Heteraster adkinsi Lambert, 1927
Plate: HeAd-10
Series: Lower Cretaceous Group: Fredericksburg Formation: Kiamichi
Locale: Fort Stockton County: Pecos Stage: Albian
Length: 36.9 mm Width: 34.4 mm Height: 22.8 mm
Specimen in photo: BEG 34071 Hypotype
Repository: Non-vertebrate Paleo. Lab., Univ. of Texas
HOLOTYPE INFO:
Holotype: The type specimen was originally in the W. S. Adkins collection. Likely housed at the Bureau of Economic Geology (BEG) or NPL, University of Texas.
Locality: Fort Stockton, Pecos County, Texas (Lambert, 1927)
SYSTEMATIC PALEONTOLOGY – TAXONOMY
Class: Echinoidea Leske, 1778
Subclass: Euechinoidea Bronn, 1860
Infraclass: Irregularia Latreille, 1825
Superorder: Atelostomata Zittel, 1879
Order: Spatangoida L. Agassiz, 1840
Family: Toxasteridae Lambert, 1920
Genus: HETERASTER d'Orbigny, 1853
Species: Heteraster adkinsi Lambert, 1927
TYPE SPECIES: Spatangus oblongus Brongniart, 1821
DIAGNOSIS
Test cordate, with a very long, wide, deep anterior sulcus. Anterior paired petals flexuous; posterior petals petaloid. Pores of unpaired ambulacrum arranged in alternating lengths (heterasterid).
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Fredericksburg
Formations: Kiamichi Formation; Comanche Peak (Adkins, 1928)
Stratigraphic Units: Lower Cretaceous, Albian
Counties: Pecos County
DESCRIPTION
TOP: Length, width, height: 36.9 mm L × 34.4 mm W × 22.8 mm H
Top shape: Cordate; widest anterior of center.
Top domed: Apex central; test flat from apex to truncated posterior end.
SIDE: Side shape: Posterior end truncated; anterior end rounded.
Apex: Located at center.
BOTTOM: Bottom shape: Rounded.
AMB: Amb shape: Unpaired ambulacrum (III) very long, wide; sits in deep sulcus that cuts the margin.
Amb arrangement: Anterior paired ambulacra flexuous; twice the length of posterior ambulacra. Posterior paired ambulacra petaloid.
Amb primary zones: Petals are closed at apical system, open on ends.
Pore alternation:
Unpaired Amb: Pore pairs are sets of elongated slits that alternate repeatedly between slightly elongated to very elongated.
Anterior Paired Ambs: Anterior set of pore pairs round; posterior set very slightly elongated in one row and very elongated in other row.
Posterior Paired Ambs: Anterior set of pore pairs slightly elongated; posterior set elongated.
TUBERCLES: Primary tubercles: Largest tubercles around aboral margin and on adoral surface; evenly cover test.
Primary Areola shape: Sunken.
Primary Mamelon: Rounded.
Secondary tubercles: Scrobiculate.
Granules: Granulation covers test; more numerous nearing margin and below.
APICAL SYSTEM: Location: Posterior of center; about 40% from posterior margin.
Genital pores: Four gonopores.
PERIPROCT (ANUS): Shape & Size: Transversely oval; slight drop in middle.
Location: High on truncated posterior end; about 25% from margin.
PERISTOME (MOUTH): Shape: Rounded.
Location: Anterior; about 22% from anterior margin.
Visibility: Visible from posterior end.
SPECIMENS STUDIED & CONDITION: Hypotype BEG 34071.
ETYMOLOGY
Named in honor of Walter Scott Adkins (1890–1956), a preeminent Texas stratigrapher and paleontologist (Lambert, 1927).
REMARKS & COMPARISONS
Remarks: Miller (2009), in Preliminary Revision of Heteraster (Echinoidea) from the Lower Cretaceous of Texas, states that H. adkinsi is a synonym of Heteraster texanus (Roemer). The species is characterized by the distinct alternation of pore lengths in the unpaired ambulacrum, a hallmark of the genus Heteraster.
Plate: HeAd-10
Series: Lower Cretaceous Group: Fredericksburg Formation: Kiamichi
Locale: Fort Stockton County: Pecos Stage: Albian
Length: 36.9 mm Width: 34.4 mm Height: 22.8 mm
Specimen in photo: BEG 34071 Hypotype
Repository: Non-vertebrate Paleo. Lab., Univ. of Texas
HOLOTYPE INFO:
Holotype: The type specimen was originally in the W. S. Adkins collection. Likely housed at the Bureau of Economic Geology (BEG) or NPL, University of Texas.
Locality: Fort Stockton, Pecos County, Texas (Lambert, 1927)
SYSTEMATIC PALEONTOLOGY – TAXONOMY
Class: Echinoidea Leske, 1778
Subclass: Euechinoidea Bronn, 1860
Infraclass: Irregularia Latreille, 1825
Superorder: Atelostomata Zittel, 1879
Order: Spatangoida L. Agassiz, 1840
Family: Toxasteridae Lambert, 1920
Genus: HETERASTER d'Orbigny, 1853
Species: Heteraster adkinsi Lambert, 1927
TYPE SPECIES: Spatangus oblongus Brongniart, 1821
DIAGNOSIS
Test cordate, with a very long, wide, deep anterior sulcus. Anterior paired petals flexuous; posterior petals petaloid. Pores of unpaired ambulacrum arranged in alternating lengths (heterasterid).
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Fredericksburg
Formations: Kiamichi Formation; Comanche Peak (Adkins, 1928)
Stratigraphic Units: Lower Cretaceous, Albian
Counties: Pecos County
DESCRIPTION
TOP: Length, width, height: 36.9 mm L × 34.4 mm W × 22.8 mm H
Top shape: Cordate; widest anterior of center.
Top domed: Apex central; test flat from apex to truncated posterior end.
SIDE: Side shape: Posterior end truncated; anterior end rounded.
Apex: Located at center.
BOTTOM: Bottom shape: Rounded.
AMB: Amb shape: Unpaired ambulacrum (III) very long, wide; sits in deep sulcus that cuts the margin.
Amb arrangement: Anterior paired ambulacra flexuous; twice the length of posterior ambulacra. Posterior paired ambulacra petaloid.
Amb primary zones: Petals are closed at apical system, open on ends.
Pore alternation:
Unpaired Amb: Pore pairs are sets of elongated slits that alternate repeatedly between slightly elongated to very elongated.
Anterior Paired Ambs: Anterior set of pore pairs round; posterior set very slightly elongated in one row and very elongated in other row.
Posterior Paired Ambs: Anterior set of pore pairs slightly elongated; posterior set elongated.
TUBERCLES: Primary tubercles: Largest tubercles around aboral margin and on adoral surface; evenly cover test.
Primary Areola shape: Sunken.
Primary Mamelon: Rounded.
Secondary tubercles: Scrobiculate.
Granules: Granulation covers test; more numerous nearing margin and below.
APICAL SYSTEM: Location: Posterior of center; about 40% from posterior margin.
Genital pores: Four gonopores.
PERIPROCT (ANUS): Shape & Size: Transversely oval; slight drop in middle.
Location: High on truncated posterior end; about 25% from margin.
PERISTOME (MOUTH): Shape: Rounded.
Location: Anterior; about 22% from anterior margin.
Visibility: Visible from posterior end.
SPECIMENS STUDIED & CONDITION: Hypotype BEG 34071.
ETYMOLOGY
Named in honor of Walter Scott Adkins (1890–1956), a preeminent Texas stratigrapher and paleontologist (Lambert, 1927).
REMARKS & COMPARISONS
Remarks: Miller (2009), in Preliminary Revision of Heteraster (Echinoidea) from the Lower Cretaceous of Texas, states that H. adkinsi is a synonym of Heteraster texanus (Roemer). The species is characterized by the distinct alternation of pore lengths in the unpaired ambulacrum, a hallmark of the genus Heteraster.
