TRIASSIC FISHES FROM SPITZBERGEN 
149 
also other genera). * 1 ) In the Carboniferous they soon flourished exeedingly and became 
wide-spread and during the Permian they were also represented by many forms. They 
are still not unusual in the Triassic, but become rare in the Jurassic and extinct in the 
Lower Cretaceous (Wealden) with Coccolepis Agassiz (Woodward, 1898 a, pp. 84—86; 
1915, p. 23 ; Traquair, 1911 b, pp. 9—15). 
From the Triassic, which is of special interest to us in this connection, the 
following genera are described: Acrolepis Agassiz (Woodward, 1912, pp. 292—293; 
Lambe, 1916, pp. 42—44), 2 ) Apatheolepis A. S. Woodward (Woodward, 1890 a, pp. 12—15), 
Atherstonia A. S. Woodward (Woodward, 1889 d; i 8 g 3 a, pp. 3 g 3 —397, Broom, 1913 a, p. 3 ), 
Helichthys Broom (1909 a, pp. 254—258), Gyrolepis Agassiz (Stolley, 1920, pp. 25—29, 
75, 79, 83 ), Myriolepis Egerton (Woodward, 1890 a, pp. 7—11; 1891 b, p. 515) 3 ), Oxygnathus 
Egerton (Broom, 1909 a, pp. 259—262), Palaeoniscus Blainville (Woodward, 1908 a, p. 22), 4 ) 
Pygopterus Agassiz (Stolley, 1920, p. 81) and Urolepis Belotti (De Alessandri, 1910, 
pp. 42—49). From strata which might possibly be Triassic but whose age is not quite 
certain we have in addition the genera Elonichthys Giebel (Lambe, 1916, pp. 3 g—42), 
Psilichthys Hall (Hall, 1900), and a supposed Palaeoniscid fish Turseodus Leidy (cfi 
Woodward, 1891 b, p. 527) really not determinable. 5 ) 
In the Triassic rocks of Spitzbergen are found several genera of Palaeoniscids and 
it is evident that the Palaeoniscids there constitute an important part of the fish fauna. 
In 1912 Woodward described a number of Palaeoniscid remains in the material 
collected by B. Hogbom. The new material now present contains a number of additional 
forms and at present we know no less than five genera, Birgeria Stensio (1919, pp. 177 
—181), Glaucolepis n. g., Pygopterus Agassiz, Boreosomus n. g. and Acrorliabdus n. g. 
Birgeria is, as we shall see, established for a species that is identical with or at 
any rate very closely related to the species Saurichthys mongeoti Agassiz. As far as one 
can judge at present, Glaucolepis seems to resemble Gyrolepis. The species mentioned by 
Woodward 1912 (p. 293) under the name of Myriolepis? sp. has with the more complete 
material now present, turned out to belong to the genus Pygopterus, while the forms 
that he referred te to the genus Acrolepis on the same occasion have revealed themselvet as 
J J Cf. Woodward, A. S., 1916, Quart. Journal, Geol. Soc. vol. 72 p. LXXX. 
z ) The species described by Lambe as Acrolepis laetus from deposits of probable lower Triassic age in • the 
district of Alberta, Canada presumably does not belong to the genus Acrolepis. The Acrolepis species described 
from Spitzbergen undoubtedly represent a new genus as we shall see. 
I cannot say anything as to the conditions of the two Tasmanian species A. hamiltonii Johnstone and Morton 
and A. tasmanicus Johnstone and Morton as the literature about these was not accessible to me (cf. Chapman, 1914). 
3 ) The doubtful Myriolepis from Spitzbergen, noticed by Woodward in 1912 (p. 293), seems in fact to 
belong to Pygopterus Agassiz. 
*) Woodward is doubtful (1908 a, p. 22) and probably with justice, whether the species from the Triassic 
described as Palaeoniscus really belong to this genus. 
5 ) Chapman in 1914 (p. 264) put Psilichthys among the Jurassic fishes. On the other hand in the same work 
(p. 263) he considers that all the fish genera described from the Hawkesbury series at St. Peter’s (Woodward. 
1908 a) are of upper Triassic age. Thus he even includes the species that Woodward expressly states to be of 
Permo-Carboniferous age. With reeard to the Palaeoniscids this means that, besides the genera mentioned above, 
Elpisopholis A. S. Woodward ougth also to occur in the Triassic. In this case, however, Chapman’s view does not 
seem probable. 
