Percalates

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Percalates
Percalates colonorum, the type species of the genus

Percalates colonorum , the type species of the genus

Systematics
Acanthomorphata
Spinefish (Acanthopterygii)
Perch relatives (Percomorphaceae)
Order : Sunfish-like (Centrarchiformes)
Family : Percalatidae
Genre : Percalates
Scientific name of the  family
Percalatidae
Lavoué et al., 2014
Scientific name of the  genus
Percalates
Ramsay & Ogilby , 1887

Percalates is a genus of perch-related freshwater fish thatis only two speciesand is endemic to southeast Australia between southern Queensland and eastern South Australia . The two species of the genus are usually placed in the genus Macquaria in the family of codfish (Percichthyidae). Phylogeneticstudies basedon the comparison of DNA show, however, that they arenot closely relatedto the two other Macquaria species, butoccupya basal position in the order Centrarchiformes .

features

Percalates species have a typical, laterally flattened perch shape with a dorsal fin, the soft-nosed section of which is clearly separated from the hard-nosed part by an indentation. Percalates colonorum can reach a maximum length of 75 cm and a maximum weight of 10 kg. Percalates novemaculeata is smaller, with a length of 60 cm and a weight of 3.8 to a maximum of 4.5 kg. The mouth is large and above all. At the back it reaches under the eye. The lower jaw protrudes. The jaw and palate are covered with small teeth arranged in bands. The preoperculum is finely serrated on the upper branch and has strong, forward-facing spines on the lower branch. The gill cover is equipped with two spines, the lower one of which is larger and wider. The scales are medium in size and usually comb scales . "Cheeks" and gill covers are also scaly. The snout, in fish the area between the front edge of the eye and the tip of the mouth, is not scaly. The side line is fully developed and follows the back line in its course. The fourth dorsal fin spine is the longest. The anal fin is symmetrically opposite the soft-rayed section of the dorsal fin. It has three short spines. The upper rays of the pectoral fins are longer than the lower. The base of the pelvic fins is just behind the pectoral fin base. The caudal fin is slightly indented.

On the back, the fish are dark gray to greenish and become increasingly lighter towards the bottom. The lower sides and the belly are silvery-white to yellowish. The fins are dark. Young fish up to a length of 11 to 12 cm have dark spots between the spines on the gill cover.

Way of life

Percalates species occur in rivers, streams, lakes and in slightly brackish estuaries, the species prefer to stay between aquatic plants or rocks and feed on small fish, mollusks, crustaceans and other invertebrates. They spawn in southern winter or spring. The females lay numerous small, round eggs that do not adhere and float freely in the water. The fry hatch after two to three days. Both species hybridize with each other in the catchment area of ​​the Snowy River and in the Gippsland region .

species

Systematics

The genus Percalates was introduced in 1887 by the Australian zoologists James Douglas Ogilby and Edward Pierson Ramsay . Type species is Lates colonorum . MacDonald transferred the type species to the genus Macquaria in 1978 and synonymized Percalates with Macquaria . In a phylogenetic study on the relationship of bony fish, first published in 2013, however, the result was that Percalates novemaculeata and Percalates colonorum do not belong to the genus Macquaria and the codfish, but form a separate clade within the order Centrarchiformes . This was confirmed in 2014 in a further study on the internal systematics of the centrarchiformes and codfish. Therefore it was proposed to revalidate the genus Percalates and to introduce a monotypic family Percalatidae for the genus . Both suggestions have now been incorporated into Eschmeyer's Catalog of Fishes, a monthly updated database on fish classification. The two Percalates species can tolerate brackish water and are euryhaline migratory fish that migrate to the estuaries to spawn in the southern winter. The remaining two Macquaria species ( M. ambigua and M. australasica ), on the other hand, cannot withstand large fluctuations in the salt content (salinity) of the water and are therefore bound to fresh water.

supporting documents

  1. ↑ a b Macquaria colonorum on Fishbase.org (English)
  2. ↑ a b c d e Bray, DJ & Thompson, VJ, 2017, Macquaria colonorum in Fishes of Australia , accessed March 23, 2019.
  3. ↑ a b Macquaria novemaculeata on Fishbase.org (English)
  4. ↑ a b c d e Dianne J. Bray & Vanessa J. Thompson, Macquaria novemaculeata in Fishes of Australia , accessed March 23, 2019.
  5. ↑ a b Sébastien Lavoué, Kouji Nakayama, Dean R. Jerry, Yusuke Yamanoue, Naoki Yagishita, Nobuaki Suzuki, Mutsumi Nishida, Masaki Miya: Mitogenomic phylogeny of the Percichthyidae and Centrarchiformes (Percomorphaceae): based comparison with recent simultaneous nuclear gene-based studies analysis. Gene, July 2014. DOI: 10.1016 / j.gene.2014.07.033
  6. ↑ Ricardo Betancur-R, Edward O. Wiley, Gloria Arratia, Arturo Acero, Nicolas Bailly, Masaki Miya, Guillaume Lecointre and Guillermo Ortí: Phylogenetic classification of bony fishes . BMC Evolutionary Biology, BMC series - July 2017, DOI: 10.1186 / s12862-017-0958-3
  7. ↑ Percalates colonorum in the Catalog of Fishes (English) / Percalates novemaculeata in the Catalog of Fishes (English)