A new species of the Jurassic (Callovian) brachiopod Septirhynchia from northern Sinai
Septirhynchia hirschi n. sp. is described from the Callovian (Jurassic) strata of Gebel El-Maghara, northern Sinai, Egypt. Significant ontogenetic changes from juvenile to adult include: 1) increase in height of the ventral median septum; 2) change from hypothyridid to mesothyridid pedicle foramen;...
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Veröffentlicht in: | Journal of paleontology 1987-11, Vol.61 (6), p.1156-1172 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | Septirhynchia hirschi n. sp. is described from the Callovian (Jurassic) strata of Gebel El-Maghara, northern Sinai, Egypt. Significant ontogenetic changes from juvenile to adult include: 1) increase in height of the ventral median septum; 2) change from hypothyridid to mesothyridid pedicle foramen; 3) change from a pyriform to a gibbous outline; 4) change from a weakly defined to a strongly defined pedicle sulcus; and 5) change from a relatively straight to a strongly arched lateral commissure. All ontogenetic stages, except for neanic, possessed a pedicle tube. Muscle scars (diductor) were observed for the first time in the genus on several pedicle valve interiors; none were noted on any brachial valve interiors. Juveniles lived epifaunally, attached to the substrate by a small but functional pedicle, while adults lived semi-infaunally with the umbos buried in the mud. |
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ISSN: | 0022-3360 1937-2337 |
DOI: | 10.1017/S002233600002953X |