Cenomanian ammonites from the southern margin of the Westfalian Cretaceous between Unna and Möhnesee

Phenotypic plasticity and taxonomy of Schloenbachia varians (J. Sowerby, 1817) (Cretaceous Ammonoidea)

“…As pointed out by Kennedy (1971), Kennedy et al (1979), Marcinowski (1980), Hiss (1982), Thomel (1992) and Kaplan et al (1998), the morphological variability within the genus is conspicuous and species concepts are not always clearly defined. This has resulted in the establishment of several morphotypes, varieties, subspecies or stratigraphic species (Fig.…”

“…Surprisingly, it was excluded from previous monographic revisions (see Kennedy 1971, 44-45). As pointed out by many authors, e.g., Kennedy et al (1979), Marcinowski (1980), Hiss (1982), Thomel (1992) and Kaplan et al (1998), the morphological variation within the genus is enormous and species concepts are not always clearly defined, resulting in the establishment of several morphotypes (varieties, forms, sometimes regarded as subspecies; see discussion in Hiss 1982) and stratigraphically defined species [i.e., Schloenbachia varians (J. Sowerby, 1817) for Early Cenomanian and S. coupei (Brongniart, 1822) for Middle Cenomanian representatives of the genus].…”

“…Morphotypes range from strongly compressed, relatively involute forms with faint ribbing and weak tuberculation to strongly spinose (hypernodose), depressed and relatively evolute forms (e.g., Juignet and Kennedy 1976;Kennedy et al 1979;Marcinowski 1980;Hiss 1982;Kaplan et al 1998). The genus was probably derived from the latest Albian (Stoliczkaia dispar Zone) Arrhaphoceras (Praeschloenbachia) Scholz, 1973 and had its maximum distribution in the Early Cenomanian (Kaplan et al 1998).…”

On variation in Schloenbachia varians (J. Sowerby, 1817) from the Lower Cenomanian of western Kazakhstan

“…Descriptions of highly variable Schloenbachia collections as single variable species are given by Marcinowski (1983: the Mangyshlak and Tuarkyr regions, western Kazakhstan), Kennedy and Juignet (1984: Sarthe, France), Kaplan, Kennedy, Lehmann and Marcinowski (1998: Westphalia, Germany; see also Hiss, 1982), SeyedEmami and Aryai (1981, northeast Iran; see also Wilmsen and Mosavinia 2011), Immel and Seyed-Emami (1985, Central Iran), Kennedy, Amédro, Robaszynski and Jagt 2011 (southern Belgium and northern France) and others. Cooper and Owen (2011) provided a comprehensive review of late Albian Hoplitoidea, and greatly expanded the scope of the family Schloenbachiidae, to which Wright (1957Wright ( , 1996 had previously referred the genus Schloenbachia only, dividing it into subfamilies Schloenbachiinae, Pleurohoplitinae, and Dimorphoplitinae.…”

Cenomanian ammonites from the condensed deposits of the Helvetic Domain (western Alps, France and Switzerland)

“…-For discussion see Kennedy et al, 1979, p. 28 Discussion.-The wide intraspecific variation shown by spe cies of this genus is well known, following discussions by Juignet and Kennedy (1976), Kennedy et al (1979), Marcinowski (1980), Hiss (1982), and Kennedy and Juignet (1984). Following these authors, only one species is recognized among the present col lection: the Lower Cenomanian S. varians (J. Sowerby, 1817).…”