Sisoridae, Bleeker, 1858

Freyhof, Jörg, Yoğurtçuoğlu, Baran, Jouladeh-Roudbar, Arash & Kaya, Cüneyt, 2025, Handbook of Freshwater Fishes of West Asia, GmbH, Berlin / Boston: De Gruyter : 601-603

Family Sisoridae

Torrent catfishes

The family comprises approximately 17 genera and 220 species of rheophilic catfishes, with the greatest diversity observed in South and Southeast Asia. One species, Bagarius bagarius , reaches up to 1400 mm SL, while most species are small. Most are highly adapted to live in rapids and very fast-flowing waters, with some ( Oreoglanis ) inhabiting the vertical part of waterfalls. Some species are found in high-altitude streams in the Himalayas, while the greatest diversity of species is observed in rapids of tropical rivers. In West Asia, only Glyptothorax is found, which is the most speciose genus of the family. Glyptothorax is immediately identified by a thoracic adhesive organ on the breast between the pectorals. The adhesive organ is sometimes referred to as a “sucker,” which does not suck to the substrate, but instead adheres with small unculi on elevated skin folds, a structure similar to the feet of gecko lizards. Glyptothorax are adapted to live in fast-flowing waters and are commonly found in foothill rivers and mountain streams.

In our region, 13 species are recognised, but six species from Iran are closely related, and their status is under discussion. Two of these ( G. alidaeii and G. galaxias ) occur in sympatry and are good biological species. Other species may be conspecific with G. silviae , but not all morphological differences have been studied in detail. Three widespread species inhabit large- or medium-sized rivers, while others are restricted to fast-flowing headwater streams with more restricted distribution ranges. A single record of Glyptothorax from the Yeşilırmak in the Anatolian Black Sea basin has been identified, although the integrity of this record cannot be confirmed.

Further reading. Hora & Silas 1952 (diversity); Sayyadzadeh et al. 2022 (diversity in Gulf basin).

Key to species of Glyptothorax in West Asia

1a - Adipose length 1.5–3.0 times longer than distance between base of last dorsal ray and adipose origin; 13–17 serrae on pectoral spine, medial pit of thoracic adhesive apparatus with striae. ……………… G. steindachneri

1b - Adipose length 0.5–1.2 times longer than distance between base of last dorsal ray and adipose origin; 5–14 serrae on pectoral spine; medial pit of thoracic adhesive apparatus without striae. ………………2

2a - Head and flank with tubercles (rarely absent in some individuals). ………………3

2b - Head and flank without tubercles, with roundish or elongate warts. ………………4

3a - Thoracic adhesive apparatus longer than wide, well delineated at its posterior margin, situated completely on a horse-shoe-shaped elevation; head, back, and flank with many minute tubercles and few roundish warts. ……………… G. armeniacus

3b - Thoracic adhesive apparatus as wide as long, poorly delineated at its posterior margin, only partly situated on shallow, horseshoe-shaped elevation, elevation absent in many adult individuals; head, back, and usually flank with large, bony, striated, and elongated tubercles (absent in some individuals). ……………… G. cous

4a - Upper head, back, and flank without brown or black spots or blotches. ………………5

4b - Upper head, back, and flank with few or many dark-brown spots and, or blotches (potentially faded in poorly preserved individuals). ………………6

5a - Outer mandibular barbel not reaching pectoral origin; thoracic adhesive apparatus slightly elevated; medial pit broad, its anterior end roundish; caudal peduncle depth 1.6–2.3 times its length. ……………… G. sardashtensis

5b - Outer mandibular barbel reaching pectoral origin; thoracic adhesive apparatus strongly elevated; medial pit narrow and spear-blade shaped; caudal peduncle depth 1.1–1.3 times its length. ……………… G. pallens

6a - Thoracic adhesive apparatus wider than long, as wide as long in juveniles (0.7 – 0.9 times longer than wide). ………………7

6b - Thoracic adhesive apparatus as wide as long or longer, 1.0–1.6 times longer than wide. ………………8

7a - Caudal-peduncle length 16–20 % SL. ……………… G. vatandousti

7b - Caudal-peduncle length 13–16 % SL. ……………… G. kurdistanicus

8a - Anteromedial striae in thoracic adhesive apparatus long and numerous. ………………9

8b - Anteromedial striae in thoracic adhesive apparatus short or absent. ………………11

9a - Caudal-peduncle depth 1.3–1.6 times in its length; shortest middle caudal ray 42–49 % of longest ray of upper caudal lobe; caudal with pointed lobes; maxillary barbel as long as head (95–108 % HL). ……………… G. hosseinpanahii

9b - Caudal-peduncle depth 1.6–2.5 times in its length; shortest middle caudal ray 55–65 % of longest ray of upper caudal lobe; caudal with rounded lobes; maxillary barbel shorter than head (72–91 % HL). ………………10

10a - Fins with a distinct yellow tip; thoracic adhesive apparatus 1.3–1.5 times as long as wide; adipose length 0.5–0.8 of distance between base of last dorsal ray and adipose origin. ……………… G. galaxias

10b - Fins without or with a very indistinct yellow tip; thoracic adhesive apparatus 1.1–1.3 times as long as wide; adipose length 0.7–1.1 of distance between base of last dorsal ray and adipose origin. ……………… G. daemon

11a - Maxillary barbel as long as head (92–110 % HL); inner mandibular barbel 45–48 % HL; outer mandibular barbel

67–74 % HL. ……………… G. silviae

11b - Maxillary barbel shorter than head (76–89 % HL); inner mandibular barbel 18–33 % HL; outer mandibular barbel 42–49 % HL. ………………12

12a - Shortest middle caudal ray 57–65 % of longest ray of upper caudal lobe; caudal-peduncle depth 1.3–1.6 times in its length. ……………… G. alidaeii

12b - Shortest middle caudal ray 46–49 % of longest ray of upper caudal lobe; caudal-peduncle depth 1.1–1.3 times in its length. ……………… G. shapuri

Figures

Glyptothorax