Cibaster texanus Thompson, 2016
Plate: CiTe-10
Series: Upper Cretaceous Group: Austin? – Taylor? Formation: Uncertain
Locale: Austin County: Travis Stage: Campanian? Santonian?
Length: 30.2 mm Width: 28.6 mm Height: 18.0 mm
Specimen in photo: NPL 70924 (Holotype)
Repository: Non-vertebrate Paleo. Lab., Univ. of Texas
HOLOTYPE INFO:
Holotype: NPL 70924 — Non-vertebrate Paleontology Laboratory, University of Texas
Locality: Quarry in southeast Austin, Travis County, Texas
Systematic Paleontology
CLASS: ECHINOIDEA Leske, 1778
SUBCLASS: EUECHINOIDEA Bronn, 1860
INFRACLASS: IRREGULARIA Latreille, 1825
SUPERORDER: ATELOSTOMATA Zittel, 1879
ORDER: HOLASTEROIDA Durham & Melville, 1957
SUBORDER: MERIDOSTERNATA Lovén, 1883
FAMILY: HOLASTERIDAE Pictet, 1857
GENUS: CIBASTER Pomel, 1883
SPECIES: Cibaster texanus Thompson, 2016
TYPE SPECIES: Cardiaster bourgeoisanus d'Orbigny, 1853
DIAGNOSIS: A species of Cibaster with elongated pore pairs, reniform shape peristome, pronounced periproctal sulcus.
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Austin? / Taylor?
Formations: Uncertain (Austin Chalk / Taylor Marl contact)
Stratigraphic Units: Upper Cretaceous, Santonian? / Campanian?
Counties: Travis County
DESCRIPTION
TOP: Length, width, height: 30.2 mm × 28.6 mm × 18.0 mm
Top shape: Ovate; slightly flattened anteriorly, cut at margin posteriorly at periproct
Top domed: Inflated on top
Convexity: Very curved from either side
SIDE: Ambitus: Widest at midpoint
Side shape: Ovate but more block-shaped; truncated on posterior end
BOTTOM: Bottom shape: Curved on bottom
AMB: Amb shape: All ambulacra flush, not sunken; unpaired amb very faint
Amb primary zones: Anterior paired ambs curved upward, equal in length to posterior pair; anterior reach margin, posterior do not
Petals: Broadly open; top pore sets of anterior ambs not touching bottom pairs; top set straight, bottom set curved (petaloid)
INTERAMB: Interamb primary tubercles: Largest tubercles located near top on either side of unpaired amb
PORE PAIRS: Shape: Elongated; bottom ones of bottom set more elongated
Density variation: Very small, very close to each other, sparse
Arrangement: Oblique angle
TUBERCLES: Primary Perforated: No (Implied by "non-crenulate" and Holasterid definition)
Primary Crenulate: No
Primary Areola shape: Sunken
Primary tubercles: Small, very sparse; largest near top on either side of unpaired amb
Secondary tubercles: Sparse on bottom; mostly at top margins, near peristome, and on plastron
GRANULES: Granules pattern: Faint granulation
APICAL SYSTEM: Size / Location: Anterior of center
Genital pores: 4 gonopores
PERIPROCT (ANUS): Shape & Size: Vertically oval
Location: Halfway up side at margin; cuts into edge of test
Sulcus: Pronounced periproctal sulcus
PERISTOME (MOUTH): Shape: Oval; reniform (kidney-shaped); droops downward on either end
Location: Halfway from center to anterior
Size: Narrow
SPECIMENS STUDIED & CONDITION
Specimen condition: Holotype NPL 70924 .
ETYMOLOGY: The name reflects the locality of the holotype, Texas.
REMARKS & COMPARISONS
Remarks: This is the first Cibaster described from North America.
Comparisons: Distinguished from European species C. bourgeoisanus and C. leymeriei by having larger tubercles surrounding the unpaired amb and elongated pore pairs. The peristome has a more pronounced reniform shape and is narrower. The periproctal sulcus is more pronounced than in C. bourgeoisanus or C. leymeriei. It is less inflated than C. leymeriei .
Plate: CiTe-10
Series: Upper Cretaceous Group: Austin? – Taylor? Formation: Uncertain
Locale: Austin County: Travis Stage: Campanian? Santonian?
Length: 30.2 mm Width: 28.6 mm Height: 18.0 mm
Specimen in photo: NPL 70924 (Holotype)
Repository: Non-vertebrate Paleo. Lab., Univ. of Texas
HOLOTYPE INFO:
Holotype: NPL 70924 — Non-vertebrate Paleontology Laboratory, University of Texas
Locality: Quarry in southeast Austin, Travis County, Texas
Systematic Paleontology
CLASS: ECHINOIDEA Leske, 1778
SUBCLASS: EUECHINOIDEA Bronn, 1860
INFRACLASS: IRREGULARIA Latreille, 1825
SUPERORDER: ATELOSTOMATA Zittel, 1879
ORDER: HOLASTEROIDA Durham & Melville, 1957
SUBORDER: MERIDOSTERNATA Lovén, 1883
FAMILY: HOLASTERIDAE Pictet, 1857
GENUS: CIBASTER Pomel, 1883
SPECIES: Cibaster texanus Thompson, 2016
TYPE SPECIES: Cardiaster bourgeoisanus d'Orbigny, 1853
DIAGNOSIS: A species of Cibaster with elongated pore pairs, reniform shape peristome, pronounced periproctal sulcus.
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Austin? / Taylor?
Formations: Uncertain (Austin Chalk / Taylor Marl contact)
Stratigraphic Units: Upper Cretaceous, Santonian? / Campanian?
Counties: Travis County
DESCRIPTION
TOP: Length, width, height: 30.2 mm × 28.6 mm × 18.0 mm
Top shape: Ovate; slightly flattened anteriorly, cut at margin posteriorly at periproct
Top domed: Inflated on top
Convexity: Very curved from either side
SIDE: Ambitus: Widest at midpoint
Side shape: Ovate but more block-shaped; truncated on posterior end
BOTTOM: Bottom shape: Curved on bottom
AMB: Amb shape: All ambulacra flush, not sunken; unpaired amb very faint
Amb primary zones: Anterior paired ambs curved upward, equal in length to posterior pair; anterior reach margin, posterior do not
Petals: Broadly open; top pore sets of anterior ambs not touching bottom pairs; top set straight, bottom set curved (petaloid)
INTERAMB: Interamb primary tubercles: Largest tubercles located near top on either side of unpaired amb
PORE PAIRS: Shape: Elongated; bottom ones of bottom set more elongated
Density variation: Very small, very close to each other, sparse
Arrangement: Oblique angle
TUBERCLES: Primary Perforated: No (Implied by "non-crenulate" and Holasterid definition)
Primary Crenulate: No
Primary Areola shape: Sunken
Primary tubercles: Small, very sparse; largest near top on either side of unpaired amb
Secondary tubercles: Sparse on bottom; mostly at top margins, near peristome, and on plastron
GRANULES: Granules pattern: Faint granulation
APICAL SYSTEM: Size / Location: Anterior of center
Genital pores: 4 gonopores
PERIPROCT (ANUS): Shape & Size: Vertically oval
Location: Halfway up side at margin; cuts into edge of test
Sulcus: Pronounced periproctal sulcus
PERISTOME (MOUTH): Shape: Oval; reniform (kidney-shaped); droops downward on either end
Location: Halfway from center to anterior
Size: Narrow
SPECIMENS STUDIED & CONDITION
Specimen condition: Holotype NPL 70924 .
ETYMOLOGY: The name reflects the locality of the holotype, Texas.
REMARKS & COMPARISONS
Remarks: This is the first Cibaster described from North America.
Comparisons: Distinguished from European species C. bourgeoisanus and C. leymeriei by having larger tubercles surrounding the unpaired amb and elongated pore pairs. The peristome has a more pronounced reniform shape and is narrower. The periproctal sulcus is more pronounced than in C. bourgeoisanus or C. leymeriei. It is less inflated than C. leymeriei .
