Temnholectypus limitis (Bose, 1910)
Plate: TeLi-10
Series: Upper Cretaceous Group: Washita Formation: Main Street
Locale: Lake Arlington County: Tarrant Stage: Albian
Length: 39.7 mm Height: 18.7 mm
Specimen in photo: Collection of Frank Crane
Repository: Private Collection
Plate: TeLi-20
Series: Upper Cretaceous Group: Washita Formation: Main Street
Locale: Lake Arlington County: Tarrant Stage: Albian
Length: 38.5 mm Height: 18.0 mm
Specimen in photo: Collector: Matt (unknown)
Repository: Private Collection
HOLOTYPE INFO:
Holotype: Originally described by Böse (1910). Repository: Instituto Geológico de México (IGM).
Locality: Subdivision 5, Cerro de Muleros, Chihuahua (near El Paso, Texas).
Stratigraphy: Duck Creek / Fort Worth Formation equivalents.
SYNONYMY
SYSTEMATIC PALEONTOLOGY – TAXONOMY
Class: Echinoidea Leske, 1778
Subclass: Euechinoidea Bronn, 1860
Infraclass: Irregularia Latreille, 1825
Superorder: Holectypoida Ducrotay de Blainville, 1825
Order: Holectypoida Ducrotay de Blainville, 1825
Family: Holectypidae Lambert, 1900
Genus: TEMNHOLECTYPUS Lambert, 1918
Species: Temnholectypus limitis (Böse, 1910)
TYPE SPECIES: Holectypus macropygus Desor, 1842
DIAGNOSIS
A Temnholectypus distinguished from C. planatus by having a smaller periproct (length about half the radius of the test) situated approximately halfway between the peristome and the ambitus. In C. planatus, the periproct is larger and occupies nearly the entire space between the peristome and ambitus (Adkins, 1918).
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Washita
Formations: Weno, Pawpaw, Main Street, Grayson.
Stratigraphic Units: Lower Cretaceous (Albian) to Upper Cretaceous (Cenomanian).
Counties: Tarrant.
Abundance: Abundant in the basal marl of the Weno; sparse in Main Street (Adkins, 1918).
Associated Fauna: Enallaster bravoensis, Macraster wenoensis, Hemiaster riovistae, Dumblea symmetrica, Holaster sp. (Adkins, 1918).
DESCRIPTION
TOP: Length, width, height: 39.7 mm L × 18.7 mm H (TeLi-10). Top shape: Subpentagonal to circular.
SIDE: Side shape: Low-arched/depressed.
BOTTOM: Bottom shape: Concave.
AMB: Amb shape: Straight.
PORE PAIRS: Arrangement: Uniserial.
TUBERCLES: Distribution: Small and perforate/crenulate.
FASCIOLE: Absent in Holectypidae.
APICAL SYSTEM: Location: Central. Genital pores: 5.
PERIPROCT (ANUS): Size: Length is about half the radius of the test. Location: Inframarginal; located halfway between the centrally located peristome and the ambitus (Adkins, 1918). Distance: Located within 3 to 4 interambulacral plates distance from the peristome.
PERISTOME (MOUTH): Location: Central.
LANTERN: Hemipyramids: Claw-shaped; inside edge curved and feathered, outer edge has a ridge with inside indentation. Size: Large hemipyramid is 90% the length of the peristome height.
SPINES: Shape: Lanceolate, evenly tapered. Features: Large protruding collar; base smaller than collar, tip even smaller. Size: Largest spine is 70% of peristome height; largest spines are 4 times larger than smallest spines.
SPECIMENS STUDIED & CONDITION:
ETYMOLOGY
From the Latin limes (limit/boundary), possibly referring to its stratigraphic position or the boundary between the periproct and peristome.
REMARKS & COMPARISONS
Remarks: This species is assigned to Temnholectypus based on the position of the periproct, which is separated from the peristome by several plates (3–4), unlike Coenholectypus sensu stricto where the periproct is much larger and closer to the peristome. Cooke (1946) considered C. limitis a synonym of C. transpecosensis (Cragin), but Adkins (1918) maintained it as a distinct species characteristic of the Upper Washita beds of North Texas.
Comparisons:
Plate: TeLi-10
Series: Upper Cretaceous Group: Washita Formation: Main Street
Locale: Lake Arlington County: Tarrant Stage: Albian
Length: 39.7 mm Height: 18.7 mm
Specimen in photo: Collection of Frank Crane
Repository: Private Collection
Plate: TeLi-20
Series: Upper Cretaceous Group: Washita Formation: Main Street
Locale: Lake Arlington County: Tarrant Stage: Albian
Length: 38.5 mm Height: 18.0 mm
Specimen in photo: Collector: Matt (unknown)
Repository: Private Collection
HOLOTYPE INFO:
Holotype: Originally described by Böse (1910). Repository: Instituto Geológico de México (IGM).
Locality: Subdivision 5, Cerro de Muleros, Chihuahua (near El Paso, Texas).
Stratigraphy: Duck Creek / Fort Worth Formation equivalents.
SYNONYMY
- Holectypus limitis Böse, 1910
- Coenholectypus limitis (Böse) Cooke, 1946
- Holectypus transpecosensis Cragin, 1893 (fide Cooke, 1946)
SYSTEMATIC PALEONTOLOGY – TAXONOMY
Class: Echinoidea Leske, 1778
Subclass: Euechinoidea Bronn, 1860
Infraclass: Irregularia Latreille, 1825
Superorder: Holectypoida Ducrotay de Blainville, 1825
Order: Holectypoida Ducrotay de Blainville, 1825
Family: Holectypidae Lambert, 1900
Genus: TEMNHOLECTYPUS Lambert, 1918
Species: Temnholectypus limitis (Böse, 1910)
TYPE SPECIES: Holectypus macropygus Desor, 1842
DIAGNOSIS
A Temnholectypus distinguished from C. planatus by having a smaller periproct (length about half the radius of the test) situated approximately halfway between the peristome and the ambitus. In C. planatus, the periproct is larger and occupies nearly the entire space between the peristome and ambitus (Adkins, 1918).
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Washita
Formations: Weno, Pawpaw, Main Street, Grayson.
Stratigraphic Units: Lower Cretaceous (Albian) to Upper Cretaceous (Cenomanian).
Counties: Tarrant.
Abundance: Abundant in the basal marl of the Weno; sparse in Main Street (Adkins, 1918).
Associated Fauna: Enallaster bravoensis, Macraster wenoensis, Hemiaster riovistae, Dumblea symmetrica, Holaster sp. (Adkins, 1918).
DESCRIPTION
TOP: Length, width, height: 39.7 mm L × 18.7 mm H (TeLi-10). Top shape: Subpentagonal to circular.
SIDE: Side shape: Low-arched/depressed.
BOTTOM: Bottom shape: Concave.
AMB: Amb shape: Straight.
PORE PAIRS: Arrangement: Uniserial.
TUBERCLES: Distribution: Small and perforate/crenulate.
FASCIOLE: Absent in Holectypidae.
APICAL SYSTEM: Location: Central. Genital pores: 5.
PERIPROCT (ANUS): Size: Length is about half the radius of the test. Location: Inframarginal; located halfway between the centrally located peristome and the ambitus (Adkins, 1918). Distance: Located within 3 to 4 interambulacral plates distance from the peristome.
PERISTOME (MOUTH): Location: Central.
LANTERN: Hemipyramids: Claw-shaped; inside edge curved and feathered, outer edge has a ridge with inside indentation. Size: Large hemipyramid is 90% the length of the peristome height.
SPINES: Shape: Lanceolate, evenly tapered. Features: Large protruding collar; base smaller than collar, tip even smaller. Size: Largest spine is 70% of peristome height; largest spines are 4 times larger than smallest spines.
SPECIMENS STUDIED & CONDITION:
- Specimen 1 (TeLi-10): Collection of Frank Crane. Main Street Fm.
- Specimen 2 (TeLi-20): Collection of Matt (Unknown). Preserves spines and lantern elements.
ETYMOLOGY
From the Latin limes (limit/boundary), possibly referring to its stratigraphic position or the boundary between the periproct and peristome.
REMARKS & COMPARISONS
Remarks: This species is assigned to Temnholectypus based on the position of the periproct, which is separated from the peristome by several plates (3–4), unlike Coenholectypus sensu stricto where the periproct is much larger and closer to the peristome. Cooke (1946) considered C. limitis a synonym of C. transpecosensis (Cragin), but Adkins (1918) maintained it as a distinct species characteristic of the Upper Washita beds of North Texas.
Comparisons:
- Coenholectypus planatus: T. limitis has a significantly smaller periproct that does not occupy the full oral radius.
