Branneroceras sp. B
|
publication ID |
https://doi.org/ 10.37520/fi.2022.021 |
|
DOI |
https://doi.org/10.5281/zenodo.7541585 |
|
persistent identifier |
https://treatment.plazi.org/id/03925E10-FFDA-4240-F07B-DD7CFBDDF887 |
|
treatment provided by |
Felipe |
|
scientific name |
Branneroceras sp. B |
| status |
|
Text-fig. 13v–z View Text-fig
2018 Branneroceras branneri View in CoL ; Dernov, p. 11, pl. 5, fig. 4, pl. 6, fig. 4.
M a t e r i a l. Three specimens of small conch and several fragments of conch from stratigraphic level No. 5a of the Mospyne Formation.
D e s c r i p t i o n. Specimen IGSU-4/626 is an almost fully limonitized specimen with 13.7 mm diameter ( Text-fig. 13v, w View Text-fig ). The conch is discoidal (ww/dm = 0.46) with wide umbilicus (uw/dm = 0.50) and moderately depressed whorl profile (ww/wh = 1.85); the venter is broad and weakly convex; the ventrolateral shoulder is broadly rounded. The flanks are weakly convex and narrow, they slightly converge with the ventrolateral shoulder. The umbilical margin is narrowly rounded. The umbilical wall is weakly convex and at a 45º angle to the plane of symmetry of the conch. The surface of the conch is covered with weak elongated umbilical nodes and growth lines and well-developed lirae on the venter and ventrolateral shoulders. The growth lines form a shallow, broad sinus on the venter, a low projection on the ventrolateral shoulder and a broad shallow sinus on the flanks. On the umbilical margin, the growth lines are spaced about 0.15 to 0.20 mm apart. There are three or four lirae per mm on the ventrolateral shoulder. Three weak concavoconvex constrictions with a high ventrolateral projection and a very shallow ventral sinus are prominent on the whorl.
Specimen IGSU-4/3984а ( Text-fig. 13x, y View Text-fig ) is discoidal (ww/dm = 0.45) with a wide umbilicus (uw/dm = 0.53) and a moderately depressed whorl profile (ww/wh = 1.87) at 12.9 mm diameter. The venter is broad and weakly convex. The ventrolateral shoulder is broadly rounded. The flanks are narrow and weakly convex, they slightly converge onto the ventrolateral shoulder. The umbilical margin is narrowly rounded. The umbilical wall is weakly convex and at an angle of 45º to the plane of symmetry of the conch. The surface of the conch is covered with elongated umbilical nodes and growth lines; lirae on the venter and ventrolateral shoulders are not preserved. Three weak concavo-convex constrictions with a high ventrolateral projection and a very shallow ventral sinus are prominent on the whorl.
R e m a r k s. Branneroceras sp. B differs from Branneroceras branneri ( SMITH, 1896) in the weak constrictions, which are absent in Branneroceras branneri . Branneroceras sp. B is distinguished from B. hillsi Nassichuk by the less elongated umbilical nodes. Branneroceras sp. B differs from Branneroceras nicholasi Nassichuk in the more depressed whorl profile, less frequent constrictions and a wider umbilicus. Branneroceras sp. B differs from Branneroceras sp. A by the greater relief on the umbilical nodes and a more depressed whorl profile.
O c c u r r e n c e. Late Bashkirian, Mospyne Formation, Donets Basin ( Ukraine).
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.