Zemes un vides zinātnes Earth and Environment Sciences - Latvijas ...

26 ADVANCES IN PALAEOICHTHYOLOGY
of the Okse Bay Group, and the lower part of the Nordstrand Point Formation correlates
with the upper part of the Beverly Inlet Formation (Embry and Klovan 1976). Thus, the
obrucheviids from the Canadian Arctic can be a valuable biostratigraphic tool for
intrabasinal, as well as interbasinal correlations.
Material and methods
The material both from the Canadian Arctic and Russia was collected in a weathered
condition, and preparation has been minimal beyond that needed for repair. The
Obruchevia material is held in the collections of the Natural History Museum of Latvia,
Riga (prefixed Pl), and the Palaeontological Institute, Russian Academy of Sciences,
Moscow (prefixed PIN), and the Canadian Arctic material is held in the collections of
the Canadian Museum of Nature, Ottawa (prefixed CMN).
Systematic palaeontology
Order PTERASPIDIFORMES Berg, 1940
Suborder PSAMMOSTEIDA Tarlo, 1962
Family OBRUCHEVIIDAE Tarlo, 1964
Genus Obruchevia Whitley, 1940
Discussion. The generic name problem. In 1941 D. Obruchev described a peculiar
Late Devonian heterostracan under the name Aspidosteus heckeri gen. nov. sp. nov. He
considered it to be a member of the family Cardipeltidae of the suborder Psammosteida.
Based on this description, Berg (1955) established the family Aspidosteidae in the
order Psammosteiformes. In 1964 Obruchev accepted both the above family and generic
names, and mentioned as a synonym the name Obruchevia, given by Whitley
(1940). Whitley, however, establishing that the name Aspidophorus, preliminarily used
by Obruchev for the heterostracan, was preoccupied, changed the name Aspidophorus
(not Aspidosteus) into Obruchevia. It appeared that Obruchev’s first publication on
this heterostracan appeared in 1936, when in a paper of the popular-scientific journal
Priroda (Nature), he gave a description and figure of the dorsal shield under the name
Aspidophorus heckeri n.gen. n.sp. Obruchev later (1941, 1964) did not refer to his
paper of 1936, and he also did not mention his own usage of the name Aspidophorus
heckeri (nomen nudum) in a stratigraphical paper by Hecker et al. (1935).
Whitley (1940) established that the generic name Aspidophorus was preoccupied
for recent cottoid fishes. In 1940 (or earlier?) Obruchev may have discovered this for
himself, as he renamed the heterostracan Aspidophorus heckeri as Aspidosteus heckeri.
It is not impossible that Whitley did not know of Obruchev’s paper of 1940, published
in a sedimentological symposium volume in October 1940 (in imprint [impressum] the
date is 7 th October 1940). Whitley’s paper was published in May of 1940, thus having
firm priority.