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Archaeocidaris brownwoodensis Schneider, Sprinkle & Ryder, 2005
Plate: ArBr-10 Series: Pennsylvanian Group: Canyon Formation: Winchell (formerly Graford) Locale: Brownwood spillway County: Brown Stage: Kasimovian Length: 260 mm* Specimen in photo: TMM 1967TX60 Repository: Non-vertebrate Paleo. Lab., Univ. of Texas HOLOTYPE INFO: Holotype: TMM 1967TX60 — Non-vertebrate Paleontology Laboratory, Texas Memorial Museum, University of Texas (Schneider et al., 2005) Locality: Lake Brownwood Spillway, Brown County, Texas (Schneider et al., 2005) Systematic Paleontology CLASS: ECHINOIDEA Leske, 1778 SUBCLASS: PERISCHOECHINOIDEA M'Coy, 1849 ORDER: ARCHAEOCIDAROIDA Vadet, 1988 FAMILY: ARCHAEOCIDARIDAE McCoy, 1844 GENUS: ARCHAEOCIDARIS McCoy, 1844 SPECIES: Archaeocidaris brownwoodensis Schneider, Sprinkle & Ryder, 2005 TYPE SPECIES: Cidaris urii Fleming, 1828 STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION Group: Canyon Formations: Winchell Formation (formerly mapped as Graford) (Schneider et al., 2005) Stratigraphic Units: Pennsylvanian, Kasimovian (Missourian) Counties: Brown County DESCRIPTION TOP: Length: 260 mm (Dimension refers to total spine extent; test diameters typically range 34–60 mm per Schneider et al., 2005) Top shape: Possibly round, but specimen is crushed flat in matrix Flatness: Crushed flat AMB: Amb plating: Biserial, sinuous INTERAMB: Interamb width: About 5 times the width of the ambulacra Interamb plate shape: Large, hexagonal, slightly wider than high Arrangement: Interambulacra appear to have 4 columns of plates PORE PAIRS: Shape: Outer pores oval, inner pores rectangular TUBERCLES: Primary tubercles: Large, perforated Primary Perforated: Yes Primary Areola shape: Sunken areole Secondary tubercles: Small scrobicular tubercles line entire edges of plates APICAL SYSTEM: Size / Location: Unknown PERIPROCT (ANUS): Location: Unknown PERISTOME (MOUTH): Size: Width about 1/3 (33%) of test width Lantern: Pyramids pronounced, teeth wide SPINES: Shape: Long; triangular in cross section Ornamentation: Many closely arranged spinules SPECIMENS STUDIED & CONDITION Specimen condition: Holotype crushed with spines . ETYMOLOGY: Named for Brownwood, Texas (or Lake Brownwood), the type locality (Schneider et al., 2005). REMARKS & COMPARISONS Remarks: Archaeocidaris brownwoodensis is a medium to large archaeocidarid. It is notable for often having epibionts (such as the brachiopod Crurithyris and various bryozoans) attached to its spines (Schneider et al., 2005). Comparisons: Distinguished from the co-occurring Archaeocidaris apheles by its larger size and triangular, ornate spines (vs. smooth, hollow spines in apheles) (Schneider et al., 2005). |
