Garra rotundinasus (ZHANG, 2006)

Etymology

Garra: vernacular Gangetic name for a particular species of “sand-digger,” which Francis Buchanan-Hamilton applied as a generic name for bottom-dwelling cyprinids “with no affinity to another genus”.

rotundinasus: from the Latin rotundus, meaning ’round’, and nasus, meaning ‘nose, snout’, in reference to the broadly rounded snout in this species.

Classification

Order: Cypriniformes Family: Cyprinidae

Distribution

Native to the Yiluowadi Jiang (upper Irrawaddy river system) in Yunnan province, southern China.

Type locality is ‘Daying Jiang in Tengchong (Houqiao), Yiluowadi Jiang, upper Irrawaddy River basin, Yunnan Province, China’.

Habitat

No specific details, but likely to inhabit flowing water as per most other members of the genus.

Other species occurring in the Daying River include the congener Garra bispinosa, plus  Lepidocephalichthys berdmorei, Devario apogon, Channa gachua, the introduced cyprinids Rhodeus sinensis and Abbottina rivularis, poeciliid Gambusia holbrooki, synbranchid Monopterus albus and cichlid Oreochromis mossambicus (tilapia).

In addition, the congeners G. qiaojiensis and G. tenchongensis are also endemic to the upper Irrawaddy basin in China.

Maximum Standard Length

150 – 185 mm.

NotesTop ↑

Prior to its description, G. rotundinasus was considered to represent the congener G. gravleyi, but the latter is now accepted to occur only in the Salween and Manipur river basins. These two are separated from all other Garra species in China and Southeast Asia by possession of a weakly-developed proboscis on the snout which is represented by a truncated region anterior to the nostrils.

G. rotundinasus can be distinguished from G. gravleyi by the following combination of characters: 36-37 (vs. 32-34) perforated lateral line scales; 2½ (vs. 3½-4½) scales above the lateral line; 10-11 (vs. 8-9) predorsal scales; a broadly rounded (vs. relatively pointed) snout; absence (vs. presence) of black spots at the base of the branched dorsal-fin rays; presence of a dark spot at the dorsal extremity of the opercle.

It is also similar to the congener G. qiaojiensis in that both species possess 12 circumpeduncular scales and a broadly rounded snout with a single lobed proboscis, but differs by its shorter head length (19.7-21.7 % SL vs. 21.8-23.9 % in G. qiaojiensis), slimmer body (depth 18.5-21.0 % SL vs. 21.6-25.6 %), and a more anteriorly-positioned anus (anus to anal-fin distance 32.1-39.2 % pelvic-fin to anal-fin distance vs. 22.8-28.3 %).

The genus Garra is a particularly enigmatic grouping with new taxa described on a regular basis, while many of the existing ones may represent cases of misidentification or synonyms of other species. Some of the revisions have also been called into question, which has added further confusion. A full generic review would be ideal but is unlikely to materialise given the extensive distribution of its members which range from southern China across much of southeast Asia, India and the Middle East as far as north/central Africa.

Instead a number of less-extensive works published in recent years have resulted in a gradual, but continuing, improvement in knowledge, and it remains possible that the genus will be broken up into smaller taxa since the current assemblage is almost certainly polyphyletic.

Garra species are usually included in the subfamily Labeoninae/Cyprininae or tribe Labeonini (name varies with author) which by recent thinking is further divided into four subtribes; Labeoina, Garraina, Osteochilina, and Semilabeoina (Yang et al., 2012). The putatively monophyletic Garraina comprises a number of genetic lineages including Garra sensu stricto (which also includes Horalabiosa, Phreatichthys and possibly other genera), a small clade comprising Garra cambodgiensis and G. fascicauda (thus rendering Garra polyphyletic), Paracrossocheilus, and Gonorhynchus (which includes Akrokolioplax).

Two Garra species, G. imberba and G. micropulvinus, are placed in the Semilabeoina assemblage, and the generic name Ageneiogarra Garman, 1912 has been suggested for them, although this does not appear to have been widely followed (e.g. Kottelat, 2013). In addition, some genera which were previously considered to be close relatives of Garra species such as Discogobio, Discocheilus and Placocheilus, are now also placed in this subtribe.

All genera currently included in Garraina possess a lower lip modified to form a mental adhesive disc, allowing the fish to cling to surfaces in turbulent conditions. In most species the upper lip is almost entirely reduced and both the upper and lower jaw margins are keratinised, i.e., horny, and used to scrape food items from the substrate.

Garra species are distinguished from other Garraina members by the first two pectoral-fin rays usually being thickened, fleshy and unbranched, possession of 10-11 dorsal-fin rays, and a combination of internal characters. Some species have evolved particular environmental specialisms such as highly reduced eyes in hypogean forms or the ability to survive in thermal springs.

References

1. Zhang, E., 2006 - Raffles Bulletin of Zoology 54(2): 447-453
   Garra rotundinasus, a new species of cyprinid fish (Pisces: Teleostei) from the Upper Irrawaddy River basin, China.
2. Kottelat, M., 2013 - Raffles Bulletin of Zoology Supplement 27: 1-663
   The fishes of the inland waters of southeast Asia: a catalogue and core bibiography of the fishes known to occur in freshwaters, mangroves and estuaries.
3. Nebeshwar, K. and W. Vishwanath, 2013 - Ichthyological Exploration of Freshwaters 24(2): 97-120
   Three new species of Garra (Pisces: Cyprinidae) from north-eastern India and redescription of G. gotyla.
4. Yang, L., M. Arunachalam, T. Sado, B. A. Levin, A. S. Golubtsov, J. Freyhof, J. P. Friel, W-J. Chen, M. V. Hirt, R. Manickam, M. K. Agnew, A. M. Simons, K. Saitoh, M. Miya, R. L. Mayden, and S. He, 2012 - Molecular Phylogenetics and Evolution 65(2): 362-379
   Molecular phylogeny of the cyprinid tribe Labeonini (Teleostei: Cypriniformes).
5. Zhang, E. and Y.-Y. Chen , 2002 - Raffles Bulletin of Zoology 50(2): 459-464
   Garra tengchongensis, a new cyprinid species from the upper Irrawaddy River basin in Yunnan, China (Pisces: Teleostei).