Dzieduszyckia intermedia ( Termier, 1936 )

Baliński, Andrzej & Biernat, Gertruda, 2003, New observations on rhynchonelloid brachiopod Dzieduszyckia from the Famennian of Morocco, Acta Palaeontologica Polonica 48 (3), pp. 463-474 : 468-470

Dzieduszyckia intermedia ( Termier, 1936)

Figs. 7 , 8 .

Halorella intermedia nov. sp.; Termier 1936: 1201, pl. 12: 14–16.? Halorella aff. amphitoma var. semialata ; Termier 1936: 1201,

pl.13:1–3.

Halorella intermedia var. α Termier; Termier and Termier 1948: 47, figs. 6, 7; 1950: 73, pl. 100: 6–8.

Halorella intermedia var. β Termier; Termier and Termier 1948: 48, figs. 8, 9; 1950: 73, pl. 98: 41, pl. 100: 9, 10.

Halorella intermedia var. alta Termier ; Termier and Termier 1950: 73, pl. 100: 6–8.

Halorella intermedia var. globosa Termier ; Termier and Termier 1948: 48, fig. 14; 1950: 74, pl. 100: 3.

? Halorella semialata Termier ; Termier and Termier 1948: 48, figs. 15, 16; 1950: 74, pl. 98: 45, 46, pl. 100: 13, 14.

Leiorhynchus (?) intermedius ( Termier, 1936); Drot 1964: fig. 88.

Lectotype: here designated; ZPAL Bp XVII/37−6, Bou−Nebedou , Morocco; Late Devonian, Famennian; illustrated by Termier (1936, pl. 12: 14) and re−illustrated here in Fig. 7A .

Remarks.—According to Biernat (1967: 144, 145) the distinction among some of the species of “ Halorella ” from Morocco is weak and not very decisive. She noted that differences between H. crassicostata Termier and Termier, 1948 and H. intermedia Termier, 1936 and its varieties were not taxonomically very important. From a purely morphological point of view, there is no possibility to clearly separate the two species in the studied collection (see also biometric diagrams in Termier and Termier 1948: figs. 1–3). However, it may be easier to regard the two forms as valid species when they constitute isolated temporally or spatially populations. This problem, however, cannot be solved at present on a basis of the studied collection, because its stratigraphic and litho−facies context is poorly known.

Termier and Termier (1948) paid attention to the great morphologic variability of D. intermedia and described its new varieties (i.e. α, β, globosa, alta, and semialta; see Fig. 7A–E ). It is noteworthy that analogous phenotypes can be also recognized among D. crassicostata (see Fig. 6B, C ). Strange form of the shell of Termiers’ H. semialata was considered by them as a result of teratology ( Termier 1936; Termier and Termier 1948). Astonishingly, this form develops a surprisingly consistent morphology of the shell, which is expressed mainly in developing a weaker radial ornamentation confined usually to the median sector of the shell and in asymmetric lobate elongation of one postero−lateral extremity ( Fig. 7B, C ). It seems unlikely that this kind of invariable deformation was caused simply by living conditions in a crowded associations. It is more probable that the abnormal shell morphology of H. semialata was a result of a more specific cause, such as, for example, of infestation by an unknown parasitic or commensal organism.

The internal structure of two sectioned specimens of D. intermedia ( Fig. 8 ) seems to be very similar, if not identical, with that in D. crassicostata . Minor differences can be noted in the structure of the dental plates, which in the sectioned specimens are subparallel to slightly divergent ventrally. Distal parts of the crura seem to be more massive, less laterally compressed but, most likely, it is merely a result of recrystallization.

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

Figures

Fig. 7. Dzieduszyckia intermedia (Termier, 1936) from the Famennian of Morocco. A. Lectotype ZPAL Bp XVII/37−6 from Bou Nebedou in dorsal (A1), ventral (A2), lateral (A3), posterior (A4), and anterior (A5) views; figured also in Termier (1936: pl. 12: 14) and Termier and Termier (1950: pl. 100: 9). B. Morphotype alata ZPAL Bp XVII/8−8 from Ahellal in dorsal (B1), ventral (B2), lateral (B3), posterior (B4), and anterior (B5) views. C. Morphotype alata ZPAL Bp XVII/41−1 from Bou Nebedou in dorsal (C1), ventral (C2), lateral (C3), posterior (C4), and anterior (C5) views; figured also in Termier (1936: pl. 13: 3). D. Morphotype globosa ZPAL Bp XVII/28−1 from Bou Nebedou in dorsal (D1), lateral (D2), and anterior (D3) views figured also in Termier and Termier (1950: pl. 100: 3). E. Large shell ZPAL Bp XVII/2−7 from Touchchent in dorsal (E1), lateral (E2), and anterior (E3) views. All in natural size.

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. 6. Dzieduszyckia crassicostata (Termier and Termier, 1948) from the Famennian of Morocco. A. Globose shell ZPAL Bp XVII/27−1 from Itzer in dorsal (A1), lateral (A2), and anterior (A3) views. B. Young shell ZPAL Bp XVII/3−2 from Touchchent in dorsal (B1), lateral (B2), and anterior (B3) views. C. Young shell ZPAL Bp XVII/3−5 from Bou Nebedou in dorsal (C1), lateral (C2), and anterior (C3) views; figured also in Termier (1936: pl. 11: 15) and Termier and Termier (1950: pl. 98: 45). D. Lectotype ZPAL Bp XVII/17−16 from Bou Nebedou in dorsal (D1), ventral (D2), lateral (D3), posterior (D4), and anterior (D5) views; figured also in Termier (1936: pl. 12: 1). E. Large shell ZPAL Bp XVII/4−3 from Touchchent in dorsal (E1), lateral (E2), and anterior (E3) views. All in natural size.