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

Mousavi-Sabet, Hamed, Eagderi, Soheil, Vatandoust, Saber & Freyhof, Jörg, 2021, Five new species of the sisorid catfish genus Glyptothorax from Iran (Teleostei: Sisoridae), Zootaxa 5067 (4), pp. 451-484 : 462-468

Glyptothorax galaxias , new species

( Fig. 11–14 )

Holotype. GUIC GTB-H, 113 mm SL; Iran: Chaharmahal-va-Bakhtiari prov. : stream Afsarabad at Afsarabad, 32.1645 50.4232.

Paratypes. FSJF 4112 , 2 , 47–52mm SL ; VMFC GTB-P2, 5, 65–83 mm SL; Iran: Chaharmahal-va-Bakhtiari prov. : stream Beheshtabad at Beheshtabad, 32.0287 50.6265 .— IMNRF-UT-1223 , 3 , 75–108 mm SL ; VMFC GTB-P1, 4, 93–114 mm SL; same data as holotype .— IMNRF-UT-1224 , 2 , 51–60 mm SL; Iran: Chaharmahal-va-Bakhtiari prov. : stream Mal-e-Khalife at Mal-e-Khalife, 31.2800 51.2659 .

Material used in molecular genetic analysis. FSJF-DNA 2611; Iran: stream Behesht Abad north of Ardal, 75 km south-west of Shahr-e-kord, 32.0343 50.6327 (GenBank accession numbers: MW770721 ).— IMNRF-UT-1225 ; Iran: Chaharmahal-va-Bakhtiari prov. : stream Beheshtabad at Beheshtabad, 32.0287 50.6265 (GenBank accession numbers: MZ959025 ).— IMNRF-UT-1223 ; Iran: same data as holotype ( GenBank accession numbers: MZ959026 ).— IMNRF-UT-1224 ; Iran: Chaharmahal-va-Bakhtiari prov. : stream Mal-e-Khalife at Mal-e-Khalife, 31.2800 51.2659 (GenBank accession numbers: MZ959027 ) .

Diagnosis. Glyptothorax galaxias 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 exceptions of G. alidaeii , and G. steindachneri , by having a pointed and short head, 21–24% SL (vs. blunt and spade-shaped, 24–33).

The new species is distinguished from G. silviae by having the thoracic adhesive apparatus with numerous and long anteromedial striae (vs. absent or very short), shorter barbels (maxillary barbel 77–91% HL vs. 92–110, inner mandibular barbel 26–33% HL vs. 45–48, outer mandibular barbel 56–58% HL vs. 67–74), rounded caudal fin lobes (vs. pointed), a less deeply forked caudal fin (shortest middle caudal-fin ray is 61–65% of the longest ray of the upper caudal-fin lobe vs. 40–43), and many, irregular shaped and set dark-brown blotches on flank, as large as the eye-diameter or slightly larger (vs. flank with few spots and small blotches or only small blotches all smaller than eye diameter).

It is distinguished from G. alidaeii by having the thoracic adhesive apparatus strongly elevated (vs. moderately elevated) with numerous and long anteromedial striae (vs. absent or very short), rounded caudal fin lobes (vs. pointed), the caudal-peduncle depth 1.6–2.1 times in its length (vs. 1.3–1.6), and head, back and flank with many, irregular shaped and set brown blotches as large as the eye diameter or slightly larger (vs. smaller than eye diameter).

Glyptothorax galaxias is distinguished from G. hosseinpanahii by having the thoracic adhesive apparatus strongly elevated (vs. moderately elevated), 1.3 – 1.5 times longer than wide (vs. 1.0–1.2), a pointed head (its length 21–23% SL vs. blunt and roundish, 24–28), a smaller eye (eye diameter 10-14% HL vs. 14–17), the caudal-peduncle depth 1.6–2.1 times in its length (vs. 1.3–1.6), rounded caudal fin lobes (vs. pointed), a moderately forked caudal fin (shortest middle caudal-fin ray 61–65% of the longest ray of the upper caudal-fin lobe vs. deeply forked, 42–49), and brown spots and blotches on head, back and flank as large as the eye diameter or slightly larger (vs. smaller than eye diameter).

It is distinguished from G. pallens by having the thoracic adhesive apparatus 1.3–1.5 times longer than wide (vs. 1.0–1.2), many and long anteromedial striae (vs. without or with very short), a pointed (vs. blunt and roundish) and short head (HL 21–23% SL vs. 25–28), the caudal-peduncle depth 1.6–2.1 times in its length (vs. 1.1–1.3), rounded caudal fin lobes (vs. pointed), the shortest middle caudal-fin ray 61–65% of the longest ray of the upper caudal-fin lobe vs. 47–53).

The new species is distinguished from G. shapuri by having the thoracic adhesive apparatus with numerous and long anteromedial striae (vs. very few and short), 1.3 – 1.5 times longer than wide (vs. 1.0–1.2), a pointed (vs. blunt and roundish) head (HL 21–23% SL vs. 24–26), a smaller eye (eye diameter 10–14% HL vs. 16–18), a more narrow caudal-peduncle (caudal peduncle depth 1.6–2.1 times in its length vs. 1.1–1.3), a moderately forked caudal fin (shortest middle caudal-fin ray 61–65% of the longest ray of the upper caudal-fin lobe vs. 46–49), rounded caudal fin lobes (vs. pointed), and head, back and flank with many, irregular shaped and set blotches smaller than eye-diameter, without points (vs. with few, irregular shaped dark-brown blotches as large as eye diameter or larger, and many, very small dark-brown points, much smaller than eye diameter).

Glyptothorax galaxias also differs from G. daemon by having a thoracic adhesive apparatus 1.3 – 1.5 times longer than wide (vs. 1.1–1.3), and from G. kurdistanicus by the thoracic adhesive apparatus extending from the isthmus to the base of last pectoral-fin ray or to the posterior limit of the pectoral-fin base (vs. to base of first or third branched pectoral-fin ray in G. kurdistanicus ).

Description. Morphometric data as in Table 3 . Head depressed; body subcylindrical.Dorsal head profile straight, predorsal profile straight or slightly convex: Profile rising from tip of snout to dorsal-fin origin, then almost straight to adipose fin origin, sloping gently ventrally from origin of adipose fin to end of caudal peduncle. Ventral profile straight to end of caudal peduncle. Caudal-peduncle depth 1.6–2.1 times in its length. Anus and urogenital openings located below tip of adpressed pelvic fin. Skin of back and flank with many roundish warts, often elongated on lateral body and head, sparsely set on head, densely set on flank and belly. Lateral line complete and midlateral. Head is pointed and short, 21–23% SL. Head is square-shaped from dorsal view. 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, without tubercles, with many warts, slightly elongated on gill cover. Eyes small (10–14% HL); ovoid, horizontal axis longest; located just below dorsal-head profile. Largest individual recorded 114 mm SL.

Barbels in four pairs. Maxillary barbel broad and thick, not reaching to pectoral-fin base (reaching in small individuals), velum at proximal part of babel attached to head closer to posterior nare than to eye, thick warts on outer base of velum, velum smooth. Nasal barbel broad, not reaching to anterior orbital margin (reaching in small individuals). Inner mandibular-barbel extending to isthmus. Outer mandibular barbel extending to end of gill cover, not reaching pectoral-fin origin (reaching in small individuals). 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 to posterior end of pectoral-fin base, reaching beyond in some individuals ( Fig. 13 ); anterolateral edges of adhesive apparatus slightly convex, often almost straight; its width 1.3–1.5 times in its length; completely situated on a horse-shoe shaped swelling, associated with few, small warts at its posterior edge and without warts at its lateral edge. Anteromedial striae present, but slightly developed. Narrow medial pit on posterior half of thoracic adhesive apparatus. Dorsal fin located above anterior third of body, with 6 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 convex and posterior margin roundish; its origin at vertical through or very slightly in front of anal-fin origin. Caudal fin with rounded lobes, lower lobe slightly longer than upper lobe and i,15,i principal rays. Anal-fin base vertically opposite adipose-fin base. Anal fin with slightly convex anterior margin and straight or slightly concave posterior margin; with 7 branched rays. Pelvic-fin origin at vertical through or slightly in front of or behind tip of adpressed dorsal fin. Pelvic fin with slightly convex anterior margin and I,6 rays; tip of adpressed fin reaching anal-fin origin. Pectoral fin with I,9 rays; posterior fin margin straight; anterior spine margin smooth, with many unculi and a honey-comp pattern on lower surface, inner margin with 9–12 serrae. Back anterior to adipose fin flat or slightly rounded, with a shallow keep in some individuals, expanded distal tips of neural spines not forming a series of bumps.

Coloration. In 70% ethanol: background colour greyish brown, fading to pale-brown or beige on ventral surfaces of head and anterior belly and on pectoral and pelvic-fin bases. Head, back, flank and fins with many, irregular shaped and set, dark-brown blotches as large as eye diameter or slightly larger, absent or almost absent in some individuals. Latero-sensory pores same colour as surrounding tissue. A pale-brown blotch at dorsal fin origin, usually arc-shape. Dorsal-fin with a brown base and a brown median band. Adipose fin with a pale-brown blotch at origin, a pale-brown posterior margin in some individuals, very narrow or absent in others. All other fins with pale- to dark-brown base, a brown median band and hyaline or yellow margin. Patter often darkened and hyaline or yellowish elements reduced to blotches. Caudal fin with a dark-brown base, a W-shaped, pale-brown or yellowish median band, often reduced to two, median, yellowish blotches, and a whitish margin, often absent or reduced to whitish tips. Maxillary and nasal barbels dark-brown dorsally with hyaline tips, pale-brown ventrally, velum pale-brown or beige. Mandibular barbels beige or pale-brown.

In life: head, back and flank dark-grey to greyish olive, fading to beige or whitish on ventral surfaces, with many, small, dark-brown, irregular shaped and set blotches as large as eye diameter or slightly larger. Bands and blotches on fins whitish, yellowish or orange. Many minutes, star-like, silvery-beige spots much smaller than eyediameter.

Etymology. This species is named for the star-like silvery blotches. A noun in genitive, indeclinable.

Distribution. Headwater streams in the upper Karun drainage.

Figures

FIGURE 11. Glyptothorax galaxias, GUIC GTB-H, holotype, 113 mm SL; Iran: upper Karun at Afsarabad.

FIGURE 12. Glyptothorax galaxias, VMFC GTB-P1, paratypes; from top: 114 mm SL, 105 mm SL, 93 mm SL; 93 mm; Iran: upper Karun; VMFC GTB-P2, 89 mm SL; IMNRF-UT-1224, 60 mm SL; Iran: upper Karun.

FIGURE 13. Glyptothorax galaxias, thoracic adhesive apparatus, top row: VMFC GTB-P1, paratypes; from left: 114 mm SL, 105 mm SL, 93 mm SL; bottom row: paratypes; from left: VMFC GTB-P2, 89 mm SL, 71 mm SL; Iran: upper Karun; IMNRF- UT-1224, 60 mm SL; Iran: upper Karun.

FIGURE 14. Glyptothorax galaxias, from top: VMFC GTB-H, holotype, 113 mm SL; VMFC GTB-P1, paratypes; 114 mm SL, 93 mm SL; Iran: upper Karun.