Coenholectypus ovatus Whitney & Kellum, 1966
Plate: CoOv-10
Series: Lower Cretaceous Group: Trinity Formation: Glen Rose
Locale: Canyon Lake County: Comal Stage: Lower Albian
Length: 27.2 mm Height: 16.2 mm
Specimen in photo: NPL 82998 (Hypotype)
Repository: Non-vertebrate Paleo. Lab., Univ. of Texas
HOLOTYPE INFO:
Holotype: UMMP 52174 (Holotype) — University of Michigan Museum of Paleontology (Whitney & Kellum, 1966)
Locality: 3 miles west of Fischer Store, Comal County, Texas (Whitney & Kellum, 1966)
Stratigraphy: Upper Glen Rose Formation (Whitney & Kellum, 1966)
Systematic Paleontology
CLASS: ECHINOIDEA Leske, 1778
SUBCLASS: EUECHINOIDEA Bronn, 1860
INFRACLASS: IRREGULARIA Latreille, 1825
SUPERORDER: GNATHOSTOMATA Zittel, 1879
ORDER: HOLECTYPOIDA Duncan, 1889
FAMILY: COENHOLECTYPIDAE Smith & Wright, 1999
GENUS: COENHOLECTYPUS Pomel, 1883
SPECIES: Coenholectypus ovatus (Whitney & Kellum, 1966)
TYPE SPECIES: Discoidea depressa L. Agassiz, 1839
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Trinity
Formations: Glen Rose Formation (Whitney & Kellum, 1966)
Stratigraphic Units: Lower Cretaceous, Albian (Whitney & Kellum, 1966)
Counties: Comal County
DESCRIPTION
TOP: Length, height: 27.2 mm L ×16.2 mm H
Top shape: Circular from above
Convexity: Sides and top equally curved with a smoother curve between
SIDE: Ambitus: 1/3rd distance from bottom
Side shape: Sub-globular
BOTTOM: Bottom shape: Concave
AMB: Amb shape: Lanceolate
Amb width: Widest part at ambitus
Amb primary tubercles: Tubercles are 4 wide, growing to 6 wide at ambitus
INTERAMB: Interamb width: Twice the size of ambulacra
Interamb primary tubercles: Tubercles are 8 wide, growing to 16 wide at ambitus
Distribution: Largest tubercles on adoral surface near ambitus and the entire aboral surface
PORE PAIRS: Shape: Obliquely round
Arrangement: Offset; very tight on aboral surface; space considerably near adoral surface
TUBERCLES: Primary tubercles: Finely perforated, finely crenulate
APICAL SYSTEM: Genital pores: 5 gonopores in small tight star pattern
PERIPROCT (ANUS): Location: Starts just above ambitus (marginal/supramarginal); extends all but 20% of space to peristome
PERISTOME (MOUTH): Size: Takes up 1/3rd of bottom
Shape: Ovate; transverse with periproct
Lip: Notches: Two notches 6 times larger than other 8 notches, creating the ovate shape
Sunken: Sunken
SPECIMENS STUDIED & CONDITION: Hypotype NPL 82998 .
ETYMOLOGY: From the Latin ovatus, meaning "egg-shaped," referring to the globular outline.
REMARKS & COMPARISONS
Remarks: Coenholectypus ovatus was originally described as Holectypus ovatus by Whitney & Kellum (1966). It is distinguished by its sub-globular shape and the specific arrangement of the peristome notches.
Comparisons: Whitney & Kellum (1966) distinguished this species from Holectypus planatus (Roemer) by its more globular shape, higher ambitus, and the marginal position of the periproct (which starts above the ambitus), whereas planatus is flatter with an infra-marginal periproct.
Plate: CoOv-10
Series: Lower Cretaceous Group: Trinity Formation: Glen Rose
Locale: Canyon Lake County: Comal Stage: Lower Albian
Length: 27.2 mm Height: 16.2 mm
Specimen in photo: NPL 82998 (Hypotype)
Repository: Non-vertebrate Paleo. Lab., Univ. of Texas
HOLOTYPE INFO:
Holotype: UMMP 52174 (Holotype) — University of Michigan Museum of Paleontology (Whitney & Kellum, 1966)
Locality: 3 miles west of Fischer Store, Comal County, Texas (Whitney & Kellum, 1966)
Stratigraphy: Upper Glen Rose Formation (Whitney & Kellum, 1966)
Systematic Paleontology
CLASS: ECHINOIDEA Leske, 1778
SUBCLASS: EUECHINOIDEA Bronn, 1860
INFRACLASS: IRREGULARIA Latreille, 1825
SUPERORDER: GNATHOSTOMATA Zittel, 1879
ORDER: HOLECTYPOIDA Duncan, 1889
FAMILY: COENHOLECTYPIDAE Smith & Wright, 1999
GENUS: COENHOLECTYPUS Pomel, 1883
SPECIES: Coenholectypus ovatus (Whitney & Kellum, 1966)
TYPE SPECIES: Discoidea depressa L. Agassiz, 1839
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Trinity
Formations: Glen Rose Formation (Whitney & Kellum, 1966)
Stratigraphic Units: Lower Cretaceous, Albian (Whitney & Kellum, 1966)
Counties: Comal County
DESCRIPTION
TOP: Length, height: 27.2 mm L ×16.2 mm H
Top shape: Circular from above
Convexity: Sides and top equally curved with a smoother curve between
SIDE: Ambitus: 1/3rd distance from bottom
Side shape: Sub-globular
BOTTOM: Bottom shape: Concave
AMB: Amb shape: Lanceolate
Amb width: Widest part at ambitus
Amb primary tubercles: Tubercles are 4 wide, growing to 6 wide at ambitus
INTERAMB: Interamb width: Twice the size of ambulacra
Interamb primary tubercles: Tubercles are 8 wide, growing to 16 wide at ambitus
Distribution: Largest tubercles on adoral surface near ambitus and the entire aboral surface
PORE PAIRS: Shape: Obliquely round
Arrangement: Offset; very tight on aboral surface; space considerably near adoral surface
TUBERCLES: Primary tubercles: Finely perforated, finely crenulate
APICAL SYSTEM: Genital pores: 5 gonopores in small tight star pattern
PERIPROCT (ANUS): Location: Starts just above ambitus (marginal/supramarginal); extends all but 20% of space to peristome
PERISTOME (MOUTH): Size: Takes up 1/3rd of bottom
Shape: Ovate; transverse with periproct
Lip: Notches: Two notches 6 times larger than other 8 notches, creating the ovate shape
Sunken: Sunken
SPECIMENS STUDIED & CONDITION: Hypotype NPL 82998 .
ETYMOLOGY: From the Latin ovatus, meaning "egg-shaped," referring to the globular outline.
REMARKS & COMPARISONS
Remarks: Coenholectypus ovatus was originally described as Holectypus ovatus by Whitney & Kellum (1966). It is distinguished by its sub-globular shape and the specific arrangement of the peristome notches.
Comparisons: Whitney & Kellum (1966) distinguished this species from Holectypus planatus (Roemer) by its more globular shape, higher ambitus, and the marginal position of the periproct (which starts above the ambitus), whereas planatus is flatter with an infra-marginal periproct.
