Echinothuria mccallae Thompson, 2016
Plate: EcMc-10
Series: Lower Cretaceous Group: Trinity Formation: Glen rose
Locale: Startzville County: Comal Stage: Albian
Length: 50.5 mm Width: 47.28 mm
Specimen in photo: NPL 64373A Holotype
University of Texas Non-vertebrate Paleo. Lab.
Collector: Linda McCall Partially articulated interamb plates.
Plate: EcMc-20
Locale: Startzville County: Comal
Length: 19.3 mm Width: 17.0 mm
Specimen in photo: NPL 64373B Paratype
University of Texas Non-vertebrate Paleo. Lab.
Collector: Linda McCall Partially articulated interamb plates.
Plate: EcMc-30
Locale: Startzville County: Comal
Length: 23 mm Width: 5 mm Height: 1 mm
Specimens in photos: NPL 73955 Hypotype
University of Texas Non-vertebrate Paleo. Lab.
Collector: William R. Thompson, Jr. In-articulated interamb plates.
Plate: EcMc-40
Locale: Startzville County: Comal
Length: 23 mm Width: 5 mm Height: 1 mm
Specimens in photos: NPL 73955 Hypotype
University of Texas Non-vertebrate Paleo. Lab.
Collector: William R. Thompson, Jr. In-articulated amb plates.
Plate: EcMc-50
Locale: Startzville County: Comal
Length: 11.3 mm Width: 5.4 mm Height: 2.6 mm
Specimens in photos: NPL 73955 Hypotype
University of Texas Non-vertebrate Paleo. Lab.
Collector: William R. Thompson, Jr. Rotula
Plate: EcMc-60
Locale: Startzville County: Comal
Length: 19.2 mm (longest) Width: 3.8 mm
Specimens in photos: NPL 73955 Hypotype
University of Texas Non-vertebrate Paleo. Lab.
Collector: William R. Thompson, Jr. Spines
Plate: EcMc-70
Locale: Spring Branch County: Comal
Length: 10.1 mm Width: 3.9 mm Height: 2.2 mm
Specimens in photos: NPL 73955 Hypotype
University of Texas Non-vertebrate Paleo. Lab.
Collector: William R. Thompson, Jr. Hemi-pyramids
Plate: EcMc-80
Locale: Spring Branch County: Comal
Length: 19.1 mm Width: 8.1 mm Height: 6.4 mm
Specimens in photos: NPL 73955 Hypotype
University of Texas Non-vertebrate Paleo. Lab.
Collector: William R. Thompson, Jr. Pyramid and tooth, articulated
Plate: EcMc-90
Locale: Spring Branch County: Comal
Length: 13.0 mm Width: 2.7 mm Height: 1.3 mm
Specimens in photos: NPL 73955 Hypotype
University of Texas Non-vertebrate Paleo. Lab.
Collector: William R. Thompson, Jr. Tooth
Plate: EcMc-95
Locale: Spring Branch County: Comal
Length: 0.4 mm Width: 0.3 mm Height: 0.2 mm
Specimens in photos: NPL 73955 Hypotype
University of Texas Non-vertebrate Paleo. Lab.
Collector: William R. Thompson, Jr. Compass
SYSTEMATIC PALEONTOLOGY – TAXONOMY
Class: Echinoidea Leske, 1778
Subclass: Euechinoidea Bronn, 1860
Infraclass: Aulodonta Jackson, 1912
Superorder: Echinothuriacea Jensen, 1982
Order: Echinothurioida Claus, 1880
Family: Echinothuriidae Wyville Thomson, 1872
Subfamily: Echinothuriinae Wyville Thomson, 1872
Genus: ECHINOTHURIA Woodward, 1863
Species: Echinothuria mccallae Thompson, 2016
TYPE SPECIES: Echinothuria floris Woodward, 1863
DIAGNOSIS
An Echinothuria from the Lower Cretaceous of Texas. Pore pairs arranged in 3 columns, two sets are on small accessory plates separate from the ambulacral plates. On the two sides of each hemi-pyramid pair is a "nostril shaped" indentation, unlike the full length indentation in Echinothuria floris .
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Stratigraphic Units: Lower Cretaceous
Counties: Comal
DESCRIPTION
TOP: Top shape: Appears large, probably globular
Structure: Plates imbricating; inarticulated (flexible test)
AMB: Amb shape: Narrow in middle, widest on either side like a bowtie
Amb size: Smaller than interambs; probably about half size of interambs
Amb primary tubercles: Some plates have one or two primary tubercles, some have granules
Amb arrangement: Two accessory plates sit in the narrow part of the amb plate
Accessory plates: Teardrop shaped, oblique, near half-spherical, very small; two per amb plate
INTERAMB: Interamb plating: Large, machete-shaped plates; appear imbricated
Interamb primary tubercles: Some plates have four primary tubercles concentrated on upper halves
Interamb granules: Numerous minute granules; minute perforated granules numerous on some plates
PORE PAIRS: Arrangement: Arranged in 3 columns. One set on each of the two separate tiny accessory plates. Third set of pore pairs located between the accessory plates and the adradial suture .
TUBERCLES: Primary Perforated: Yes
Primary Areola shape: Large sunken areola
Secondary tubercles: Scrobicular tubercles surround largest tubercles
APICAL SYSTEM: Unknown
PERIPROCT (ANUS): Unknown
PERISTOME (MOUTH): Unknown
Lantern:
Collar: Base of collar serrated, then tapers. Just below collar is an indented ring. Collar and hoof-like end about equal in circumference .
Ornamentation: About 18 rows of bumps ("pumps") on shaft, giving corn cob appearance. Ornamentation stops near end, turning into smooth hoof-like end .
Perforation: Tip at base perforated; hoof-like end also perforated .
SPECIMENS STUDIED & CONDITION
Specimen condition: Partially articulated specimens are extremely rare. Description based on parts from many specimens, including NPL 64373 and NPL 73955 .
ETYMOLOGY: Named after Linda McCall, Research Fellow - University Texas at Austin, and who found several nice partially articulated specimens .
REMARKS & COMPARISONS
Remarks: Similar to Echinothuria floris from the late Cretaceous.
Comparisons:
Plate: EcMc-10
Series: Lower Cretaceous Group: Trinity Formation: Glen rose
Locale: Startzville County: Comal Stage: Albian
Length: 50.5 mm Width: 47.28 mm
Specimen in photo: NPL 64373A Holotype
University of Texas Non-vertebrate Paleo. Lab.
Collector: Linda McCall Partially articulated interamb plates.
Plate: EcMc-20
Locale: Startzville County: Comal
Length: 19.3 mm Width: 17.0 mm
Specimen in photo: NPL 64373B Paratype
University of Texas Non-vertebrate Paleo. Lab.
Collector: Linda McCall Partially articulated interamb plates.
Plate: EcMc-30
Locale: Startzville County: Comal
Length: 23 mm Width: 5 mm Height: 1 mm
Specimens in photos: NPL 73955 Hypotype
University of Texas Non-vertebrate Paleo. Lab.
Collector: William R. Thompson, Jr. In-articulated interamb plates.
Plate: EcMc-40
Locale: Startzville County: Comal
Length: 23 mm Width: 5 mm Height: 1 mm
Specimens in photos: NPL 73955 Hypotype
University of Texas Non-vertebrate Paleo. Lab.
Collector: William R. Thompson, Jr. In-articulated amb plates.
Plate: EcMc-50
Locale: Startzville County: Comal
Length: 11.3 mm Width: 5.4 mm Height: 2.6 mm
Specimens in photos: NPL 73955 Hypotype
University of Texas Non-vertebrate Paleo. Lab.
Collector: William R. Thompson, Jr. Rotula
Plate: EcMc-60
Locale: Startzville County: Comal
Length: 19.2 mm (longest) Width: 3.8 mm
Specimens in photos: NPL 73955 Hypotype
University of Texas Non-vertebrate Paleo. Lab.
Collector: William R. Thompson, Jr. Spines
Plate: EcMc-70
Locale: Spring Branch County: Comal
Length: 10.1 mm Width: 3.9 mm Height: 2.2 mm
Specimens in photos: NPL 73955 Hypotype
University of Texas Non-vertebrate Paleo. Lab.
Collector: William R. Thompson, Jr. Hemi-pyramids
Plate: EcMc-80
Locale: Spring Branch County: Comal
Length: 19.1 mm Width: 8.1 mm Height: 6.4 mm
Specimens in photos: NPL 73955 Hypotype
University of Texas Non-vertebrate Paleo. Lab.
Collector: William R. Thompson, Jr. Pyramid and tooth, articulated
Plate: EcMc-90
Locale: Spring Branch County: Comal
Length: 13.0 mm Width: 2.7 mm Height: 1.3 mm
Specimens in photos: NPL 73955 Hypotype
University of Texas Non-vertebrate Paleo. Lab.
Collector: William R. Thompson, Jr. Tooth
Plate: EcMc-95
Locale: Spring Branch County: Comal
Length: 0.4 mm Width: 0.3 mm Height: 0.2 mm
Specimens in photos: NPL 73955 Hypotype
University of Texas Non-vertebrate Paleo. Lab.
Collector: William R. Thompson, Jr. Compass
SYSTEMATIC PALEONTOLOGY – TAXONOMY
Class: Echinoidea Leske, 1778
Subclass: Euechinoidea Bronn, 1860
Infraclass: Aulodonta Jackson, 1912
Superorder: Echinothuriacea Jensen, 1982
Order: Echinothurioida Claus, 1880
Family: Echinothuriidae Wyville Thomson, 1872
Subfamily: Echinothuriinae Wyville Thomson, 1872
Genus: ECHINOTHURIA Woodward, 1863
Species: Echinothuria mccallae Thompson, 2016
TYPE SPECIES: Echinothuria floris Woodward, 1863
DIAGNOSIS
An Echinothuria from the Lower Cretaceous of Texas. Pore pairs arranged in 3 columns, two sets are on small accessory plates separate from the ambulacral plates. On the two sides of each hemi-pyramid pair is a "nostril shaped" indentation, unlike the full length indentation in Echinothuria floris .
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Stratigraphic Units: Lower Cretaceous
Counties: Comal
DESCRIPTION
TOP: Top shape: Appears large, probably globular
Structure: Plates imbricating; inarticulated (flexible test)
AMB: Amb shape: Narrow in middle, widest on either side like a bowtie
Amb size: Smaller than interambs; probably about half size of interambs
Amb primary tubercles: Some plates have one or two primary tubercles, some have granules
Amb arrangement: Two accessory plates sit in the narrow part of the amb plate
Accessory plates: Teardrop shaped, oblique, near half-spherical, very small; two per amb plate
INTERAMB: Interamb plating: Large, machete-shaped plates; appear imbricated
Interamb primary tubercles: Some plates have four primary tubercles concentrated on upper halves
Interamb granules: Numerous minute granules; minute perforated granules numerous on some plates
PORE PAIRS: Arrangement: Arranged in 3 columns. One set on each of the two separate tiny accessory plates. Third set of pore pairs located between the accessory plates and the adradial suture .
TUBERCLES: Primary Perforated: Yes
Primary Areola shape: Large sunken areola
Secondary tubercles: Scrobicular tubercles surround largest tubercles
APICAL SYSTEM: Unknown
PERIPROCT (ANUS): Unknown
PERISTOME (MOUTH): Unknown
Lantern:
- Hemi-pyramids: Claw-like with pointed end; curved with one long serrated side and one shorter smooth side. Pair looks like a bird beak. Indentation ("nostril shaped") on either side for about 5/6th of length .
- Foramen magnum: Very small, rounded .
- Tooth: Long, bent like angle iron; flat on one end, tapering to point at distal end (taper runs <1/3rd length). Slight curve; tooth band runs entire length .
- Rotula: Pointed on both ends; two outward protrusions on long sides. Underside patterned. Length >2x width .
- Compass: Y-shaped; slightly longer than wide. Socket-like sides; end notched; thickest at center .
Collar: Base of collar serrated, then tapers. Just below collar is an indented ring. Collar and hoof-like end about equal in circumference .
Ornamentation: About 18 rows of bumps ("pumps") on shaft, giving corn cob appearance. Ornamentation stops near end, turning into smooth hoof-like end .
Perforation: Tip at base perforated; hoof-like end also perforated .
SPECIMENS STUDIED & CONDITION
Specimen condition: Partially articulated specimens are extremely rare. Description based on parts from many specimens, including NPL 64373 and NPL 73955 .
ETYMOLOGY: Named after Linda McCall, Research Fellow - University Texas at Austin, and who found several nice partially articulated specimens .
REMARKS & COMPARISONS
Remarks: Similar to Echinothuria floris from the late Cretaceous.
Comparisons:
- Echinothuria floris: Has some pore pairs on large amb plates (unlike E. mccallae where they do not exist on large plates). The hemi-pyramids in E. floris have a large V-shaped foramen magnum (vs. small rounded in E. mccallae) and the sides are indented for the full length (vs. "nostril" shape in E. mccallae) .
- General: All other echinoids from the Family Echinothuriidae are younger (Upper Cretaceous to Recent) .
