Dzieduszyckia crassicostata, (Termier and Termier, 1948)

Baliński, Andrzej & Biernat, Gertruda, 2003, New observations on rhynchonelloid brachiopod Dzieduszyckia from the Famennian of Morocco, Acta Palaeontologica Polonica 48 (3), pp. 463-474 : 467

publication ID	https://doi.org/ 10.5281/zenodo.13388115
DOI	https://doi.org/10.5281/zenodo.13388230
persistent identifier	https://treatment.plazi.org/id/BD121F17-FFE4-FF9A-FFBF-FB267555F808
treatment provided by	Felipe
scientific name	Dzieduszyckia crassicostata
status

Treatment

Dzeduszyckia crassicostata ( Termier and Termier, 1948)

Figs. 4–6 View Fig View Fig View Fig .

Halorella aff. amphitoma Bronn ; Termier 1936: 1196–1199, pl.11:

8–18, pl. 12: 1, 2. Halorellacrassicostata nov.sp.; Termier and Termier 1948: 47, figs.4, 5. Halorella crassicostata Termier ; Termier and Termier 1950: 73, pl. 98:

39, 40, pl. 100: 1, 2, 17. Eoperegrinella crassicostata (Termier) ; Ager 1968: fig. 5; pl. 1: 6. Eoperegrinella crassicostata (Termier and Termier) ; Ager et al. 1976:

fig. 5.

Lectotype: here designated; ZPAL Bp XVII/17−16, Bou−Nebedou , Morocco; Late Devonian, Famennian; illustrated by Termier (1936, pl. 12: 1) and re−illustrated here in Fig. 6D View Fig .

Remarks.—When Termier and Termier (1948) introduced a new species name for the Halorella aff. amphitoma from the Famennian of Morocco they did not designate a type specimen. This is now rectified by choosing a specimen (lectotype) which not only comes from the original Termiers’ collection, but was originally illustrated by Termier (1936: pl. 11: 1). This specimen has a large, although slightly incomplete shell; however, together with some other original specimens illustrated here it typifies the species sufficiently.

The external morphology of D. crassicostata was described quite sufficiently by Termier (1936) and Termier and Termier (1948). Besides some re−illustrations, additional specimens were illustrated to characterize intraspecific variability (see also plot−diagrams in Termier and Termier 1948: figs. 1–3). It is noteworthy that the species, like other members of the genus Dzieduszyckia , is characterized by a great variability in the general appearance of the shell. Characteristic morphotypes include: more common wide ( Figs. 6D, E View Fig ), elongated heart−shaped ( Fig. 6B, C View Fig ), and wide and very thick, globose shells ( Fig. 6A View Fig ). Ager et al. (1976: 179, fig. 6) also noted an occurrence of a smoother variant of Eoperegrinella (new species?) at Sidi Amar near Khenifra.

Previously, the internal shell structure of all Moroccan species was not fully known. The first important data on the interior of D. crassicostata were presented by Ager (1968: fig. 5) and Ager et al. (1976: fig. 5). They showed for the first time, in one sectioned specimen, the presence of dental plates, horizontal hinge plates, and ciliform crura. New, additional data on the internal shell structure of the species are presented below from serial sections of three specimens ( Figs. 4 View Fig , 5 View Fig ).

Dental plates are short, subparallel to slightly convergent ventrally. Median septum is high posteriorly, gradually lowering anteriorly, reaches about the shell midlength. Muscle field is deeply impressed but in very large specimens only. Hinge plates are short, horizontal. Crural bases are quite closely set, near the ventral surface of the hinge plates and fused with the top of the median septum, embedded in thickened shell material. Crura are proximally rodlike to slightly flattened horizontally, more or less triangular in cross section. Crural blades are slightly divergent, curve uniformly ventrally, becoming thin and wide, vertical, subparallel to slightly divergent ventrally in cross section at distal ends.

Occurrence.—The species is known from the Famennian limestones of several localities near Khenifra and Khouribga (Middle Atlas, Morocco).