Eurasian craspeditid genera Temnoptychites and Tollia in the lower valanginian of Sverdrup Basin, district of Franklin, with comments on taxonomy and nomenclature of Craspeditidae
Authors: Jeletzky J A 
Published: July 2015

Lower Valanginian beds of the Deer Bay Formation in Sverdrup Basin, Arctic Canada, are characterized by the numerous representatives of the boreal ammonite Temnoptychites Pavlow 1914 (including subgenera Temnoptychites s. str. and Costamenjaites Sazonova 1971).
They are accompanied by rare representatives of the boreal genus Tollia (s. Jato) Pavlow 1914. The following representatives of these craspeditid genera are described and figured from the Deer Bay Formation: Temnoptychites (Temnoptychites) borealis Bodylevsky 1967 T. (T.) kemperi n. sp.
Temnoptychites (Costamenjaites) grandiosus Voronets 1962 T. (C.) aff. T. (C.) grandiosus Voronets 1962 T. ( C.) troelseni n. sp. subsp. troelseni n. subsp. T. ( C.) troelseni n. sp. subsp. crassus n. subsp. To/lia (s. Jato) aff. T. to/Ii Pavlow 1914 T. (s. Jato) n. sp. aff. T. klimovskiensis
Krimgolts 1953 T. (s. Jato) n. sp. aff. T. vai Krimgolts 1953 T. (s. Jato) n. sp. aff. T. subtilis Voronets 1962 A rev1s1on of taxonomy and nomenclature of Temnoptychites, To/lia and the family Craspeditidae Spath 1924 in general is undertaken in connection with the description of the Deer Bay
representatives of the above-mentioned genera. This revision stresses the outstanding taxonomic value of the external suture line for the recognition of representatives of Craspeditidae in general and that of its individual genera. The details of sculpture and the whorl shape are considered to have
a subordinate taxonomic value for the same purposes. The current proliferation of subgenera, genera and subfamilies of the Craspeditidae is directly attributable to the neglect of the taxonomic value of the external suture line by modem workers combined with an exaggeration of the value of the
sculpture and the whorl shape. This taxonomic procedure is severely criticized and rejected as causing an unnecessarily complicated nomenclature and obstructing interregional zonal correlation of the uppermost Jurassic and early Early Cretaceous rocks. None of the recently proposed subfamilies of
the Craspeditidae are recognized as valid. Furthermore, some craspeditid subgenera and genera (e.g., Volgidiscus Casey 1973; Runctonia Casey 1973; Lynnia Casey 1973; Bojarkia Shulgina 1969; Neotollia Shulgina 1969; Pronjaites Sazonova 1971; Bodylevskyiceras Sazonova 1971; Mosquites Sazonova 1971;
Caseiceras Sazonova 1971; and Nikitinoceras Sokolov 1913) are considered to be entirely superfluous and are synonymized with Craspedites, Surites, Temnoptychites, Praetollia, and Tollia on the generic and subgeneric level. Other genera are either considered to be of doubtful validity (e.g.,
Shulginites Casey 1973; Borea/ites Klimova 1969; Bogoslovskia Sazonova 1971 ; Stchirowskiceras Sazonova 1971) or downgraded to subgenera (e.g., Swinnertonia Shulgina 1972, Menjaites Sazonova 1971; Costamenjaites Sazonova 1971 ). All representatives of Temnoptychites and Tollia known from the lower
Valanginian of Sverdrup Basin are either closely related to or specifically identical with the species previously described from central Russia, European Arctic and northern Siberia. Therefore they are interpreted as migrants from these boreal regions via the early V alanginian seas of northern
Siberia. This circumstance greatly facilitates the intercontinental correlation of the lower V alanginian beds of Sverdrup Basin and the dating of its regional Valanginian and Berriasian fossil zones in terms of the international standard stages and the classical fossil zones of western Europe. At
least two well defined Temnoptychites faunas are recognizable in the lower Valanginian beds of the Deer Bay Formation: Temnoptychites (Temnoptychites) kemperi fauna and Temnoptychites ( Costamenjaites) troelseni fauna. These two faunas define ammonite zones within the lower part of the lower to
middle Valanginian Buchia keyserlingi Zone. The Temnoptychites (Temnoptychites) kemperi Zone immediately underlies the Thorsteinssonoceras ellesmerense Zone and the two faunas mingle in its topmost part. The Temnoptychites (Temnoptychites) kemperi Zone is therefore equated, completely or in part,
with the T. (T.) hoplitoides Zone of central Russia and the T. (T.) syzranicus Zone of northern Siberia. It is assigned the latest early Valanginian age whereas the next younger Thorsteinssonoceras ellesmerense Zone is placed in the earliest mid-V alanginian as defined by the author. Though
Temnoptychites (Temnoptychites) kemperi and Temnoptychites ( Costamenjaites) troelseni zones were not observed in superposition, the latter zone is inferred to be the older of the two and equivalent, in part, to the basal Valanginian Pseudogarnieria undulatoplicatilis Zone of central Russia. First,
there is no room for another fossil zone between Temnoptychites (Temnoptychites) kemperi Zone and the next younger Thorsteinssonoceras ellesmerense Zone. Second, the two Canadian zones contain specifically and subgenerically distinct Temnoptychites forms and so could hardly be fauna! facies of one
and the same zone. Third, T. (C.) grandiosus and T. (C.) troelseni n. sp. belong to the same subgenus as, and are closely related specifically to, Temnoptychites ( Costamenjaites) ex gr. jucundus-suraense of Central Russian Basin. There the latter species characterize the basal Valanginian
Pseudogarnieria undulatoplicatilis Zone which immediately underlies the regional Temnoptychites (Temnoptychites) hoplitoides Zone. The bulk of Tollia (s. Jato) forms hitherto found in Sverdrup Basin are associated either with Temnoptychites (Costamenjaites) troelseni or with Temnoptychites
(Temnoptychites) kemperi fauna. This puts in doubt the previously held idea about the presence of the basal Valanginian Tollia tolli Zone stratigraphically below the generalized Temnoptychites Zone in the Deer Bay Formation. It is not known whether or not the Temnoptychites (Costamenjaites)
troelseni Zone corresponds to all of the central Russian Pseudogarnieria undulatoplicatilis Zone and to all of the presumably equivalent Tollia klimovskiensis and Tollia mesezhnikowi subzones (of Tollia tolli Zone) of northern Siberia. If it corresponds only to the upper part of the Pseudogarnieria
undulatoplicatilis Zone and the Tollia klimovskiensis Subzone, the equivalents of the lower part of the Tollia tolli Zone may be present in those beds in the Deer Bay Formation containing Buchia keyserlingi but so far barren of ammonites, which immediately underlie the Temnoptychites (
Costamenjaites) troelseni Zone. However, these lowermost Valanginian beds may be represented only by a regional late Berriasian and basal (?) Valanginian hiatus recently discovered in the Sverdrup Basin.