Parorthopsis comalensis (Whitney & Kellum, 1966)
Plate: PaCo-10
Series: Lower Cretaceous Group: Trinity Formation: Glen Rose
Locale: Canyon Lake County: Comal Stage: Albian
Length: 13.2 mm Height: 6.6 mm
Specimen in photos: Collection of Ed Elliott
Repository: Private Collection
HOLOTYPE INFO:
Holotype: UMMP 52161 (University of Michigan Museum of Paleontology) (Whitney & Kellum, 1966).
Locality: 2 miles southwest of Wimberley, Hays County, Texas.
Stratigraphy: Glen Rose Limestone (Lower Member), Trinity Group.
SYNONYMY
SYSTEMATIC PALEONTOLOGY – TAXONOMY
Class: Echinoidea Leske, 1778
Subclass: Euechinoidea Bronn, 1860
Infraclass: Carinacea Kroh & Smith, 2010
Superorder: Echinacea Claus, 1876
Order: Camarodonta Jackson, 1912
Family: Parorthopsidae Gottreau, 1889
Genus: PARORTHOPSIS Maury, 1925
Species: Parorthopsis comalensis (Whitney & Kellum, 1966)
TYPE SPECIES: Parorthopsis royi Maury, 1925
DIAGNOSIS
Test small and subhemispherical. Distinguished by imperforate and non-crenulate tubercles. Ambulacra have trigeminate plates with uniserial pores (Smith & Rader, 2009). Interambulacra feature two rows of primary tubercles flanked by secondary tubercles at the ambitus.
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Trinity
Formations: Glen Rose Formation.
Stratigraphic Units: Lower Cretaceous, Albian.
Counties: Comal, Hays.
Abundance: Rare.
DESCRIPTION
TOP: Length, width, height: 13.2 mm L × 6.6 mm H. Top shape: Circular. Top domed: Curved from ambitus to apical disc.
SIDE: Ambitus: Positioned at 40% of height from the bottom. Side shape: Not very inflated.
AMB: Amb shape: Lanceolate; widest at ambitus, narrowing at peristome. Perradial zones raised; pore pair zones sunken. Amb arrangement: Two rows of primary tubercles run the length of the ambulacra. Amb width: Interambulacra are twice the size of the ambulacra.
PORE PAIRS: Arrangement: Uniserial; offset at the peristome. Elements: Trigeminate (Smith & Rader, 2009).
TUBERCLES: Primary Perforated: No (Non-perforated). Primary Crenulate: No (Non-crenulate). Areolas: Raised. Distribution: Interambulacra have two rows of primary tubercles; two rows of secondary tubercles present on both sides of the ambitus. Scrobicular Tubercles: Rings of scrobiculate tubercles surround the primaries.
FASCIOLE: Absent.
APICAL SYSTEM: Size: Diameter about 25% of test. Shape: Dicyclic. Oculars are pentagonal with a waved outer edge. Both genitals and oculars point outward.
PERIPROCT (ANUS): Shape: Large and subpentagonal.
PERISTOME (MOUTH): Size: Large; diameter 48% of test diameter. Shape: Slightly oval. Lip: Equally spaced buccal notches.
SPINES: Unknown.
SPECIMENS STUDIED & CONDITION: One specimen studied from the Collection of Ed Elliott.
ETYMOLOGY
Named for Comal County, Texas, where the type specimens were collected (Whitney & Kellum, 1966).
REMARKS & COMPARISONS
Remarks: Originally described as Orthopsis comalensis by Whitney & Kellum (1966). Orthopsis is characterized by perforate tubercles. Smith & Rader (2009) re-examined the taxon and determined the tubercles are imperforate, necessitating reassignment to the genus Parorthopsis. This is a critical distinction, as imperforate tubercles exclude it from the Orthopsidae.
Plate: PaCo-10
Series: Lower Cretaceous Group: Trinity Formation: Glen Rose
Locale: Canyon Lake County: Comal Stage: Albian
Length: 13.2 mm Height: 6.6 mm
Specimen in photos: Collection of Ed Elliott
Repository: Private Collection
HOLOTYPE INFO:
Holotype: UMMP 52161 (University of Michigan Museum of Paleontology) (Whitney & Kellum, 1966).
Locality: 2 miles southwest of Wimberley, Hays County, Texas.
Stratigraphy: Glen Rose Limestone (Lower Member), Trinity Group.
SYNONYMY
- Orthopsis comalensis Whitney & Kellum, 1966
- Parorthopsis comalensis (Whitney & Kellum, 1966) (fide Smith & Rader, 2009)
SYSTEMATIC PALEONTOLOGY – TAXONOMY
Class: Echinoidea Leske, 1778
Subclass: Euechinoidea Bronn, 1860
Infraclass: Carinacea Kroh & Smith, 2010
Superorder: Echinacea Claus, 1876
Order: Camarodonta Jackson, 1912
Family: Parorthopsidae Gottreau, 1889
Genus: PARORTHOPSIS Maury, 1925
Species: Parorthopsis comalensis (Whitney & Kellum, 1966)
TYPE SPECIES: Parorthopsis royi Maury, 1925
DIAGNOSIS
Test small and subhemispherical. Distinguished by imperforate and non-crenulate tubercles. Ambulacra have trigeminate plates with uniserial pores (Smith & Rader, 2009). Interambulacra feature two rows of primary tubercles flanked by secondary tubercles at the ambitus.
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Trinity
Formations: Glen Rose Formation.
Stratigraphic Units: Lower Cretaceous, Albian.
Counties: Comal, Hays.
Abundance: Rare.
DESCRIPTION
TOP: Length, width, height: 13.2 mm L × 6.6 mm H. Top shape: Circular. Top domed: Curved from ambitus to apical disc.
SIDE: Ambitus: Positioned at 40% of height from the bottom. Side shape: Not very inflated.
AMB: Amb shape: Lanceolate; widest at ambitus, narrowing at peristome. Perradial zones raised; pore pair zones sunken. Amb arrangement: Two rows of primary tubercles run the length of the ambulacra. Amb width: Interambulacra are twice the size of the ambulacra.
PORE PAIRS: Arrangement: Uniserial; offset at the peristome. Elements: Trigeminate (Smith & Rader, 2009).
TUBERCLES: Primary Perforated: No (Non-perforated). Primary Crenulate: No (Non-crenulate). Areolas: Raised. Distribution: Interambulacra have two rows of primary tubercles; two rows of secondary tubercles present on both sides of the ambitus. Scrobicular Tubercles: Rings of scrobiculate tubercles surround the primaries.
FASCIOLE: Absent.
APICAL SYSTEM: Size: Diameter about 25% of test. Shape: Dicyclic. Oculars are pentagonal with a waved outer edge. Both genitals and oculars point outward.
PERIPROCT (ANUS): Shape: Large and subpentagonal.
PERISTOME (MOUTH): Size: Large; diameter 48% of test diameter. Shape: Slightly oval. Lip: Equally spaced buccal notches.
SPINES: Unknown.
SPECIMENS STUDIED & CONDITION: One specimen studied from the Collection of Ed Elliott.
ETYMOLOGY
Named for Comal County, Texas, where the type specimens were collected (Whitney & Kellum, 1966).
REMARKS & COMPARISONS
Remarks: Originally described as Orthopsis comalensis by Whitney & Kellum (1966). Orthopsis is characterized by perforate tubercles. Smith & Rader (2009) re-examined the taxon and determined the tubercles are imperforate, necessitating reassignment to the genus Parorthopsis. This is a critical distinction, as imperforate tubercles exclude it from the Orthopsidae.
