Hemiphylactella, Vigneaux, 1949
|
publication ID |
https://doi.org/ 10.5252/g2017n4a7 |
|
publication LSID |
urn:lsid:zoobank.org:pub:4A8E78AE-A740-4537-BD3C-DF0AA18359CE |
|
persistent identifier |
https://treatment.plazi.org/id/03DE3234-FFEF-C625-FCAA-F90F5AB5D39C |
|
treatment provided by |
Felipe |
|
scientific name |
Hemiphylactella |
| status |
|
Hemiphylactella View in CoL ? crassovicellata Vigneaux, 1949 ( Fig. 2 View FIG )
MATERIAL EXAMINED. — Figured syntype ( Vigneaux 1949: 85, pl. 8, fig. 2), C.B.450. This specimen is here designated as the lectotype of the species.
TYPE LOCALITY. — Salles, Gironde, Aquitaine, France.
AGE. — Serravallian, middle Miocene. DESCRIPTION
Colony encrusting, oligoserial to multiserial, fan-shaped, unilaminar ( Fig. 2A View FIG ). Putative ancestrula similar to later autozooids but smaller, about 215 µm long by 190 µm wide, budding four zooids arranged in a semicircle ( Fig. 2B View FIG ). Later zooids arranged quincuncially, distinct, boundaries marked by raised ridges, rounded polygonal, slightly longer than broad (mean L/W = 1.18). Frontal shield slightly convex, apparently finely granular, imperforate except for a sometime visible single row of marginal areolar pores, on average 10 per zooid, oval to circular, 10-25 µm in diameter ( Fig. 2B, C View FIG ). Orifice placed distally, almost equidimensional, about 65 µm long by 60 µm wide, key-hole shaped (cleithridiate), with the proximal rim straight and two tiny condyles placed proximally to the mid-lateral position ( Fig. 2C View FIG ). A smooth, tubular peristome, more developed and slightly flared proximally, surrounds the orifice ( Fig. 2C View FIG ); oral spine bases absent. Ovicells hyperstomial. Ooecium broader than long, globular to elliptical, apparently finely granular like the frontal shield ( Fig. 2B, C View FIG ). Avicularia absent. Oval pore-chamber windows not observed.
MEASUREMENTS
ZL 364 ± 38, 308-432 (20); ZW 309 ± 38, 229-386 (20); OvL 148 ± 12, 132-183 (16); OvW 205 ± 8, 190-219 (16).
REMARKS
The figured syntype specimen of Hemiphylactella ? crassovicellata is a small colony encrusting a shell fragment. The specimen is poorly preserved.Severe recrystallization prevents the observation of the marginal areolar pores in the majority of the zooids, the orifice is often obliterated by cement or sediment, while porechamber windows seem genuinely absent. The epitaxial calcite cement on the surfaces of the zooids hinders clear observation of the texture of the frontal shield, which is interpreted here as finely granular. Hemiphylactella ? crassovicellata differs from H. pulchra in the lack of oral spine bases and pore-chamber windows, in having a much larger ooecium, which is not cap-like, a smaller key-hole shaped orifice surrounded by a less flared peristome, and an apparently finer granulation of the frontal shield. If our interpretation of the ancestrula is correct, this would imply very early sexual maturity in the colony as ovicells are present in the first generation of budded zooids.
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.