Cyclaster texanus
Plate: CyTe-10
Series: Lower Cretaceous Group: Washita Formation: Weno
Locale: Fort Worth County: Denton Stage: Albian
Length: 18.2 mm Width: 14.9 mm Height: 7.9 mm
Specimen in photo: NPL 70928 (Holotype)
Repository: Non-vertebrate Paleo. Lab., Univ. of Texas
HOLOTYPE INFO:
Holotype: NPL 70928 — Non-vertebrate Paleontology Laboratory, University of Texas
Locality: Quarry in Fort Worth, Denton County, Texas
SYSTEMATIC PALEONTOLOGY – TAXONOMY
Class: Echinoidea Leske, 1778
Subclass: Euechinoidea Bronn, 1860
Infraclass: Irregularia Latreille, 1825
Superorder: Atelostomata Zittel, 1879
Order: Spatangoida L. Agassiz, 1840
Suborder: Micrasterina Fischer, 1966
Family: Micrasteridae Lambert, 1920
Subfamily: Cyclasterinae Poslavskaya, 1964
Genus: CYCLASTER Cotteau, 1856
Species: Cyclaster texanus Thompson, 2016
TYPE SPECIES: Cyclaster declivus Cotteau, 1856
DIAGNOSIS
A Cyclaster from the Weno formation of Texas, with the anterior paired ambulacra 35% longer than the posterior paired ambulacra .
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Washita
Formations: Weno Formation
Stratigraphic Units: Lower Cretaceous, Albian
Counties: Denton County
Matrix: Soft gray marl
Association: Found in association with several Macraster species .
DESCRIPTION
TOP: Length, width, height: 18.2 mm L × 14.9 mm W × 7.9 mm H
Top shape: Ovate; faint anterior sulcus
Top domed: Rounded and bulbous from anterior end
SIDE: Ambitus: About 1/3rd from base
Side shape: Slightly inflated; long truncated posterior end, sloping anterior end
Apex: Located 1/3rd from posterior end
BOTTOM: Bottom shape: Mostly flat, yet depressed; crushed in holotype
AMB: Amb shape: Narrow, only slightly sunken
Amb primary zones: Paired ambs narrow, petaloid; outer ends are open
Dimensions: Posterior paired ambs are 35% longer than anterior paired ambs
PORE PAIRS: Shape: Unpaired amb pores are slit-like, en chevron, greatly spaced. Paired amb pores are elongated .
TUBERCLES: Primary tubercles: More pronounced aborally, at margin on adoral side, and at plastron
FASCIOLE: Peripetalous fasciole present; Subanal fasciole present
APICAL SYSTEM: Size: Small (less than 1 mm)
Genital pores: 3 gonopores
Madreporite: Small
PERIPROCT (ANUS): Shape & Size: Longitudinally oval; measures 1.6 mm tall by 1.3 mm wide; slight point top and bottom
Location: On truncated posterior end; base starts above midpoint at distance of 10% of total height
Visibility: Can be seen from above
PERISTOME (MOUTH): Size: 1.7 mm wide by 1.8 mm tall; slightly larger than periproct
Shape: Subpentagonal; flat on bottom edge
Visibility: Cannot be seen from anterior end
SPECIMENS STUDIED & CONDITION
One small specimen found (Holotype NPL 70928). Bottom of specimen is crushed .
ETYMOLOGY: Named "texanus" after the great state of Texas .
REMARKS & COMPARISONS
Remarks: Aborally, C. texanus is shaped like Cyclaster ovalis and Cyclaster vilanovae, but has a much smaller profile from the side. The peristome is not reniform and lacks the protruding lip typical of most Cyclaster species, though this may be due to the crushing of the specimen .
Comparisons:
Remarks (12-29-2025): Stratigraphy Check: The occurrence of Cyclaster (typically Paleocene-Eocene) in the Albian (Lower Cretaceous) Weno Formation is unusual, but the description describes Cyclaster traits (3 gonopores). This may represent an early lineage or a related Micrasterid.
Plate: CyTe-10
Series: Lower Cretaceous Group: Washita Formation: Weno
Locale: Fort Worth County: Denton Stage: Albian
Length: 18.2 mm Width: 14.9 mm Height: 7.9 mm
Specimen in photo: NPL 70928 (Holotype)
Repository: Non-vertebrate Paleo. Lab., Univ. of Texas
HOLOTYPE INFO:
Holotype: NPL 70928 — Non-vertebrate Paleontology Laboratory, University of Texas
Locality: Quarry in Fort Worth, Denton County, Texas
SYSTEMATIC PALEONTOLOGY – TAXONOMY
Class: Echinoidea Leske, 1778
Subclass: Euechinoidea Bronn, 1860
Infraclass: Irregularia Latreille, 1825
Superorder: Atelostomata Zittel, 1879
Order: Spatangoida L. Agassiz, 1840
Suborder: Micrasterina Fischer, 1966
Family: Micrasteridae Lambert, 1920
Subfamily: Cyclasterinae Poslavskaya, 1964
Genus: CYCLASTER Cotteau, 1856
Species: Cyclaster texanus Thompson, 2016
TYPE SPECIES: Cyclaster declivus Cotteau, 1856
DIAGNOSIS
A Cyclaster from the Weno formation of Texas, with the anterior paired ambulacra 35% longer than the posterior paired ambulacra .
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Washita
Formations: Weno Formation
Stratigraphic Units: Lower Cretaceous, Albian
Counties: Denton County
Matrix: Soft gray marl
Association: Found in association with several Macraster species .
DESCRIPTION
TOP: Length, width, height: 18.2 mm L × 14.9 mm W × 7.9 mm H
Top shape: Ovate; faint anterior sulcus
Top domed: Rounded and bulbous from anterior end
SIDE: Ambitus: About 1/3rd from base
Side shape: Slightly inflated; long truncated posterior end, sloping anterior end
Apex: Located 1/3rd from posterior end
BOTTOM: Bottom shape: Mostly flat, yet depressed; crushed in holotype
AMB: Amb shape: Narrow, only slightly sunken
Amb primary zones: Paired ambs narrow, petaloid; outer ends are open
Dimensions: Posterior paired ambs are 35% longer than anterior paired ambs
PORE PAIRS: Shape: Unpaired amb pores are slit-like, en chevron, greatly spaced. Paired amb pores are elongated .
TUBERCLES: Primary tubercles: More pronounced aborally, at margin on adoral side, and at plastron
FASCIOLE: Peripetalous fasciole present; Subanal fasciole present
APICAL SYSTEM: Size: Small (less than 1 mm)
Genital pores: 3 gonopores
Madreporite: Small
PERIPROCT (ANUS): Shape & Size: Longitudinally oval; measures 1.6 mm tall by 1.3 mm wide; slight point top and bottom
Location: On truncated posterior end; base starts above midpoint at distance of 10% of total height
Visibility: Can be seen from above
PERISTOME (MOUTH): Size: 1.7 mm wide by 1.8 mm tall; slightly larger than periproct
Shape: Subpentagonal; flat on bottom edge
Visibility: Cannot be seen from anterior end
SPECIMENS STUDIED & CONDITION
One small specimen found (Holotype NPL 70928). Bottom of specimen is crushed .
ETYMOLOGY: Named "texanus" after the great state of Texas .
REMARKS & COMPARISONS
Remarks: Aborally, C. texanus is shaped like Cyclaster ovalis and Cyclaster vilanovae, but has a much smaller profile from the side. The peristome is not reniform and lacks the protruding lip typical of most Cyclaster species, though this may be due to the crushing of the specimen .
Comparisons:
- Cyclaster regalis: C. texanus is not cordate.
- Cyclaster heberti: C. texanus lacks the elongated shape and posterior keel.
Remarks (12-29-2025): Stratigraphy Check: The occurrence of Cyclaster (typically Paleocene-Eocene) in the Albian (Lower Cretaceous) Weno Formation is unusual, but the description describes Cyclaster traits (3 gonopores). This may represent an early lineage or a related Micrasterid.
