Undetermined Genus #2
Plate: UnGe-20
Series: Upper Cretaceous Group: Navarro Formation: Kemp Clay
Locale: Webberville County: Travis Stage: Maastrichtian
Length: 0.7 mm (estimate) Height: 0.4 mm (estimate)
Specimen in photos: Collection of Chris Garvie
Juvenile. Micro.
Repository: Private Collection
FIGURED SPECIMEN INFO:
Specimen: Collection of Chris Garvie.
Locality: Webberville, Travis County, Texas.
Stratigraphy: Kemp Clay, Navarro Group.
SYSTEMATIC PALEONTOLOGY – TAXONOMY
Class: Echinoidea Leske, 1778
Order: Unknown; possibly Salenioida
Family: (Unknown)
Genus: Undetermined
Species: Undetermined sp.
DIAGNOSIS
A microscopic, globular echinoid test. Characterized by wide ambulacra with large biserial pores and a large, triangular periproct offset to one side of the apical system.
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Navarro
Formations: Kemp Clay.
Stratigraphic Units: Upper Cretaceous, Maastrichtian.
Counties: Travis.
Abundance: Rare; one micro-specimen studied.
DESCRIPTION
TOP: Length, width, height: 0.7 mm L × 0.4 mm H. Top shape: (Implied round/globular).
SIDE: Side shape: Globular.
BOTTOM: (Not specified).
AMB: Amb shape: Wide; just slightly narrower than interambulacra.
PORE PAIRS: Arrangement: Large biserial pores.
TUBERCLES: Condition: Difficult to describe due to micro size.
GRANULES: (Unknown).
FASCIOLE: (Unknown).
APICAL SYSTEM: Size: Round; occupies just over 1/4 (25%) the width of the test.
PERIPROCT (ANUS): Shape: Large and triangular. Location: Offset on one side of the apical system.
PERISTOME (MOUTH): Shape: Round. Size: Just slightly smaller than the apical system.
SPINES: Unknown.
SPECIMENS STUDIED & CONDITION: One juvenile/micro specimen from the Collection of Chris Garvie.
REMARKS & COMPARISONS
Remarks: This specimen is a juvenile micro-echinoid. The morphology of the periproct ("large triangular... offset on one side of apical system") strongly suggests an affinity with the Saleniidae (Salenioida), where the suranal plate displaces the periproct to the side (usually toward Ocular I). However, the description of "biserial pores" is unusual for a juvenile saleniid, which typically has uniserial pores.
Plate: UnGe-20
Series: Upper Cretaceous Group: Navarro Formation: Kemp Clay
Locale: Webberville County: Travis Stage: Maastrichtian
Length: 0.7 mm (estimate) Height: 0.4 mm (estimate)
Specimen in photos: Collection of Chris Garvie
Juvenile. Micro.
Repository: Private Collection
FIGURED SPECIMEN INFO:
Specimen: Collection of Chris Garvie.
Locality: Webberville, Travis County, Texas.
Stratigraphy: Kemp Clay, Navarro Group.
SYSTEMATIC PALEONTOLOGY – TAXONOMY
Class: Echinoidea Leske, 1778
Order: Unknown; possibly Salenioida
Family: (Unknown)
Genus: Undetermined
Species: Undetermined sp.
DIAGNOSIS
A microscopic, globular echinoid test. Characterized by wide ambulacra with large biserial pores and a large, triangular periproct offset to one side of the apical system.
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Navarro
Formations: Kemp Clay.
Stratigraphic Units: Upper Cretaceous, Maastrichtian.
Counties: Travis.
Abundance: Rare; one micro-specimen studied.
DESCRIPTION
TOP: Length, width, height: 0.7 mm L × 0.4 mm H. Top shape: (Implied round/globular).
SIDE: Side shape: Globular.
BOTTOM: (Not specified).
AMB: Amb shape: Wide; just slightly narrower than interambulacra.
PORE PAIRS: Arrangement: Large biserial pores.
TUBERCLES: Condition: Difficult to describe due to micro size.
GRANULES: (Unknown).
FASCIOLE: (Unknown).
APICAL SYSTEM: Size: Round; occupies just over 1/4 (25%) the width of the test.
PERIPROCT (ANUS): Shape: Large and triangular. Location: Offset on one side of the apical system.
PERISTOME (MOUTH): Shape: Round. Size: Just slightly smaller than the apical system.
SPINES: Unknown.
SPECIMENS STUDIED & CONDITION: One juvenile/micro specimen from the Collection of Chris Garvie.
REMARKS & COMPARISONS
Remarks: This specimen is a juvenile micro-echinoid. The morphology of the periproct ("large triangular... offset on one side of apical system") strongly suggests an affinity with the Saleniidae (Salenioida), where the suranal plate displaces the periproct to the side (usually toward Ocular I). However, the description of "biserial pores" is unusual for a juvenile saleniid, which typically has uniserial pores.
