Coenholectypus borachoensis Thompson, 2016
Plate: CoBo-10
Series: Upper Cretaceous Group: Washita Formation: Boracho
Locale: Private Property County: Hudspeth Stage: Cenomanian
Length: 32.9 mm Height: 17.5 mm
Specimen in photo: NPL 82985 (Holotype)
Repository: Non-vertebrate Paleo. Lab., Univ. of Texas
HOLOTYPE INFO:
Holotype: NPL 82985 — Non-vertebrate Paleontology Laboratory, University of Texas
Locality: Hudspeth County, Texas
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 borachoensis Thompson, 2016
TYPE SPECIES: Discoidea depressa L. Agassiz, 1839
DIAGNOSIS: Medium Holectypus from the Boracho formation with a periproct that cuts into the margin.
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Washita
Formations: Boracho Formation
Stratigraphic Units: Upper Cretaceous, Cenomanian
Counties: Hudspeth County
DESCRIPTION
TOP: Length, height: 32.9 mm ×17.5 mm
Top shape: Round, only slightly pentagonal
Top domed: Inflated, domed
SIDE: Ambitus: 1/3rd from the adoral side; rounded
Side shape: Inflated
BOTTOM: Bottom flat: Flat
AMB: Amb shape: Lanceolate, very pointed; straight to ambitus
Amb width: Widest at ambitus; adorally begins to narrow
Amb arrangement: Plating unigeminate
INTERAMB: Interamb width: Slightly less than three times the size of ambulacra at ambitus
Interamb plating: Compound plates, much wider than tall; suture plating distinct
PORE PAIRS: Shape: Small, narrow
Arrangement: Uniserial, oblique; more spaced adorally
TUBERCLES: Primary tubercles:
Plates: Genitals pentagonal; 5 gonopores
Madreporite: Large, central
PERIPROCT (ANUS): Shape & Size: Tear-drop shaped; pointed away from center (adapically), rounded toward center (adorally); longer than wide
Location: Cuts into the margin; cannot be seen from above but can be seen from the side
PERISTOME (MOUTH): Size: 32% of diameter of test
Shape: Round
Lip: Notches small
SPECIMENS STUDIED & CONDITION
Three specimens studied; Holotype NPL 82985
ETYMOLOGY: Named for the Boracho formation.
REMARKS & COMPARISONS
Remarks: Coenholectypus borachoensis is characterized by its periproct which "cuts into the margin," a feature distinguishing it from other Coenholectypus species where the periproct is typically infra-marginal (on the oral surface)
Comparisons: The marginal periproct and its specific "outward point" (tear-drop shape pointing away from the peristome) separate this species from typical forms like Coenholectypus planatus or C. transpecosensis.
Plate: CoBo-10
Series: Upper Cretaceous Group: Washita Formation: Boracho
Locale: Private Property County: Hudspeth Stage: Cenomanian
Length: 32.9 mm Height: 17.5 mm
Specimen in photo: NPL 82985 (Holotype)
Repository: Non-vertebrate Paleo. Lab., Univ. of Texas
HOLOTYPE INFO:
Holotype: NPL 82985 — Non-vertebrate Paleontology Laboratory, University of Texas
Locality: Hudspeth County, Texas
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 borachoensis Thompson, 2016
TYPE SPECIES: Discoidea depressa L. Agassiz, 1839
DIAGNOSIS: Medium Holectypus from the Boracho formation with a periproct that cuts into the margin.
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Washita
Formations: Boracho Formation
Stratigraphic Units: Upper Cretaceous, Cenomanian
Counties: Hudspeth County
DESCRIPTION
TOP: Length, height: 32.9 mm ×17.5 mm
Top shape: Round, only slightly pentagonal
Top domed: Inflated, domed
SIDE: Ambitus: 1/3rd from the adoral side; rounded
Side shape: Inflated
BOTTOM: Bottom flat: Flat
AMB: Amb shape: Lanceolate, very pointed; straight to ambitus
Amb width: Widest at ambitus; adorally begins to narrow
Amb arrangement: Plating unigeminate
INTERAMB: Interamb width: Slightly less than three times the size of ambulacra at ambitus
Interamb plating: Compound plates, much wider than tall; suture plating distinct
PORE PAIRS: Shape: Small, narrow
Arrangement: Uniserial, oblique; more spaced adorally
TUBERCLES: Primary tubercles:
- Ambulacra: Small, perforated, faintly crenulated; rows irregular. A primary tubercle is on every third plate and adjacent to a pore pair .
- Interambulacra: Many primary tubercles on each compound plate; irregular distribution. Crenulate and perforate .
Secondary tubercles: Concentrated near perradial suture in ambulacra; somewhat irregular .
Granules: Many granules on interambulacral plates .
Plates: Genitals pentagonal; 5 gonopores
Madreporite: Large, central
PERIPROCT (ANUS): Shape & Size: Tear-drop shaped; pointed away from center (adapically), rounded toward center (adorally); longer than wide
Location: Cuts into the margin; cannot be seen from above but can be seen from the side
PERISTOME (MOUTH): Size: 32% of diameter of test
Shape: Round
Lip: Notches small
SPECIMENS STUDIED & CONDITION
Three specimens studied; Holotype NPL 82985
ETYMOLOGY: Named for the Boracho formation.
REMARKS & COMPARISONS
Remarks: Coenholectypus borachoensis is characterized by its periproct which "cuts into the margin," a feature distinguishing it from other Coenholectypus species where the periproct is typically infra-marginal (on the oral surface)
Comparisons: The marginal periproct and its specific "outward point" (tear-drop shape pointing away from the peristome) separate this species from typical forms like Coenholectypus planatus or C. transpecosensis.
