Acanthohoplites aschiltaensis var. aplanatus Sinzow, 1908

Frau, Camille, 2023, The systematic affinities between the Lower Cretaceous Ammonoidea Protacanthoplites abichi (Anthula, 1900) and Acanthohoplites aschiltaensis (Anthula, 1900), European Journal of Taxonomy 888 (1), pp. 137-158 : 148

Acanthohoplites aschiltaensis var. aplanatus Sinzow, 1908

Acanthohoplites aschiltaensis var. aplanatus is based on two, well-preserved, moderate-sized acanthohoplitids from the Mangyshlak Peninsula ( Sinzow 1908: pl. V figs 4–7). The subspecies was subsequently considered as a valid species by Kazansky (1914), as it shows a distinctive morphology (moderately evolute coiling, compressed, quadratic then sub-rectangular whorl section, flattened venter in the juvenile and progressively rounded in the adult with convergent outer flanks on the body chamber, narrowly to broadly rounded umbilical wall) and ornamentation (complex rib and tubercle pattern of the inner whorls, early loss of the feeble lateral tubercles). These features better compare to the character and sculpture of Hypacanthoplites as revised by Kennedy et al. (2000). The species is here transferred to that genus pending further investigation. The individuals figured by Luppov & Drushchits (1958: pl. XLVII fig. 4a–в), Eristavi (1961: pl. II fig. 11) and doubtfully Kazansky (1914: pl. III fig. 48a–c) match Hypacanthoplites aplanatus . The specimen figured by Sinzow (1913: pl. 6 fig. 4) better compares to Acanthohoplites lautum laxa Glazunova (1953) ; the latter taxon having been tentatively transferred to Egoianiceras Avram, 1974 by Frau et al. (2020).