Cottaldia rotula Clark, 1915
Plate: CoRo-10
Series: Upper Cretaceous Group: Washita Formation: Buda
Locale: Shoal Creek County: Travis Stage: Cenomanian
Length: 8.7 mm Height: 5.3 mm
Specimen in photo: Collection of Chris Garvie (The Akers Collection)
Repository: Private Collection
HOLOTYPE INFO:
Holotype: USNM 328497 (Lectotype designated by Cooke, 1955) — National Museum of Natural History, Smithsonian Institution
Locality: Shoal Creek, Austin, Travis County, Texas (Clark & Twitchell, 1915)
SYNONYMY
Class: Echinoidea Leske, 1778
Subclass: Euechinoidea Bronn, 1860
Infraclass: Carinacea Kroh & Smith, 2010
Superorder: Echinacea Claus, 1876
Order: Uncertain/Pedinoida
Family: Pedinopsidae Durham, 1966
Genus: COTTALDIA Desor, 1856
Species: Cottaldia rotula Clark, 1915
TYPE SPECIES: Cottaldia benettiae (König, 1820)
DIAGNOSIS
Test small, tumid, subhemispherical, with depressed aboral and adoral surfaces. Ambulacral plates crowded with irregular rows of small primary tubercles; pore pairs in simple series. Interambulacral plates with numerous small irregularly disposed tubercles (Clark & Twitchell, 1915).
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Washita (Clark & Twitchell, 1915)
Formations: Buda Limestone (Shoal Creek limestone) (Clark & Twitchell, 1915)
Stratigraphic Units: Upper Cretaceous, Cenomanian (Clark & Twitchell, 1915)
Counties: Travis County (Inferred from Shoal Creek locality)
DESCRIPTION
TOP: Length, width, height: 8.7 mm L × 5.3 mm H
Top shape: Subhemispherical; tumid (Clark & Twitchell, 1915)
Top domed: Much inflated at the ambitus (Clark & Twitchell, 1915)
Flatness: Aboral surface slightly depressed (Clark & Twitchell, 1915)
BOTTOM: Bottom shape: Adoral surface depressed (more so than aboral) (Clark & Twitchell, 1915)
AMB: Amb shape: Narrow (Clark & Twitchell, 1915)
Amb primary tubercles: Four rows of very small tubercles at the ambitus (Clark & Twitchell, 1915)
Amb arrangement: Compound plates composed of three primary plates with very indistinct sutures (Clark & Twitchell, 1915)
INTERAMB: Interamb width: Wide (Clark & Twitchell, 1915)
Interamb plating: Plates low and slightly bent (Clark & Twitchell, 1915)
Interamb primary tubercles: A row of seven small tubercles crosses each plate nearly horizontally at the ambitus; number reduces toward poles (Clark & Twitchell, 1915)
PORE PAIRS: Arrangement: Uniserial; simple series (Clark & Twitchell, 1915)
Amb primary zones: Narrow poriferous zones (Clark & Twitchell, 1915)
TUBERCLES: Primary Perforated: Yes (Clark & Twitchell, 1915)
Primary Crenulate: No (Clark & Twitchell, 1915) Most Pedinopsids (Cottaldia) are crenulate. This description is preserved as written in the source text but noted here as a potential preservation artifact or species-specific trait.
Arrangement: Irregular rows (Clark & Twitchell, 1915)
APICAL SYSTEM: Size / Location: Small (Clark & Twitchell, 1915)
Condition: Not preserved on specimens examined by Clark & Twitchell.
PERISTOME (MOUTH): Size: Small (Clark & Twitchell, 1915)
Condition: Not preserved on specimens examined by Clark & Twitchell.
SPECIMENS STUDIED & CONDITION
Specimen condition: Specimen in photo is 8.7 mm length .
ETYMOLOGY: From the Latin rotula, meaning "little wheel," likely referring to the small, round shape.
REMARKS & COMPARISONS
Remarks: This species has often been referred to the genus Helodiadema (Lambert, 1927), likely due to the uniserial pores and tuberculation pattern. The small size and "tumid" shape are characteristic.
Comparisons: Distinguished from other Cottaldia species by its depressed poles and specific tubercle counts.
Plate: CoRo-10
Series: Upper Cretaceous Group: Washita Formation: Buda
Locale: Shoal Creek County: Travis Stage: Cenomanian
Length: 8.7 mm Height: 5.3 mm
Specimen in photo: Collection of Chris Garvie (The Akers Collection)
Repository: Private Collection
HOLOTYPE INFO:
Holotype: USNM 328497 (Lectotype designated by Cooke, 1955) — National Museum of Natural History, Smithsonian Institution
Locality: Shoal Creek, Austin, Travis County, Texas (Clark & Twitchell, 1915)
SYNONYMY
- Helodiadema rotula (Clark, 1915)
Class: Echinoidea Leske, 1778
Subclass: Euechinoidea Bronn, 1860
Infraclass: Carinacea Kroh & Smith, 2010
Superorder: Echinacea Claus, 1876
Order: Uncertain/Pedinoida
Family: Pedinopsidae Durham, 1966
Genus: COTTALDIA Desor, 1856
Species: Cottaldia rotula Clark, 1915
TYPE SPECIES: Cottaldia benettiae (König, 1820)
DIAGNOSIS
Test small, tumid, subhemispherical, with depressed aboral and adoral surfaces. Ambulacral plates crowded with irregular rows of small primary tubercles; pore pairs in simple series. Interambulacral plates with numerous small irregularly disposed tubercles (Clark & Twitchell, 1915).
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Washita (Clark & Twitchell, 1915)
Formations: Buda Limestone (Shoal Creek limestone) (Clark & Twitchell, 1915)
Stratigraphic Units: Upper Cretaceous, Cenomanian (Clark & Twitchell, 1915)
Counties: Travis County (Inferred from Shoal Creek locality)
DESCRIPTION
TOP: Length, width, height: 8.7 mm L × 5.3 mm H
Top shape: Subhemispherical; tumid (Clark & Twitchell, 1915)
Top domed: Much inflated at the ambitus (Clark & Twitchell, 1915)
Flatness: Aboral surface slightly depressed (Clark & Twitchell, 1915)
BOTTOM: Bottom shape: Adoral surface depressed (more so than aboral) (Clark & Twitchell, 1915)
AMB: Amb shape: Narrow (Clark & Twitchell, 1915)
Amb primary tubercles: Four rows of very small tubercles at the ambitus (Clark & Twitchell, 1915)
Amb arrangement: Compound plates composed of three primary plates with very indistinct sutures (Clark & Twitchell, 1915)
INTERAMB: Interamb width: Wide (Clark & Twitchell, 1915)
Interamb plating: Plates low and slightly bent (Clark & Twitchell, 1915)
Interamb primary tubercles: A row of seven small tubercles crosses each plate nearly horizontally at the ambitus; number reduces toward poles (Clark & Twitchell, 1915)
PORE PAIRS: Arrangement: Uniserial; simple series (Clark & Twitchell, 1915)
Amb primary zones: Narrow poriferous zones (Clark & Twitchell, 1915)
TUBERCLES: Primary Perforated: Yes (Clark & Twitchell, 1915)
Primary Crenulate: No (Clark & Twitchell, 1915) Most Pedinopsids (Cottaldia) are crenulate. This description is preserved as written in the source text but noted here as a potential preservation artifact or species-specific trait.
Arrangement: Irregular rows (Clark & Twitchell, 1915)
APICAL SYSTEM: Size / Location: Small (Clark & Twitchell, 1915)
Condition: Not preserved on specimens examined by Clark & Twitchell.
PERISTOME (MOUTH): Size: Small (Clark & Twitchell, 1915)
Condition: Not preserved on specimens examined by Clark & Twitchell.
SPECIMENS STUDIED & CONDITION
Specimen condition: Specimen in photo is 8.7 mm length .
ETYMOLOGY: From the Latin rotula, meaning "little wheel," likely referring to the small, round shape.
REMARKS & COMPARISONS
Remarks: This species has often been referred to the genus Helodiadema (Lambert, 1927), likely due to the uniserial pores and tuberculation pattern. The small size and "tumid" shape are characteristic.
Comparisons: Distinguished from other Cottaldia species by its depressed poles and specific tubercle counts.
