A new paper is presented by Pablo A. CALVIÑO & Felipe ALONSO in which two new species of corydoras are described. In the same paper Corydoras micracanthus is redescribed and the authors propose a new species group for all three – the Corydoras micracanthus species-group. This group is distinguished by:
dorsal and pectoral spines length reduced; caudal fin slightly emarginated; low body depth; parieto-supraoccipital process and nuchal plate not in contact and small eyes for the genus.
Basically this group of corydoras look very like aspidoras. The first of the new species is Corydoras gladysae
Distinguished from other species of the genus by the caudal-fin shape, slightly emarginated and by presenting the shortest dorsal and pectoral spines length…
Four or five series of small dark brown blotches restricted to rays, forming poorly defined vertical stripe pattern…
Holotype. MACN 9232, 35.0 mm LE; Calchaquí river, (S 25° 2′ 59″ – W 66° 6′ 25″; Altitude: 2430 m.a.s.l.) Payogasta, Cachi Department, Salta province, Argentina. Coll. Felipe Alonso, January 2007…
Emarginated means notched or slightly forked.
Corydoras gladysae is dedicated to its first collector – Gladys Ana María Monasterio de Gonzo, Argentine ichthyologist of the Universidad Nacional de Salta. The authors note that this species lives in areas of high current and quite high pH and salinity. They further state that it rarely displays its caudal fin unfolded.
The second new species is Corydoras petracinii
Distinguished by the following combination of characters: dorsal spine short, pectoral spine short, body moderately elongate, caudal fin slightly forked and trunk flanks with 5–7 subsquare differenced blotches in the middle region…
Holotype. MACN 9233, 36.0 mm SL; small stream 200 m from its ending into the San Lorenzo river (S 24° 47′ 08’’ – W 65° 28′ 10’’; Altitude: 1222 m.a.s.l.), Finca Las Costas, around Salta city, Argentina. Coll. F. Alonso and J. Traine, January 2007.
Corydoras petracinii is named in honour of Roberto Petracini; Argentine fishkeeper. The authors found this species in a single location and warn that the habitat is considerably degraded due to a combination of water extraction, highway construction and rubbish dumping. Consequently they consider this species to be in serious danger.
The rest of the paper is taken up with a re-description of Corydoras micracanthus and a detailed justification for placing these fish in the genus Corydoras rather than Aspidoras.
The inclusion of these species in the genus Aspidoras Ihering was evaluated at the beginning because they present a short ossified portion of the pectoral and dorsal spines, and a low body height, characteristic features of this genus. However the parieto-supraoccipital bone shape and fontanel corresponds to Corydoras. Also, the genus Aspidoras presents a diagnostic character defined by a foramen in the supraoccipital which is not present in these species.
The authors open the possibility that a new genus may be appropriate for this group. There is also a nice description of some of their habits in the fast flowing rivers in which they are found in particular the way they swim and feed seems to allow for a quick manoeuver to avoid quick striking predators such as birds. All in all a very interesting group of fish.