Mirabairdia, Kollmann, 1963
|
publication ID |
https://doi.org/ 10.5852/ejt.2020.727.1183 |
|
publication LSID |
lsid:zoobank.org:pub:85AF63D9-5E9E-4CE0-AEC6-6F7CC8C4D375 |
|
DOI |
https://doi.org/10.5281/zenodo.4340791 |
|
persistent identifier |
https://treatment.plazi.org/id/9F3D1275-FFC5-6419-DCD0-F88D08614AED |
|
treatment provided by |
Plazi |
|
scientific name |
Mirabairdia |
| status |
|
Fig. 9P View Fig
Material examined
ROMANIA • 1 LV; Black Sea , Romanian Continental Shelf , borehole 817LV, sample CM31A; Rhaetian, Upper Triassic; MNHN.F. F63258 View Materials .
Dimensions
L = 687 µm; H = 419 µm; H/L = 0.61.
Occurrence
Romanian Continental Shelf, Black Sea, Rhaetian, Upper Triassic (this paper).
Remarks
Only one LV of the present species was found, in sample CM31A, which hampers its attribution to any known species. It is close to Triebelina sp. F in Bolz 1971 from the Rhaetian, Late Triassic of Tyrol ( Bolz 1971a), later re-attributed to the newly erected Triebelina (Nodobairdia) nodata Bolz, 1971 ( Bolz 1971b) . However, our specimen is significantly smaller than the specimens illustrated in Bolz (1971a, 1971b), which all exceed 1 mm in length; it also differs by having a weaker marginal ridge only expressed along the ventral margin and thorns instead of knots marking the marginal ridge, some possibly being bifid (the lack of spines on the medio-lateral surface may relate to preservation). These differences may be related to ontogeny, Mirabairdia sp. possibly being a young instar of T. (Nodobairdia) nodata Bolz, 1971 as shown by its size. Although the ontogeny of T. (Nodobairdia) nodata Bolz, 1971 was not discussed in detail, this hypothesis might be substantiated by the precision made by Bolz (1971b: 224) that the marginal ridge is only expressed along the ventral margin on small specimens, where it is short and narrow; this corresponds to the type of ridge visible in Mirabairdia sp. Similarly, Bolz (1971b) indicates that in small specimens, the thorns are already strong and long, which is the case in Mirabairdia sp. However, the seemingly bifid nature of some thorns in Mirabairdia sp., as well as the specimen being slightly higher than specimens of the same length listed in Bolz (1971b), lead us to keep this species in open nomenclature until more material can resolve this doubt. Mirabairdia sp. can also be compared to M. longispinosa Kristan-Tollmann, 1978 from the Cordevolian, Early Carnian, Late Triassic of the Cassian Formation ( Kristan-Tollmann 1978) by its much thinner lateral spines.
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.