Protozoa - Spumellaria - Praeconocaryommidae
Named by Carter.
Original description: Multi-layered cortical shell with mammae, some having remnants of short, circular primary spines. Distal surfaces of mammae low to moderately raised with relatively flat surfaces; usually hexagonal (occasionally pentagonal or septagonal) in shape. Each mamma usually surrounded by six massive triangular mammary pore frames whose outer vertices link with other mammae forming an interlocking meshwork. Inner layer(s) of shell with triangular pore frames that apparently are connected to the inner surface of external mammae directly or are connected by some type of pillar-like structures. Inner layer of pore frames slightly rotated, but usually aligned. Size of pore frames gradually decreasing towards center of test.Central structure of test unknown.
It is interesting to note that the outer shell structure of P. sarahae n. sp. closely parallels that of the genus Pseudopantanellium Yeh, and species P. floridum Yeh. Both species are approximately the same age which suggests the possibility that some type of horizontal gene transfer (Dumitrica & Guex, 2003) may have been operational during this time.
Original remarks: Praeconocaryomma sarahae n. sp. differs from P. parvimamma Pessagno & Poisson in lacking the six small pores that surround the base of each mamma. Pessagno & Poisson (1991) suggest that P. parvimamma is probably the earliest and simplest form of the genus Praeconocaryomma. P. sarahae n. sp. is even simpler morphologically and may be the older of the two.
Etymology: Named for Sarah K. Carter, a mammal biologist and ecologist for her help with the authors research and her constant support.
Full reference: S. Gorican, E. S. Carter, P. Dumitrica, P. A. Whalen, R. S. Hori, P. De Wever, L. O'Dogherty, A. Matsuoka, and J. Guex. 2006. Catalogue and systematics of Pliensbachian, Toarcian and Aalenian radiolarian genera and species 446
Belongs to Praeconocaryomma according to Carter 2006
Sister taxa: Praeconocaryomma bajaensis, Praeconocaryomma californiaensis, Praeconocaryomma copiosa, Praeconocaryomma decora, Praeconocaryomma hexagona, Praeconocaryomma jiangzeensis, Praeconocaryomma lipmanae, Praeconocaryomma mamillaria, Praeconocaryomma matsuokai, Praeconocaryomma media, Praeconocaryomma parvimamma, Praeconocaryomma scatebra, Praeconocaryomma splendida, Praeconocaryomma universa, Praeconocaryomma vivenkensis, Praeconocaryomma yakounensis
Type specimen: GSC 111747. Its type locality is Maude Island, west of Ells Bay; GSC loc. C-304568, which is in a Pliensbachian marine limestone in the Fannin Formation of Canada.
Ecology: passively mobile planktonic omnivore
Distribution:
• Jurassic of Austria (1 collection), Canada (8: British Columbia), Japan (1)
Total: 10 collections each including a single occurrence
Specimen images are retrieved through the ePANDDA API.
Click image to enlarge. Click to access iDigBio record.