Hemibagrus punctatus (JERDON, 1849)

Porthole Bagrid

SynonymsTop ↑

Bagrus punctatus Jerdon, 1849

Etymology

Hemibagrus: from the Greek hemi, meaning ‘half’ and the generic name Bagrus.

punctatus: from the Latin punctatum, meaning ‘punctuated’, in reference to the colour pattern of this species.

Classification

Order: Siluriformes Family: Bagridae

Distribution

Type locality is ‘Cavery River and its principal tributaries, southern India’, and this species is known only from the Cauvery (aka Kaveri) river system in southern India.

It’s also been recorded from some man-made reservoirs within the Cauvery basin including the Tungabhadra and Kalladaippu.

Confirmed localities include the Kabini, Bhadra and Moyar tributary systems where it was last collected in 1998, the 1980s and 1990-92, respectively.

The IUCN currently list it as Critically Endangered (possibly extinct).

Maximum Standard Length

The largest officially-recorded specimen measures 197 mm although in its original description Jerdon states it can reach ’18 inches and more’.

Maintenance

Likely to prefer dim lighting and access to refuges in the form of driftwood, large rocks or lengths of plastic piping.

An enormous filtration system and dedicated regime of water changes would also be required.

Water Conditions

Temperature: 20 – 27 °C

pH: 6.0 – 7.0

Hardness: 36 – 268 ppm

Diet

Probably feeds on smaller fish and invertebrates in nature, although there should be no need to feed live fish in captivity with related species generally not fussy.

Adults should not require feeding on a daily basis with 1-2 meals per week likely sufficient.

Behaviour and CompatibilityTop ↑

Likely to prove aggressively territorial and incompatible with other fishes in all but the largest public installations.

Reproduction

Unrecorded.

NotesTop ↑

This species has only been available very occasionally in the aquarium trade, and its status in the wild is currently unclear (see ‘Distribution’).

H. punctatus can be distinguished from all congeners by the following combination of characters: flanks with dark spots arranged in vertical columns; eye diameter 14–16 % HL; dorsal to adipose distance 16.3–19.4 % SL.

It can be further distinguished from H. menoda in having a shorter, flatter head (head length 28.1–29.6 % SL vs. 32.7–33.5; head depth 11.9–14.3% SL vs. 14.2–15.3), deeper caudal  peduncle (8.8–9.9% SL vs. 7.5–8.8), and reddish (vs. grey) fins in life, and from H. peguensis in having a shorter  adipose-fin base (10.1–13.2 % SL vs. 14.2–19.3).

H. caveatus cannot easily be confused with the other three species since it uniquely possesses a series of thin black vertical lines and a thin midlateral line on the flanks.

Hemibagrus has been divided into a number of putative species groups which may or may not represent monophyletic assemblages, and following a major review by Ng and Kottelat (2013) H. punctatus is included in the H. menoda group.

Members of this assemblage can be told apart from other congeners by possession of 44–46 vertebrae, an adipose-fin with a relatively short base (< 20 % SL), a colour pattern comprising either distinct black spots arranged in vertical columns or irregular black vertical lines running along the flanks, and normally a reddish or orangish caudal-fin in life.

Currently valid members are H. caveatus, H. menoda, H. peguensis and H. punctatus.

The genus Hemibagrus currently contains 40 nominal species which are distributed east of the Godavari River system in India and south of the Changjiang (Yangtze) drainage in China, with Southeast Asia a particular centre of diversity.

Many species are important food fishes and some are cultured for the purpose, or for sport angling.

Hemibagrus has previously been considered synonymous with Mystus but following Ng and Kottelat (2013) members can be diagnosed by their moderate to large adult size and strongly-depressed head shape with the interorbital region normally flat or slighly convex.

The grouping also shares a number of characters with the genera Sperata and Bagrus, and these three can be separated from other bagrids by the following: mesethmoid highly depressed (vs. not highly depressed), prominent (vs. reduced) dorsoposterior laminar extension of the mesethmoid, the first infraorbital with (vs. lacking) a posterolateral spine, enlarged (vs. moderate or small) premaxilla, and the metapterygoid with a long, free posterior margin (vs. contacting quadrate and hyomandibular).

Hemibagrus can be told apart from Sperata by possession of a a relatively short and slender (vs. enlarged and elongate) interneural and by absence (vs. presence) of a concave surface in the posterior portion of the posttemporal in which lies a portion of the swimbladder.

It’s distinguished from Bagrus by possession of 7, very rarely 8 (vs. 8-10) soft dorsal-fin rays.

References

1. Jerdon, T. C., 1849 - Madras Journal of Literature and Science 15(2): 302-346
   On the fresh-water fishes of southern India. (Continued from p. 149.).
2. Ferraris, C. J., Jr., 2007 - Zootaxa 1418: 1-628
   Checklist of catfishes, recent and fossil (Osteichthyes: Siluriformes), and catalogue of siluriform primary types.
3. Ng, H. H. and C. J., Jr. Ferraris, 2000 - Proceedings of the California Academy of Sciences 52(11): 125-142
   A review of the genus Hemibagrus in southern Asia, with descriptions of two new species.
4. Ng, H. H. and M. Kottelat, 2013 - The Raffles Bulletin of Zoology 61(1): 205-291
   Revision of the Asian catfish genus Hemibagrus Bleeker, 1862 (Teleostei: Siluriformes: Bagridae).