Plegiocidaris pawpawensis Thompson, 2016
Plate: PlPa-10
Series: Lower Cretaceous Group: Washita Formation: Pawpaw
Locale: Rio Vista County: Johnson Stage: Albian
Width: 30.4 mm Height: 9.8 mm
Specimen in photo: NPL 83044 Holotype
Collector: Stephen Crane
Repository: Non-vertebrate Paleo. Lab., Univ. of Texas Spine.
HOLOTYPE INFO:
Holotype: NPL 83044 .
Locality: Rio Vista, Johnson County, Texas.
Stratigraphy: Pawpaw Formation, Washita Group.
SYSTEMATIC PALEONTOLOGY – TAXONOMY
Class: Echinoidea Leske, 1778
Subclass: Cidaroidea Smith, 1984
Order: Cidaroida Claus, 1880
Family: Cidaridae Gray, 1825
Genus: PLEGIOCIDARIS Pomel, 1883
Species: Plegiocidaris pawpawensis Thompson, 2016
TYPE SPECIES: Echinus coronatus Schlotheim, 1820
DIAGNOSIS
Species defined by a thick, club-shaped spine found in the Pawpaw Formation. The shaft is ornamented with dense, beaded rows.
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Washita
Formations: Pawpaw Formation.
Stratigraphic Units: Lower Cretaceous, Albian.
Counties: Johnson.
Abundance: Rare.
DESCRIPTION
SPINES: Shape: Thick and club-shaped. Distal end is somewhat pointed; neck end is missing in the holotype. Ornamentation: Shaft is composed of dense, beaded rows.
SPECIMENS STUDIED & CONDITION: Holotype NPL 83044 (Isolated spine).
ETYMOLOGY
Named after the Pawpaw Formation, the stratigraphic unit where the fossil was found.
REMARKS & COMPARISONS
Remarks: This species represents a rare Cretaceous occurrence of Plegiocidaris, a genus more commonly associated with the Jurassic. It is distinguished from other species by the pointed distal end of the spine, whereas most spines in the genus have more rounded ends.
Plate: PlPa-10
Series: Lower Cretaceous Group: Washita Formation: Pawpaw
Locale: Rio Vista County: Johnson Stage: Albian
Width: 30.4 mm Height: 9.8 mm
Specimen in photo: NPL 83044 Holotype
Collector: Stephen Crane
Repository: Non-vertebrate Paleo. Lab., Univ. of Texas Spine.
HOLOTYPE INFO:
Holotype: NPL 83044 .
Locality: Rio Vista, Johnson County, Texas.
Stratigraphy: Pawpaw Formation, Washita Group.
SYSTEMATIC PALEONTOLOGY – TAXONOMY
Class: Echinoidea Leske, 1778
Subclass: Cidaroidea Smith, 1984
Order: Cidaroida Claus, 1880
Family: Cidaridae Gray, 1825
Genus: PLEGIOCIDARIS Pomel, 1883
Species: Plegiocidaris pawpawensis Thompson, 2016
TYPE SPECIES: Echinus coronatus Schlotheim, 1820
DIAGNOSIS
Species defined by a thick, club-shaped spine found in the Pawpaw Formation. The shaft is ornamented with dense, beaded rows.
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Washita
Formations: Pawpaw Formation.
Stratigraphic Units: Lower Cretaceous, Albian.
Counties: Johnson.
Abundance: Rare.
DESCRIPTION
SPINES: Shape: Thick and club-shaped. Distal end is somewhat pointed; neck end is missing in the holotype. Ornamentation: Shaft is composed of dense, beaded rows.
SPECIMENS STUDIED & CONDITION: Holotype NPL 83044 (Isolated spine).
ETYMOLOGY
Named after the Pawpaw Formation, the stratigraphic unit where the fossil was found.
REMARKS & COMPARISONS
Remarks: This species represents a rare Cretaceous occurrence of Plegiocidaris, a genus more commonly associated with the Jurassic. It is distinguished from other species by the pointed distal end of the spine, whereas most spines in the genus have more rounded ends.
