Holaster nodulosus Goldfuss, 1829
Plate: HoNo-10
Series: Lower Cretaceous Group: Washita Formation: Weno
Locale: County: Stage: Albian
Length: 47.5 mm Width: 41.6 mm Height: 25.1 mm
Specimen in photo: Collection of Chris Garvie (The Akers Collection)
Repository: Private Collection
HOLOTYPE INFO:
Holotype: Goldfuss Collection, University of Bonn, Germany.
Locality: Westphalia, Germany (Goldfuss, 1829).
Stratigraphy: Cenomanian (Green Sand).
SYNONYMY
Class: Echinoidea Leske, 1778
Subclass: Euechinoidea Bronn, 1860
Infraclass: Irregularia Latreille, 1825
Superorder: Atelostomata Zittel, 1879
Order: Holasteroida Durham, 1957
Family: Holasteridae Pictet, 1857
Genus: HOLASTER L. Agassiz, 1836
Species: Holaster nodulosus (Goldfuss, 1829)
TYPE SPECIES: Spatangus nodulosus Goldfuss, 1829
DIAGNOSIS
Test cordate, inflated, and strongly arched; posterior surface vertically truncated. Anterior sulcus wide and shallow. Apical system elongate (intercalary). Anterior poriferous zones of paired ambulacra are narrower than the posterior zones.
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Washita
Formations: Weno Formation (Texas specimen); Cenomanian deposits of Europe (Type).
Stratigraphic Units: Lower Cretaceous, Albian (Texas); Upper Cretaceous, Cenomanian (Europe).
Counties: Not Specified
Abundance: Rare in Texas; common in the Cenomanian of Europe.
DESCRIPTION
TOP: Length, width, height: 47.5 mm L × 41.6 mm W × 25.1 mm H.
Top shape: Heart-shaped (cordate) with a shallow frontal sulcus (Cooke, 1955).
Top domed: Upper surface strongly arched (Cooke, 1955).
SIDE: Side shape: Rounded sides (Cooke, 1955). Posterior face vertically truncated (d'Orbigny, 1853).
Profile: Somewhat rostrate (beaked/arched) above the terminal periproct (Cooke, 1955).
BOTTOM: Bottom shape: Slightly convex lower surface (Cooke, 1955).
AMB: Amb shape: Paired ambulacra are subpetaloid, flush, and open distally.
Amb arrangement: The anterior poriferous zones are narrower than the posterior zones in the paired ambulacra (Cooke, 1955).
PORE PAIRS: Shape: Pores of the paired ambulacra are transversely elongated (Cooke, 1955).
Arrangement: The unpaired anterior ambulacrum consists of small, round, oblique pores (d'Orbigny, 1853).
TUBERCLES: Distribution: Tubercles are fine and scattered on the aboral surface, becoming larger and more dense on the oral surface and plastron.
Ornamentation: In the type description, Goldfuss noted a "nodulose" appearance, often referring to the coarse tuberculation or preservation on the plastron.
GRANULES: Not specified.
FASCIOLE: Absent in Holaster.
APICAL SYSTEM: Shape: Elongated (Cooke, 1955).
Plating: Intercalary type; the genital plates are separated by ocular plates meeting in the midline (d'Orbigny, 1853).
PERIPROCT (ANUS): Shape: Longer than wide (Cooke, 1955); oval and vertically elongate (d'Orbigny, 1853).
Location: High on the posterior truncation; visible from the posterior view.
PERISTOME (MOUTH): Shape: Transversely elliptical (Cooke, 1955).
Location: Anterior, near the margin.
SPINES: Unknown.
SPECIMENS STUDIED & CONDITION: One specimen studied from the Collection of Chris Garvie (The Akers Collection).
ETYMOLOGY
From the Latin nodulosus (having little knots or nodules), referring to the texture of the test surface or plastron in the type specimens.
REMARKS & COMPARISONS
Remarks: Holaster nodulosus is the type species of the genus. While it is a common index fossil in the Cenomanian of Europe (France, Germany), its occurrence in the Albian (Weno Formation) of Texas is unusual. Texas specimens are more commonly assigned to H. simplex or H. laevis. The specimen described here is assigned to H. nodulosus based on the Akers/Garvie collection identification.
Comparisons:
Plate: HoNo-10
Series: Lower Cretaceous Group: Washita Formation: Weno
Locale: County: Stage: Albian
Length: 47.5 mm Width: 41.6 mm Height: 25.1 mm
Specimen in photo: Collection of Chris Garvie (The Akers Collection)
Repository: Private Collection
HOLOTYPE INFO:
Holotype: Goldfuss Collection, University of Bonn, Germany.
Locality: Westphalia, Germany (Goldfuss, 1829).
Stratigraphy: Cenomanian (Green Sand).
SYNONYMY
- Spatangus nodulosus Goldfuss, 1829
- Holaster suborbicularis Agassiz, 1847
Class: Echinoidea Leske, 1778
Subclass: Euechinoidea Bronn, 1860
Infraclass: Irregularia Latreille, 1825
Superorder: Atelostomata Zittel, 1879
Order: Holasteroida Durham, 1957
Family: Holasteridae Pictet, 1857
Genus: HOLASTER L. Agassiz, 1836
Species: Holaster nodulosus (Goldfuss, 1829)
TYPE SPECIES: Spatangus nodulosus Goldfuss, 1829
DIAGNOSIS
Test cordate, inflated, and strongly arched; posterior surface vertically truncated. Anterior sulcus wide and shallow. Apical system elongate (intercalary). Anterior poriferous zones of paired ambulacra are narrower than the posterior zones.
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Washita
Formations: Weno Formation (Texas specimen); Cenomanian deposits of Europe (Type).
Stratigraphic Units: Lower Cretaceous, Albian (Texas); Upper Cretaceous, Cenomanian (Europe).
Counties: Not Specified
Abundance: Rare in Texas; common in the Cenomanian of Europe.
DESCRIPTION
TOP: Length, width, height: 47.5 mm L × 41.6 mm W × 25.1 mm H.
Top shape: Heart-shaped (cordate) with a shallow frontal sulcus (Cooke, 1955).
Top domed: Upper surface strongly arched (Cooke, 1955).
SIDE: Side shape: Rounded sides (Cooke, 1955). Posterior face vertically truncated (d'Orbigny, 1853).
Profile: Somewhat rostrate (beaked/arched) above the terminal periproct (Cooke, 1955).
BOTTOM: Bottom shape: Slightly convex lower surface (Cooke, 1955).
AMB: Amb shape: Paired ambulacra are subpetaloid, flush, and open distally.
Amb arrangement: The anterior poriferous zones are narrower than the posterior zones in the paired ambulacra (Cooke, 1955).
PORE PAIRS: Shape: Pores of the paired ambulacra are transversely elongated (Cooke, 1955).
Arrangement: The unpaired anterior ambulacrum consists of small, round, oblique pores (d'Orbigny, 1853).
TUBERCLES: Distribution: Tubercles are fine and scattered on the aboral surface, becoming larger and more dense on the oral surface and plastron.
Ornamentation: In the type description, Goldfuss noted a "nodulose" appearance, often referring to the coarse tuberculation or preservation on the plastron.
GRANULES: Not specified.
FASCIOLE: Absent in Holaster.
APICAL SYSTEM: Shape: Elongated (Cooke, 1955).
Plating: Intercalary type; the genital plates are separated by ocular plates meeting in the midline (d'Orbigny, 1853).
PERIPROCT (ANUS): Shape: Longer than wide (Cooke, 1955); oval and vertically elongate (d'Orbigny, 1853).
Location: High on the posterior truncation; visible from the posterior view.
PERISTOME (MOUTH): Shape: Transversely elliptical (Cooke, 1955).
Location: Anterior, near the margin.
SPINES: Unknown.
SPECIMENS STUDIED & CONDITION: One specimen studied from the Collection of Chris Garvie (The Akers Collection).
ETYMOLOGY
From the Latin nodulosus (having little knots or nodules), referring to the texture of the test surface or plastron in the type specimens.
REMARKS & COMPARISONS
Remarks: Holaster nodulosus is the type species of the genus. While it is a common index fossil in the Cenomanian of Europe (France, Germany), its occurrence in the Albian (Weno Formation) of Texas is unusual. Texas specimens are more commonly assigned to H. simplex or H. laevis. The specimen described here is assigned to H. nodulosus based on the Akers/Garvie collection identification.
Comparisons:
- H. simplex: H. nodulosus generally possesses a more defined anterior sulcus and a more vertically truncated posterior than the variable H. simplex.
