Hypostomus laplatae (Eigenmann, 1907)

Koerber, Stefan & Weber, Claude, 2014, The Hypostominae (Siluriformes: Loricariidae) of Argentina., Ichthyological Contributions of PecesCriollos 29, pp. 1-10 : 4

Hypostomus laplatae (Eigenmann, 1907)

original: Plecostomus laplatae synonyms: Plecostomus commersonoides Marini, Nichols & La Monte, 1933

Plecostomus rachovii Regan, 1913

Plecostomus taeniatus Regan, 1908

remarks: as listed by López et al. (2003)

Hypostomus latifrons Weber, 1996

synonym: Peckoltia vittata NON Steindachner, 1881

type locality: Paraguay, Río Aguaray-guazú , Río Paraguay basin, River Paraná system

One lot of paratypes is from the Río Paraguay where it forms the political border between Paraguay and Argentina (Ita Enramada, 11 km S of Asuncion) .

first record: Meinken (1937) from Río Paraná in Corrientes sub Ancistrus vittatus other records: sub Peckoltia vittata :

- Rodriguez & Cuello (2005): Corrientes, Rio Paraná at Corza-Cué | Corrientes, río

Paraná at Puerto Yahape | Santa Fe, tributary of río Paraná near city of Santa Fe sub Hypostomus latifrons :

- MHNG 2582.052 : Corrientes, Rio Paraná at Corza-Cué

- Bishop & Bishop (2004): Entre Rios, Rio Paraná at city of Paraná sub Hypostomus sp. :

- Almirón et al. (2008): Parque Nacional Pre-Delta, several locations remarks: The specimen in MHNG 2582.052 was identified as H. latifrons in 1996 but this, for being unpublished data, could not be considered to indicate a distrbution in

Argentina in the CLOFFSCA account of this species ( Weber 2003). This was the first time that a collection lot with a locality from Argentina has been determined as

H. latifrons . Meinken’s Ancistrus vittatus still exists (ZMB 32513, coll. C. Hahn,

Corrientes, im Río Paraná, det. H. Meinken, Dez. 1936) and could without doubt be determined as a juvenile Hypostomus latifrons .

Loricariid specialists in the aquarium hobby have established a system of Lnumbers to provide working names to unidentified loricariid species that have been imported for aquarium purposes ( Stawikowski et al., 2004).

A loricariid species imported from Paraguay had been assigned L51 ( Lucas & Mahr,

1989) and was later determined as H. latifrons ( Stawikowski et al., 2004) . Another species from Paraguay initially thought to be either a Peckoltia sp. or a species from the Panaque -dentex -complex was presented as L281 ( Werner, 2000) and later also determined as a juvenile of L51 ( Stawikowski et al., 2004).

Animals of Hypostomus latifrons in an import of aquarium fishes from Paraguay with mixed sizes, showed during their growth that the species starts changing the colour pattern between 70 and 80 mm, losing the typical honeycomb drawings and part of the reddish colour ( figs. 2-4 .). Reaching 100 mm they finish the changing and then show the colour pattern of adults (Ingo Seidel, pers.com. 25.09.06).

Adult H. latifrons are reported to reach 287 mm (longest specimen in type series,

Weber, 1986) and 250-300 mm ( Seidel & Evers, 2005). All specimens reported so far from Argentina have been not larger than 51 mm ( Meinken, 1937) or max. 55.4

mm ( Rodriguez & Cuello, 2005).

The records of Peckoltia vittata from Argentina, all originally based on either

Meinken (1937) or Rodriguez & Cuello (2005), represent juvenile H. latifrons .

All the above shall finally put an end to the myth of Peckoltia species in the La-

Plata-basin.

Figures

fig. 2. Hypostomus latifrons, 6 cm, from Paraguay (photo: Ingo Seidel)

fig. 3. Hypostomus latifrons, 8 cm, from Paraguay (photo: Ingo Seidel)

fig. 4. Hypostomus latifrons, adult, from Paraguay (photo: Ingo Seidel)