Pteronisculus cicatrosus WHITE, 1933

Taxonomy

Kingdom: Animalia
Phylum: Chordata
Class: Actinopteri Cope 1871
Order: Palaeonisciformes Hay 1902
Family: Palaeoniscidae Vogt 1852
Genus: Pteronisculus
Species: Pteronisculus cicatrosus
Author Citation WHITE, 1933

Geological Time Scale

Eon: Phanerozoic
Era: Mesozoic
Period: Triassic
Sub Period: None
Epoch: Early
International Age: Dienerian

Stratigraphy

Beaufort Group
Sakamena Formation

Biostratigraphy

Lystrosaurus and Cynognathus Zone
Fish and Ammonite Horizon

Provenance

Acquired by: Purchase/Trade

Location

Ambilobe
Antsiranana Province
Diana Region
Madagascar

• ambilobe
• madagascar
• pteronisculus
• sakamena
• triassic

Comments

Taxonomy from Lehman 1952.

Genus Diagnosis from White 1933, p. 118: "Palæoniscidæ with fusiform bodies, long heads, and large orbits anteriorly placed. Gape wide and suspensorium very oblique. Frontals long with extreme irregular media] and digitate parietal sutures; parietals well developed with short triradiate sensory grooves and produced forwards into conspicuous median “ processes.” Preoperculum bent almost at fight-angles, with upper horizontal limb long and roughly triangular, but truncated by supratemporal margin: long wedge shaped bone “ Y ” in excavated antero—superior margin of operculum. Supratemporal large with anterior arm dividing strap-like intertemporal from frontal; four or five postorbital bones present. Teeth on outer margins of maxilla and dentary numerous, minute and sharply pointed. Fin—raye fine and very numerous, articulated dîstally in pectorals, but throughout in other fins; all distanty dichotomized; fulcra minute. Pectoral fins large, their length exceeding distance between their origin and that of ventralfins, which is somewhat nearer pectoral than anal fins; ventral and unpaired fins well developed, the triangular dorsal being posteriorly placed and somewhat anterior in position to similarly—shaped anal. Posterior half of caudal fin unknown. Scales small and numerous, deeplÿ overlapping, rhomboid in shape, their exposed surfaces covered with ganoine, obliquely ridged, and denticulated posteriorly."

Species Diagnosis from White 1933, p. 120: "A Pteronisculus with fusiform body; maximum depth about equal to length of head with opercular apparatus, and rather less than one—third of total length to base of caudal fin. Length of pectoral fin somewhat less than distance between tip of snout and hinder margin of maxilla. Origin of dorsal fin above thirty—fourth scale—row from pectoral girdle approximately. Scales in about fifty—five vertical rows to base of caudal fin, and ornamented with oblique rugæ and a few finer rugæ running parallel to lower margin of scale on main flank—scales."

Line drawing of the head from White 1933, p. 119:

 

Line drawing from Lehman 1952, p. 69.

References:

White E. I. (1933) New Triassic Palaeoniscids from Madagascar. The Annals and Magazine of Natural History, Tenth Series 10:118-128.

Lehman. J.-P. (1952) Etude complémentaire des poissons de l'Eotrias de Madagascar. Kungliga Svenska Vetenskapsakademiens Handlingar 2:1-201.