Echinopygus lampas (de la Beche, 1833)
Plate: EcLa-10
Series: Lower Cretaceous Group: Fredericksburg Formation: Comanche Peak
Locale: Unsure County: Callahan Stage: Albian
Length: 70.6 mm Width: 58.6 mm Height: 33.9 mm
Specimen in photo: Collection of Stephen Crane
Repository: Private Collection
HOLOTYPE INFO:
Lectotype: Specimen figured by De la Beche (1833); housed in the École des Mines, Paris (Kier, 1962)
Locality: Lyme Regis, England (De la Beche, 1833; Kier, 1962)
Stratigraphy: Cretaceous (Cenomanian) greensand (Kier, 1962)
SYNONYMY
SYSTEMATIC PALEONTOLOGY – TAXONOMY
Class: Echinoidea Leske, 1778
Subclass: Euechinoidea Bronn, 1860
Infraclass: Irregularia Latreille, 1825
Superorder: Neognathostomata Smith, 1981
Order: Cassiduloida Claus, 1880
Family: Pyguridae Lambert, 1898
Genus: ECHINOPYGUS d'Orbigny, 1856
Species: Echinopygus lampas (de la Beche, 1833)
TYPE SPECIES: Echinopygus lampas (de la Beche, 1833)
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Fredericksburg
Formations: Comanche Peak Formation
Stratigraphic Units: Lower Cretaceous, Albian ; Cenomanian in Europe (Kier, 1962)
Counties: Callahan County
DESCRIPTION
TOP: Length, width, height: 70.6 mm L × 58.6 mm W × 33.9 mm H ; Lectotype 74.0 mm L (Kier, 1962)
Top shape: Length greater than width; margin angular with posterior greatly prolonged (Kier, 1962)
Widest location: Posterior to center (Kier, 1962)
SIDE: Side shape: Adoral surface inflated with greatest height anterior to center at apical system; steeply sloping sides (Kier, 1962)
BOTTOM: Bottom shape: Adoral surface concave (Kier, 1962)
AMB: Amb shape: Petals broad, equal, long (extending over 2/3 distance to margin), closed; strongly tapering distally (Kier, 1962)
Amb primary zones: Poriferous zones narrow; Interporiferous zones very wide (Kier, 1962)
Phyllodes: Double pored, very broad and large; one series of pore pairs in each half-ambulacrum with wide space between series (Kier, 1962)
PORE PAIRS: Shape: Inner pores slightly elongated transversely; outer pores slit-like (Kier, 1962)
Density variation: Pore pairs widely separated from edge of peristome; no buccal pores (Kier, 1962)
TUBERCLES: Primary tubercles: Tubercles on adoral surface larger than those on adapical surface (Kier, 1962)
APICAL SYSTEM: Location: Anterior to center (at greatest height) (Kier, 1962). Unfortunately, the apical system is missing.
PERIPROCT (ANUS): Shape & Size: Tear-drop shaped, with apex pointing adorally; width approximately equal to length (Kier, 1962)
Location: Inframarginal; on slight oblique truncation (Kier, 1962)
PERISTOME (MOUTH): Shape: Pentagonal; slightly higher than wide (Kier, 1962)
Location: Anterior (Kier, 1962)
Lip: Bourrelets strongly developed, tooth-like; deeply depressed between bourrelets (Kier, 1962)
PHYLLODES: Phyllode Arrangement: Advanced biserial (pseudotriserial).
SPECIMENS STUDIED & CONDITION: Specimen EcLa-10 in Stephen Crane Collection. Kier (1962) studied three specimens in the École des Mines, Paris, designating one as Lectotype.
ETYMOLOGY: From the Greek/Latin lampas, meaning "torch" or "lamp," referencing the shape characteristic of cassiduloids (often called "lamp urchins").
REMARKS & COMPARISONS
Remarks: d'Orbigny distinguished Echinopygus from Pygurus based on the periproct being transverse in Echinopygus but longitudinal in Pygurus. Kier (1962) noted that in P. lampas, the periproct width is approximately equal to the length, and argued it should be considered congeneric with Pygurus. The user retains the genus Echinopygus for the Texas specimen.
Comparisons: Differentiated from Pygurus rostratus where the periproct is definitely wider than high (Kier, 1962).
Plate: EcLa-10
Series: Lower Cretaceous Group: Fredericksburg Formation: Comanche Peak
Locale: Unsure County: Callahan Stage: Albian
Length: 70.6 mm Width: 58.6 mm Height: 33.9 mm
Specimen in photo: Collection of Stephen Crane
Repository: Private Collection
HOLOTYPE INFO:
Lectotype: Specimen figured by De la Beche (1833); housed in the École des Mines, Paris (Kier, 1962)
Locality: Lyme Regis, England (De la Beche, 1833; Kier, 1962)
Stratigraphy: Cretaceous (Cenomanian) greensand (Kier, 1962)
SYNONYMY
- Echinois lampas De la Beche, 1833
- Pygurus (Pygurus) lampas (De la Beche, 1833) (Kier, 1962)
- Pygurus (Pygitrits) lampas (d'Orbigny)
SYSTEMATIC PALEONTOLOGY – TAXONOMY
Class: Echinoidea Leske, 1778
Subclass: Euechinoidea Bronn, 1860
Infraclass: Irregularia Latreille, 1825
Superorder: Neognathostomata Smith, 1981
Order: Cassiduloida Claus, 1880
Family: Pyguridae Lambert, 1898
Genus: ECHINOPYGUS d'Orbigny, 1856
Species: Echinopygus lampas (de la Beche, 1833)
TYPE SPECIES: Echinopygus lampas (de la Beche, 1833)
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Fredericksburg
Formations: Comanche Peak Formation
Stratigraphic Units: Lower Cretaceous, Albian ; Cenomanian in Europe (Kier, 1962)
Counties: Callahan County
DESCRIPTION
TOP: Length, width, height: 70.6 mm L × 58.6 mm W × 33.9 mm H ; Lectotype 74.0 mm L (Kier, 1962)
Top shape: Length greater than width; margin angular with posterior greatly prolonged (Kier, 1962)
Widest location: Posterior to center (Kier, 1962)
SIDE: Side shape: Adoral surface inflated with greatest height anterior to center at apical system; steeply sloping sides (Kier, 1962)
BOTTOM: Bottom shape: Adoral surface concave (Kier, 1962)
AMB: Amb shape: Petals broad, equal, long (extending over 2/3 distance to margin), closed; strongly tapering distally (Kier, 1962)
Amb primary zones: Poriferous zones narrow; Interporiferous zones very wide (Kier, 1962)
Phyllodes: Double pored, very broad and large; one series of pore pairs in each half-ambulacrum with wide space between series (Kier, 1962)
PORE PAIRS: Shape: Inner pores slightly elongated transversely; outer pores slit-like (Kier, 1962)
Density variation: Pore pairs widely separated from edge of peristome; no buccal pores (Kier, 1962)
TUBERCLES: Primary tubercles: Tubercles on adoral surface larger than those on adapical surface (Kier, 1962)
APICAL SYSTEM: Location: Anterior to center (at greatest height) (Kier, 1962). Unfortunately, the apical system is missing.
PERIPROCT (ANUS): Shape & Size: Tear-drop shaped, with apex pointing adorally; width approximately equal to length (Kier, 1962)
Location: Inframarginal; on slight oblique truncation (Kier, 1962)
PERISTOME (MOUTH): Shape: Pentagonal; slightly higher than wide (Kier, 1962)
Location: Anterior (Kier, 1962)
Lip: Bourrelets strongly developed, tooth-like; deeply depressed between bourrelets (Kier, 1962)
PHYLLODES: Phyllode Arrangement: Advanced biserial (pseudotriserial).
SPECIMENS STUDIED & CONDITION: Specimen EcLa-10 in Stephen Crane Collection. Kier (1962) studied three specimens in the École des Mines, Paris, designating one as Lectotype.
ETYMOLOGY: From the Greek/Latin lampas, meaning "torch" or "lamp," referencing the shape characteristic of cassiduloids (often called "lamp urchins").
REMARKS & COMPARISONS
Remarks: d'Orbigny distinguished Echinopygus from Pygurus based on the periproct being transverse in Echinopygus but longitudinal in Pygurus. Kier (1962) noted that in P. lampas, the periproct width is approximately equal to the length, and argued it should be considered congeneric with Pygurus. The user retains the genus Echinopygus for the Texas specimen.
Comparisons: Differentiated from Pygurus rostratus where the periproct is definitely wider than high (Kier, 1962).
