Pedinopsis engerrandi Ikins, 1940
Plate: PeEn-10
Series: Lower Cretaceous Group: Fredericksburg Formation: Walnut
Locale: Harker Heights County: Bell County Stage: Albian
Length: 26.9 mm Height: 14.9 mm
Specimen in photo: NPL 83029 Hypotype
Collector: William R. Thompson, Jr.
Repository: Non-vertebrate Paleo. Lab., Univ. of Texas
Plate: PeEn-20
Series: Lower Cretaceous Group: Fredericksburg Formation: Walnut
Locale: Austin County: Travis Stage: Albian
Length: 15 mm Height: 7 mm
Specimen in photos: Collection of Ed Elliott
HOLOTYPE INFO:
Holotype: UT 40536 (BEG 40536) (Ikins, 1940).
Locality: 2 miles west of Leander, Williamson County, Texas.
Stratigraphy: Walnut Formation (Lower Fredericksburg).
Repository: Private Collection
SYNONYMY
SYSTEMATIC PALEONTOLOGY – TAXONOMY
Class: Echinoidea Leske, 1778
Subclass: Euechinoidea Bronn, 1860
Infraclass: Carinacea Kroh & Smith, 2010
Superorder: Calycina Gregory, 1900
Order: Phymosomatoida Mortensen, 1904
Family: Pedinopsidae Durham, 1955
Genus: PEDINOPSIS Cotteau, 1863
Species: Pedinopsis engerrandi Ikins, 1940
TYPE SPECIES: Pedinopsis meridanensis Cotteau, 1863
DIAGNOSIS
Test subglobular and inflated; poles symmetrical. Ambulacra straight with trigeminate plating; pore pairs arranged in broad arcs or staggered ranks (pseudo-biserial). Peristome large with distinct buccal notches. Tubercles perforate and crenulate.
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Fredericksburg
Formations: Walnut Formation; Comanche Peak Limestone.
Stratigraphic Units: Lower Cretaceous, Albian.
Counties: Bell, Williamson, Travis.
Abundance: Rare.
DESCRIPTION
TOP: Length, width, height: 26.9 mm L × 14.9 mm H. Top shape: Circular. Top domed: Symmetrical aborally.
SIDE: Ambitus: Positioned at midpoint. Side shape: Sub-globular; inflated.
BOTTOM: Bottom shape: Symmetrical adorally.
AMB: Amb shape: Lanceolate; widest at ambitus, narrowing slightly at peristome. Amb arrangement: Two rows of small primary tubercles run alongside the pore pairs. Width: Ambulacra are narrower than interambulacra.
PORE PAIRS: Arrangement: Grouped in sets of three (trigeminate), staggering up the ambulacra (forming arcs). Ikins (1940) describes the pores as biserial. Expand at peristome into phyllodes.
TUBERCLES: Primary Perforated: Yes. Primary Crenulate: Yes. Interambulacral Tubercles: Two rows of small primary tubercles run up the center of each plate. Distribution: Plates crowded with numerous small secondary tubercles.
GRANULES: Distribution: Dense granulation crowding the plates.
FASCIOLE: Absent.
APICAL SYSTEM: Size: Diameter 1/3 of test. Shape: Highly notched; disc has two small bulges at each ambulacrum and two larger bulges at each interambulacrum.
PERIPROCT (ANUS): (Unknown).
PERISTOME (MOUTH): Size: Diameter about 40% of test. Shape: Subpentagonal. Lip: Sunken. Features two notches inside each interambulacrum, cutting straight across to the next.
SPINES: Unknown.
SPECIMENS STUDIED & CONDITION: Hypotype NPL 83029. Collected by William R. Thompson, Jr.
ETYMOLOGY
Named in honor of George C. Engerrand (1877–1961), Professor of Anthropology and Geology at the University of Texas (Ikins, 1940).
REMARKS & COMPARISONS
Remarks: Cooke (1946) reviewed the types of Pedinopsis engerrandi and Pedinopsis yarboroughi (both described by Ikins in 1940) and concluded they represent the same species. P. yarboroughi has page priority, making P. engerrandi a junior synonym in Cooke's classification.
Comparisons:
Plate: PeEn-10
Series: Lower Cretaceous Group: Fredericksburg Formation: Walnut
Locale: Harker Heights County: Bell County Stage: Albian
Length: 26.9 mm Height: 14.9 mm
Specimen in photo: NPL 83029 Hypotype
Collector: William R. Thompson, Jr.
Repository: Non-vertebrate Paleo. Lab., Univ. of Texas
Plate: PeEn-20
Series: Lower Cretaceous Group: Fredericksburg Formation: Walnut
Locale: Austin County: Travis Stage: Albian
Length: 15 mm Height: 7 mm
Specimen in photos: Collection of Ed Elliott
HOLOTYPE INFO:
Holotype: UT 40536 (BEG 40536) (Ikins, 1940).
Locality: 2 miles west of Leander, Williamson County, Texas.
Stratigraphy: Walnut Formation (Lower Fredericksburg).
Repository: Private Collection
SYNONYMY
- Pedinopsis engerrandi Ikins, 1940
- Pedinopsis yarboroughi Ikins, 1940 (fide Cooke, 1946; Senior Synonym)
SYSTEMATIC PALEONTOLOGY – TAXONOMY
Class: Echinoidea Leske, 1778
Subclass: Euechinoidea Bronn, 1860
Infraclass: Carinacea Kroh & Smith, 2010
Superorder: Calycina Gregory, 1900
Order: Phymosomatoida Mortensen, 1904
Family: Pedinopsidae Durham, 1955
Genus: PEDINOPSIS Cotteau, 1863
Species: Pedinopsis engerrandi Ikins, 1940
TYPE SPECIES: Pedinopsis meridanensis Cotteau, 1863
DIAGNOSIS
Test subglobular and inflated; poles symmetrical. Ambulacra straight with trigeminate plating; pore pairs arranged in broad arcs or staggered ranks (pseudo-biserial). Peristome large with distinct buccal notches. Tubercles perforate and crenulate.
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Fredericksburg
Formations: Walnut Formation; Comanche Peak Limestone.
Stratigraphic Units: Lower Cretaceous, Albian.
Counties: Bell, Williamson, Travis.
Abundance: Rare.
DESCRIPTION
TOP: Length, width, height: 26.9 mm L × 14.9 mm H. Top shape: Circular. Top domed: Symmetrical aborally.
SIDE: Ambitus: Positioned at midpoint. Side shape: Sub-globular; inflated.
BOTTOM: Bottom shape: Symmetrical adorally.
AMB: Amb shape: Lanceolate; widest at ambitus, narrowing slightly at peristome. Amb arrangement: Two rows of small primary tubercles run alongside the pore pairs. Width: Ambulacra are narrower than interambulacra.
PORE PAIRS: Arrangement: Grouped in sets of three (trigeminate), staggering up the ambulacra (forming arcs). Ikins (1940) describes the pores as biserial. Expand at peristome into phyllodes.
TUBERCLES: Primary Perforated: Yes. Primary Crenulate: Yes. Interambulacral Tubercles: Two rows of small primary tubercles run up the center of each plate. Distribution: Plates crowded with numerous small secondary tubercles.
GRANULES: Distribution: Dense granulation crowding the plates.
FASCIOLE: Absent.
APICAL SYSTEM: Size: Diameter 1/3 of test. Shape: Highly notched; disc has two small bulges at each ambulacrum and two larger bulges at each interambulacrum.
PERIPROCT (ANUS): (Unknown).
PERISTOME (MOUTH): Size: Diameter about 40% of test. Shape: Subpentagonal. Lip: Sunken. Features two notches inside each interambulacrum, cutting straight across to the next.
SPINES: Unknown.
SPECIMENS STUDIED & CONDITION: Hypotype NPL 83029. Collected by William R. Thompson, Jr.
ETYMOLOGY
Named in honor of George C. Engerrand (1877–1961), Professor of Anthropology and Geology at the University of Texas (Ikins, 1940).
REMARKS & COMPARISONS
Remarks: Cooke (1946) reviewed the types of Pedinopsis engerrandi and Pedinopsis yarboroughi (both described by Ikins in 1940) and concluded they represent the same species. P. yarboroughi has page priority, making P. engerrandi a junior synonym in Cooke's classification.
Comparisons:
- Pedinopsis texana: P. engerrandi is distinguished by tubercle size and pore arrangement details.
