Dzieduszyckia Siemiradzki, 1909

Baliński, Andrzej & Biernat, Gertruda, 2003, New observations on rhynchonelloid brachiopod Dzieduszyckia from the Famennian of Morocco, Acta Palaeontologica Polonica 48 (3), pp. 463-474 : 465-466

Genus Dzieduszyckia Siemiradzki, 1909

Dzieduszyckia nov. genus; Siemiradzki 1909: 85.

Dzieduszyckia Siemiradzki, 1909 ; G. Biernat 1967: 145–146.

Eoperegrinella gen. nov.; Ager 1968: 61–63.

Type species: Terebratula ? Kielcenis , by subsequent designation of F. Roemer (1866); Famennian ( Upper Devonian ), Kadzielnia quarry, Holy Cross Mountain, Central Poland .

Species assigned: Terebratula ? Kielcensis F. Roemer, 1866; Trematospira (?) baschkirica Tschernyschev, 1887; Halorella tenuicostata H. Termier, 1936 ; Halorella intermedia H. Termier, 1936 ; Halorella crassicostata Termier and Termier, 1948 ; Dzieduszyckia sonora Noll, Dutro, and Beus, 1984 .

Remarks.—The genus, as well as the type species, D. kielcensis was re−described and re−illustrated by Biernat (1967). She gave emended diagnosis of the genus and designated a type specimen (neotype) of D. kielcensis out of six original specimens of the Pusch’s collection derived from limestone of the Kadzielnia quarry. Several sections of four shells of the D. kielcensis ( Biernat 1967: figs. 2, 3; Fig. 3 ) showed a typical rhynchonelloid interior and thus the taxonomic position of the genus was rectified. This, in turn, allowed the conclusion that the Polish species, as well as several Moroccan ones described as belonging to Halorella ( Termier 1936, 1938; Termier and Termier 1948, 1950) or Eoperegrinella ( Ager 1968, 1972; Ager et al. 1976), are in fact congeneric ( Biernat 1967).

It was suggested by G.A. Cooper (in: Termier and Termier 1949) that the Moroccan Late Devonian Halorella species might be referable to Dzieduszyckia Siemiradzki, 1909 . This suggestion was at first rejected by Termier and Termier (1949), mainly on the grounds that despite the great morphologic resemblance the Polish genus possessed a spiral brachidium.

Later, Biernat (1967) revised the type material of Dzieduszyckia kielcensis from Kadzielnia near Kielce, as well as new material from the Ruda Strawczyńska borehole (about 20 km W of Kielce). She proved that the specimen with a spiral brachidium was an accidental admixture from the Carboniferous of Belgium (see also Roemer 1866), and that the original shells from Kadzielnia represent a true rhynchonelloid.

The present study of the shell interior of the Moroccan species reveals more details concerning the structure of the dental plates, dorsal septum and crura, as well as their variability ( Figs. 4 , 5 , 8 , 9 ). In all sectioned specimens dental plates are distinct but short to very short, confined to the most umbonal region of the valve. They are subparallel to slightly convergent in D. crassicostata and D. tenuicostata , or slightly divergent in sectioned specimens of D. intermedia . The dorsal median septum is high and thicker posteriorly, thin and slightly lowering anteriorly, terminating at about the shell midlength. Crura in all studied species are generally of the ciliform type revealing some similarity with crura of the Late Triassic Halorellidae Ager, 1965 . On the other hand, there are evident differences in the structure of crura relative to that of the Cretaceous Peregrinellidae Dagys, 1968 . The latter possess a mergiform type of crura, which are developed as long, closely set, parallel and relatively straight, not curved ventrally structures. It is therefore suggested here that the subfamily Dzieduszyckinae Savage, 1996 is better placed within the family Halorellidae , instead of Peregrinellidae . Our suggestion is in concordance with the earlier opinion of the Termiers who, based on its striking exterior appearance, included Devonian Moroccan forms to the genus Halorella .

When introducing his new genus Eoperegrinella Ager was aware that it was very close to Dzieduszyckia ( Ager et al. 1972, 1976) and that Biernat (1967) had suggested, before a formal description was published by Ager, that both genera should be regarded as congeneric. Ager et al. (1972: 173) pointed out that the serial section of the type species of Dzieduszyckia published by Biernat (1967) did not show the highly distinctive long, crura characteristic of the Moroccan species. They supposed, however, that this might be merely the result of sectioning that was not continued far enough to show them, or that the crura had been broken off. The present observations prove that, indeed, in almost all specimens sectioned by Biernat, the distal parts of the crura had not been preserved. However, one of the specimens of D. kielcensis , which we have now re−sectioned, reveals long crura, essentially identical to those in Moroccan species ( Fig. 3 ). According to Ager et al. (1972) the other characters distinguishing Eoperegrinella from Dzieduszyckia are the complete absence of dental plates in Eoperegrinella and the asymmetry of the latter in Dzieduszyckia . However, a few years later, Ager et al. (1976: figs. 5, 6) showed that dental plates were present in Eoperegrinella from Morocco. Their presence and the intraspecific variability is also illustrated in the present paper ( Figs. 4 , 5 , 8 , 9 ).

According to Biernat (1967), one of the characteristic features of the shell of Dzieduszyckia kielcensis is its asymmetry. Ager et al. (1972) however, did not find asymmetry in the Moroccan specimens. The present study of the Termiers’ collection reveals that the asymmetric condition of the anterior commissure and lateral shell lobes in E. crassicostata , and especially in D. intermedia , does occur (see also Termier 1936: pl. 11: 13, 14, 17, pl. 12: 14, 15). In conclusion, there is no reason to distinguish Eoperegrinella from Dzieduszyckia and thus both genera should be regarded as congeneric, with the priority of the latter. This view is also supported in the recent revision of the Dzieduszyckiinae systematics by Savage (2002).

Figures

Fig. 3. Transverse serial sections of Dzieduszyckia kielcensis (Roemer, 1866) from the Famennian of Ruda Strawczyńska borehole (ZPAL Bp X/895.4 m), Central Poland. Numbers refer to distances in mm from the posterior of the ventral umbo.

Fig. 4. Transverse serial sections of Dzieduszyckia crassicostata (Termier and Termier, 1948) from the Famennian of Bou Nebedou, Morocco (ZPAL Bp XVII/59−1). Numbers refer to distances in mm from the posterior of the ventral umbo.

Fig. 5. Transverse serial sections of two specimens of Dzieduszyckia crassicostata (Termier and Termier, 1948) from the Famennian of Touchchent (A, ZPAL Bp XVII/54−1) and Bou Nebedou (B, ZPAL Bp XVII/59−2), Morocco. Numbers refer to distances in mm from the posterior of the ventral umbo.

Fig. 8. Transverse serial sections of two specimens of Dzieduszyckia intermedia (Termier, 1936) from the Famennian of Brouha Ahellal (A, ZPAL Bp XVII/61−1) and Touchchent (B, ZPAL Bp XVII/60−1), Morocco. Numbers refer to distances in mm from the posterior of the ventral umbo.

Fig. 9. Transverse serial sections of two specimens of Dzieduszyckia tenuicostata (Termier, 1936) from the Famennian of Bou Nebedou, Morocco (A, ZPAL Bp XVII/62−1; B, ZPAL Bp XVII/62−2). Numbers refer to distances in mm from the posterior of the ventral umbo.