Percalates colonorum
| Percalates colonorum | ||||||||||||
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1921 drawing from the Illustrated Catalog of the Fishes of South Australia by Edgar Ravenswood Waite |
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| Scientific name | ||||||||||||
| Percalates colonorum | ||||||||||||
| ( Günther , 1863) |
Percalates colonorum is an Australian fresh and brackish water fish found in the coastal rivers and lagoons of southeastern Australia. The distribution area extends from the Richmond River in the extreme northeast of the Australian state of New South Wales to the mouth of the Murray River in the southeast of South Australia . Percalates colonorum is a popular frogfish in its homeland and is called Estuary Perch, Brackish Water Perch, Estuarine Perch, Gippsland Perch or simply Perch.
features
Percalates colonorum has a typical, laterally flattened perch shape and can reach a maximum length of 75 cm and a maximum weight of 10 kg. However, most specimens are only 40 cm long and 3 kg in weight. 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. The edge of the preoperculum is finely serrated and has spines pointing forward below. 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. It extends to the base of the caudal fin. The caudal fin is slightly indented. The hard and soft rayed sections of the dorsal fin are separated from one another by an indentation. 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.
- Fin formula : dorsal VIII-IX / 8-11, anal III / 7-9, pectoral 12-16, ventral I / 5
- Scale formula : SL 48-55, mLR 26-32
- Vertebra: 25
On the back, the fish are dark gray to green-brown and become increasingly lighter with a silvery sheen towards the bottom. The lower sides and the belly are silvery-white to yellow-white. Some specimens have a purple to reddish tinge on the head. The fins are dark brown to gray, often with a greenish tinge and, with the exception of the pectoral fins, become increasingly darker towards the tip. Young fish up to 11 cm in length have a dark spot behind the eye and dark spots between the spines on the gill cover.
Percalates colonorum can easily be confused with Percalates novemaculeata , its only close relative, and hybridizes with this species in the catchment area of the Snowy River and in the Gippsland region . Percalates colonorum and Percalates novemaculeata can be distinguished from each other by the concave head profile, the lighter, more silvery coloration and the white anterior dorsal fin spines of P. colonorum .
Way of life
Percalates colonorum occurs in standing and flowing fresh waters and in slightly brackish estuaries and lagoons. In rivers, the species prefers the lower reaches where the tides can still be felt. In deeper water, Percalates colonorum can be found near the bottom of the water. It feeds on small fish, mollusks, worms, shrimp and other crustaceans. In the time of the southern winter (July, August) or in the spring (October, November), the fish migrate to the estuaries of the rivers and spawn over rocks or at the base of aquatic plants at water temperatures of 14 to 19 ° C. The numerous, round eggs have a diameter of 2.3 to 2.4 mm and do not adhere to stones or other objects. The fry hatch after two to three days. Males are sexually mature with a length of about 22 cm, females are then about 28 cm long.
Systematics
The fish species was first scientifically described in 1863 by the German ichthyologist Albert Günther under the name Lates colonorum , at that time it was assigned to the giant perch (Latidae). Later it was transferred to the genus Macquaria , which belongs to the cod perch (Percichthyidae). In a phylogenetic study on the relationship of bony fish, first published in 2013, however, the result was that Percalates colonorum and Percalates novemaculeata do not belong to the genus Macquaria and the codfish, but form a separate clade within the order Centrarchiformes . Therefore, it was proposed to transfer both species to the genus Percalates , which was introduced in 1887 by the Australian zoologists James Douglas Ogilby and Edward Pierson Ramsay with Lates colonorum as the type species , and to establish a monotypical family Percalatidae for Percalates . Both suggestions have now been incorporated into Eschmeyer's Catalog of Fishes, a monthly updated database on fish classification.
supporting documents
- ↑ a b c d e f g Bray, DJ & Thompson, VJ, 2017, Macquaria colonorum in Fishes of Australia , accessed March 23, 2019.
- ↑ a b c d Macquaria colonorum on Fishbase.org (English)
- ↑ a b Percalates colonorum in the Catalog of Fishes (English)
- ↑ 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