare River at Zirkhaki , 33.6880 47.0639. GoogleMaps

Paratypes. FSJF 4111 , 2 , 35–78 mm SL; IMNRF-UT- 1222, 4 , 27–42 mm SL; VMFC GTA-P, 2, 83– 99 mm SL; same data as holotype GoogleMaps .

Material used in molecular genetic analysis. IMNRF-UT-1222 ; same data as holotype (GenBank accession numbers: MZ959036 View Materials , MZ959037 View Materials ) GoogleMaps .

Diagnosis. Glyptothorax alidaeii is distinguished from its congeners in the Persian Gulf basin by a combination of characters, none unique to the species. It is distinguished from the other congeners in the Persian Gulf basin with the exception of G. steindachneri , by having a pointed and short head, HL 21–24% SL (vs. blunt and spade-shaped, 24–33).

Glyptothorax alidaeii is distinguished from G. silviae by having a less deeply forked caudal fin (shortest middle caudal-fin ray is 57–65% of the longest ray of the upper caudal-fin lobe vs. 40–43), shorter barbels (maxillary barbel 76–90% HL vs. 92–110, inner mandibular barbel 30–33% HL vs. 45–48, outer mandibular barbel 43–49% HL vs. 67–74), and many silvery-beige spots and blotches on head and flank in life (vs. absent).

Glyptothorax alidaeii is distinguished from G. galaxias by having the thoracic adhesive apparatus moderately elevated (vs. strongly elevated) without or with very short anteromedial striae (vs. with numerous and long), pointed caudal fin lobes (vs. rounded), the caudal-peduncle depth 1.3–1.6 times in its length (vs. 1.6–2.1), and head, back and flank with many, irregular shaped and set brown blotches smaller than the eye diameter (vs. as large as the eye diameter or slightly larger).

It is distinguished from G. hosseinpanahii by having the thoracic adhesive apparatus without or with short anteromedial striae (vs. many and long), 1.3 – 1.6 times longer than wide (vs. 1.0–1.2), a pointed (vs. blunt and roundish) short head (head length 21–24% SL vs. 24–28), and the shortest middle caudal-fin ray 57–65% of the longest ray of the upper caudal-fin lobe vs. 42–49).

The new species is distinguished from G. pallens by having the thoracic adhesive apparatus moderately elevated (vs. strongly elevated), 1.3–1.6 times longer than wide (vs. 1.1–1.2), a pointed head (HL 21–24% SL vs. blunt and roundish, 25–28), a moderately deep forked caudal fin (shortest middle caudal-fin ray 57–65% of the longest ray of the upper caudal-fin lobe vs. 47–53).

Glyptothorax alidaeii is distinguished from G. shapuri by having the thoracic adhesive apparatus moderately elevated (strongly elevated), 1.3 – 1.6 times longer than wide (vs. 1.0–1.2), a pointed (vs. blunt and roundish) head (HL 21–24 % SL vs. 24–26), caudal-peduncle depth 1.3–1.6 times in its length (vs. 1.1–1.3), and a moderately deep forked caudal fin (shortest middle caudal-fin ray 57–65% of the longest ray of the upper caudal-fin lobe vs. 46–49).

The new species is further distinguished from G. armeniacus and G. daemon by having the thoracic adhesive apparatus moderately elevated (vs. strongly elevated), with few, very short or no anteromedial striae (vs. numerous and long), pointed caudal fin lobes (vs. rounded); the head, back and flank with many silvery-beige spots and blotches in life (vs. absent);and the thoracic adhesive apparatus 1.3–1.6 times longer than wide (vs. 1.1 – 1.3 in G. daemon ).

Description. Morphometric data as in Table 3 View TABLE 3 . Head depressed; body sub-cylindrical. Dorsal head profile straight, predorsal profile slightly convex: rising from tip of snout to dorsal-fin origin, then straight to adipose-fin origin, sloping gently ventrally from origin of adipose-fin origin to end of caudal peduncle. Ventral profile straight to end of caudal peduncle, slightly convex at belly. Caudal-peduncle depth 1.3–1.6 times its length. Anus and urogenital openings located below adpressed pelvic fin. Skin of back, flank and belly with roundish warts, densely set on head and anterior half of body, sparsely set on posterior half body. Lateral line complete and mid-lateral. Head pointed and short, 21–24% SL. Snout blunt. Anterior and posterior nares large and separated only by base of nasal barbel. Bony elements of dorsal surface of head covered with thick skin, smooth with warts. Eye ovoid, horizontal axis longest; located just below dorsal-head profile. Largest individual recorded 128 mm SL.

Barbels in four pairs. Maxillary barbel broad and thick, extending to or beyond pectoral-fin base, velum at proximal part of barbel attached to head closer to posterior nare than to eye, many warts on outer base of velum, velum smooth. Nasal barbel broad, not reaching to anterior orbital margin. Inner mandibular-barbel extending to isthmus. Outer mandibular barbel extending to end of gill cover, not reaching pectoral-fin origin. Mouth inferior, premaxillary tooth band partially exposed when mouth is closed. Oral teeth small and villiform, in irregular rows on all tooth-bearing surfaces. Premaxillary teeth appearing in single broad semilunate band. Dentary teeth in a single crescentic band, consisting of two separate halves tightly bound at midline.

Thoracic adhesive apparatus consisting of striae in an elongate oblong field extending from isthmus almost to base of the third branched pectoral-fin ray or posterior limit of pectoral-fin base in some specimens ( Fig. 9 View FIGURE 9 ); anterolateral edges of adhesive apparatus strongly convex; its width 1.3–1.6 times in its length; completely situated on a horse-shoe shaped swelling, without warts at its edges. Anteromedial striae short or absent. Narrow medial pit on posterior half of thoracic adhesive apparatus. Dorsal fin located above anterior third of body, with 8–9 branched rays; fin margin straight or slightly concave; spine short and straight, smooth on anterior and posterior margin; distal 1/3 poorly ossified and soft. Adipose fin with anterior margin straight or slightly concave and posterior margin roundish; its origin at vertical through or very slightly in front of anal-fin origin. Caudal fin with pointed lobes, lower lobe slightly longer than upper lobe in some individuals, and i,15,i principal rays. Anal-fin base vertically opposite adipose-fin base. Anal fin with slightly convex anterior margin and slightly concave posterior margin; with 7–8 branched rays. Pelvic-fin origin at vertical in front of tip of adpressed dorsal fin. Pelvic fin with slightly convex anterior and posterior margins, and I,5 rays; tip of adpressed fin reaching anal-fin origin in some individuals. Pectoral fin with I,8–9 rays; posterior fin margin straight; anterior spine margin smooth, with many unculi and a honeycomp pattern on lower surface, inner margin with 10–12 serrae. Back anterior to adipose fin flat or slightly rounded, with a shallow keel in some individuals, expanded distal tips of neural spines not forming a series of bumps.

Coloration. In 70% ethanol: background colouration of head, back and flank pale-grey to greyish brown, fading to pale-grey or beige on ventral surfaces of head, anterior belly and on pectoral and pelvic-fin bases. Head, back, flank and fins with many or few, scattered, dark-brown spots and/or small blotches and many small, palebeige blotches and spots, absent in some long-preserved individuals. Dark-brown spots and blotches smaller than eye diameter in two colours, some darker than background coloration and some lighter than background. Spots and blotches smaller than eye diameter. Latero-sensory pores pale-yellow in posterior half of body, visible as a line lighter in colour compared with surrounding tissue. A pale-grey blotch at dorsal fin origin in most individuals and dorsal fin with a brown base and a brown median band, often incomplete. Adipose fin with a pale-grey blotch behind origin, a brown median band and a pale-grey posterior margin. All other fins with a proximal pale-grey to dark-grey (blackish in caudal fin) base, followed by a yellow band, a dark-grey band and a hyaline or yellow margin; yellow/whitish margin in caudal fin often absent or reduced to a large or small blotch on each lobe. Maxillary and nasal barbels grey or blackish dorsally, pale-grey ventrally, velum pale-grey or beige. Mandibular barbels beige or pale-grey.

In life: background colour of head, back and flank pale-grey to greyish yellow, fading to beige or whitish on ventral surfaces, with few, small irregular black and many silvery-beige spots and / or small blotches on fins, head, back and flank. Silvery-beige pattern ranging in size from minute spots to blotches larger than eye-diameter.

Etymology. The species name alidaeii is in honor of “Ali Daei”, due to his humanitarian activities after the 2018 earthquake in region, where the Seimareh River (type locality of G. alidaeii ) is located.

Distribution. Until now, the species was only found in headwater streams in the upper Karkheh drainage.

Remarks. Freyhof et al. (2021) also reported G. cous from the Seimare River. Glyptothorax cous and G. alidaeii are expected to occur in sympatry. Both are placed in separate molecular clades with a minimum K2P distance of 2.6% between G. cous and G. alidaeii in their DNA barcode sequence.