Craginaster completa (Cragin, 1892)
Plate: CrCr-10
Series: Lower Cretaceous Group: Washita Formation: Grayson
Locale: Denton County: Denton Stage: Cenomanian
Length: 41.7 mm Width: 36.9 mm Height: 33.3 mm
Specimen in photo: Collection of Ed Elliott
Repository: Private Collection
HOLOTYPE INFO:
Holotype: NPL (Presumed, based on Cragin collection at UT Austin).
Locality: Denton County, Texas (Cragin, 1893).
SYNONYMY
Class: Echinoidea Leske, 1778
Subclass: Euechinoidea Bronn, 1860
Infraclass: Irregularia Latreille, 1825
Superorder: Atelostomata Zittel, 1879
Order: Holasteroida Durham & Melville, 1957
Family: Holasteridae Pictet, 1857
Genus: CRAGINASTER Lambert, 1903
Species: Craginaster completa (Cragin, 1892)
TYPE SPECIES: Holaster completus Cragin, 1892
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Washita
Formations: Grayson Marl (Cragin, 1893)
Stratigraphic Units: Lower Cretaceous, Cenomanian
Counties: Denton
DESCRIPTION
TOP: Length, width, height: 41.7 mm L × 36.9 mm W × 33.3 mm H . Cragin (1893) Example 1: 48 mm L x 44 mm W x 35.5 mm H.
Top shape: Ovate; pointed posteriorly; not anteriorly emarginate (Cragin, 1893)
Top domed: Summit region flattish-convex (Cragin, 1893)
SIDE: Ambitus: About 40% from adoral side
Side shape: Very inflated, globular; lateral walls high and subvertical but slightly convex; posterior end truncated (Cragin, 1893)
BOTTOM: Bottom flat: Somewhat flat, but convex ; Inferior surface convex (Cragin, 1893)
AMB: Amb shape: Lanceolate
Amb arrangement: Unpaired ambulacrum not occupying a furrow; about as conspicuous as the others. Paired ambs run to about midpoint down sides (Cragin, 1893; Thompson, 2016)
PORE PAIRS: Inner row dot-like (round); outer row elongate/cuneate-slit-like. Rows converge down lateral wall, meeting on lower part to form single row of dot-like pores, Density variation: About 1/4th from top, spacing increases and pores get smaller/shorter
TUBERCLES: Primary tubercles: Perforated, sparse; larger adorally
Primary Areola shape: Sunken
Secondary tubercles: Tubercles surrounded by simple or sometimes partly double rings of granules (Cragin, 1893)
Arrangement: Pores on circumpolar part of ambulacra subtended by compressed tubercles forming an imperfect star-like pattern (Cragin, 1893)
APICAL SYSTEM: Size / Location: Slightly anterior of center
Shape: Oblong; shorter and broader than Holaster simplex. Bilaterally symmetrical (Cragin, 1893)
Madreporite: Shared by the four genitals and two intermediate oculars (Cragin, 1893)
PERIPROCT (ANUS): Shape & Size: Longitudinally ovate/teardrop; pointed above (adapically) (Cragin, 1893)
Location: On posterior truncation below ambitus; about 22% from adoral surface
Visibility: Cannot be seen from above
PERISTOME (MOUTH): Shape: Transversely subreniform (kidney-shaped) (Cragin, 1893); Pentagonal
Lip: Posterior lip protruding (Cragin, 1893)
Visibility: Can be seen from end
SPECIMENS STUDIED & CONDITION: Specimen CoCr-10 from Ed Elliott Collection .
ETYMOLOGY: From the Latin completus ("complete"). Cragin likely referred to the "complete" participation of all genital and ocular plates in the madreporite, which he noted as a key distinction.
REMARKS & COMPARISONS
Remarks: Craginaster was established by Lambert (1903) specifically for Holaster completus based on the unique apical system where the madreporite extends across the genitals and oculars. Cragin (1893) noted this "madreporite function... being shared" as a key distinction from Holaster simplex.
Comparisons: Differs from Holaster simplex by the apical system structure, lack of a deep anterior furrow (test is not emarginate), and more globular/subcylindrical shape (Cragin, 1893).
Plate: CrCr-10
Series: Lower Cretaceous Group: Washita Formation: Grayson
Locale: Denton County: Denton Stage: Cenomanian
Length: 41.7 mm Width: 36.9 mm Height: 33.3 mm
Specimen in photo: Collection of Ed Elliott
Repository: Private Collection
HOLOTYPE INFO:
Holotype: NPL (Presumed, based on Cragin collection at UT Austin).
Locality: Denton County, Texas (Cragin, 1893).
SYNONYMY
- Holaster completus Cragin, 1892
- Pseudananchys completa (Cragin, 1892)
Class: Echinoidea Leske, 1778
Subclass: Euechinoidea Bronn, 1860
Infraclass: Irregularia Latreille, 1825
Superorder: Atelostomata Zittel, 1879
Order: Holasteroida Durham & Melville, 1957
Family: Holasteridae Pictet, 1857
Genus: CRAGINASTER Lambert, 1903
Species: Craginaster completa (Cragin, 1892)
TYPE SPECIES: Holaster completus Cragin, 1892
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Washita
Formations: Grayson Marl (Cragin, 1893)
Stratigraphic Units: Lower Cretaceous, Cenomanian
Counties: Denton
DESCRIPTION
TOP: Length, width, height: 41.7 mm L × 36.9 mm W × 33.3 mm H . Cragin (1893) Example 1: 48 mm L x 44 mm W x 35.5 mm H.
Top shape: Ovate; pointed posteriorly; not anteriorly emarginate (Cragin, 1893)
Top domed: Summit region flattish-convex (Cragin, 1893)
SIDE: Ambitus: About 40% from adoral side
Side shape: Very inflated, globular; lateral walls high and subvertical but slightly convex; posterior end truncated (Cragin, 1893)
BOTTOM: Bottom flat: Somewhat flat, but convex ; Inferior surface convex (Cragin, 1893)
AMB: Amb shape: Lanceolate
Amb arrangement: Unpaired ambulacrum not occupying a furrow; about as conspicuous as the others. Paired ambs run to about midpoint down sides (Cragin, 1893; Thompson, 2016)
PORE PAIRS: Inner row dot-like (round); outer row elongate/cuneate-slit-like. Rows converge down lateral wall, meeting on lower part to form single row of dot-like pores, Density variation: About 1/4th from top, spacing increases and pores get smaller/shorter
TUBERCLES: Primary tubercles: Perforated, sparse; larger adorally
Primary Areola shape: Sunken
Secondary tubercles: Tubercles surrounded by simple or sometimes partly double rings of granules (Cragin, 1893)
Arrangement: Pores on circumpolar part of ambulacra subtended by compressed tubercles forming an imperfect star-like pattern (Cragin, 1893)
APICAL SYSTEM: Size / Location: Slightly anterior of center
Shape: Oblong; shorter and broader than Holaster simplex. Bilaterally symmetrical (Cragin, 1893)
Madreporite: Shared by the four genitals and two intermediate oculars (Cragin, 1893)
PERIPROCT (ANUS): Shape & Size: Longitudinally ovate/teardrop; pointed above (adapically) (Cragin, 1893)
Location: On posterior truncation below ambitus; about 22% from adoral surface
Visibility: Cannot be seen from above
PERISTOME (MOUTH): Shape: Transversely subreniform (kidney-shaped) (Cragin, 1893); Pentagonal
Lip: Posterior lip protruding (Cragin, 1893)
Visibility: Can be seen from end
SPECIMENS STUDIED & CONDITION: Specimen CoCr-10 from Ed Elliott Collection .
ETYMOLOGY: From the Latin completus ("complete"). Cragin likely referred to the "complete" participation of all genital and ocular plates in the madreporite, which he noted as a key distinction.
REMARKS & COMPARISONS
Remarks: Craginaster was established by Lambert (1903) specifically for Holaster completus based on the unique apical system where the madreporite extends across the genitals and oculars. Cragin (1893) noted this "madreporite function... being shared" as a key distinction from Holaster simplex.
Comparisons: Differs from Holaster simplex by the apical system structure, lack of a deep anterior furrow (test is not emarginate), and more globular/subcylindrical shape (Cragin, 1893).
