Tetragramma donaldtrumpi Thompson, 2016
Plate: TeDo-10
Series: Lower Cretaceous Group: Trinity Formation: Glen Rose
Locale: Hancock County: Comal Stage: Albian
Length: 22.3 mm Height: 7.7 mm
Specimen in photo: NPL 73957 Holotype
Collector: William R. Thompson, Jr.
Repository: Non-vertebrate Paleo. Lab., Univ. of Texas
HOLOTYPE INFO:
Holotype: NPL 73957 .
Paratype: NPL 79482 .
Locality: Hancock, Comal County, Texas.
Stratigraphy: Salenia texana zone, Glen Rose Formation.
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: Diplopodiidae Smith & Wright, 1993
Genus: TETRAGRAMMA L. Agassiz, 1838
Species: Tetragramma donaldtrumpi Thompson, 2016
TYPE SPECIES: Cidarites variolare Brongniart, 1822
DIAGNOSIS
A Tetragramma characterized by four rows of tubercles in the interambulacra. The ambulacral plating is complex: quadrigeminate adorally, trigeminate near the oral plates, and quinquegeminate adapically.
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Trinity
Formations: Glen Rose Formation.
Stratigraphic Units: Lower Cretaceous, Albian.
Counties: Comal.
Abundance: Rare; only four specimens found.
Associated Fauna: Found in grey matrix associated with Leptosalenia texana, Heteraster obliquatus, Pliotoxaster comanchei, Coenholectypus planatus, and Coenholectypus ovatus.
DESCRIPTION
TOP: Length, width, height: 22.3 mm L × 7.7 mm H. Top shape: Round to slightly pentagonal. Top domed: Flattened upper surface.
SIDE: Ambitus: Positioned at midpoint. Side shape: Margin rounded.
BOTTOM: Bottom shape: Flattened lower surface.
AMB: Amb shape: Widest at ambitus; slightly narrower at peristome; narrower still at apical system. Amb arrangement: Two rows of 11–13 tubercles. Aborally, primary tuberculation of the ambulacra stop short of the apex.
Plating: Quinquegeminate (5 elements) adapically; Quadrigeminate (4 elements) adorally; Trigeminate (3 elements) near oral plates.
PORE PAIRS: Arrangement: Uniserial below margin; biserial above margin. Condition: Become crowded at peristome.
TUBERCLES: Primary Perforated: Yes. Primary Crenulate: Yes. Ambulacral Tubercles: Small; two rows of 11–13. Interambulacral Tubercles: Four rows total. Two inner rows (10 tubercles) run the entire length (widest at apical system, narrowest at peristome). Two outer rows (7–8 tubercles) run from 1/4 below the apical system to near the peristome. Tubercles are largest at the ambitus; outer rows decrease in size more quickly than inner rows.
GRANULES: Distribution: Granules run between tubercles in ambulacra. In interambulacra, miliary tubercles and granulation run the length of the interradial suture, becoming sparse above the ambitus and near the apical system.
FASCIOLE: Absent.
INTERAMB: Width: Just under twice the size of ambulacra at the margin.
APICAL SYSTEM: Size: Large; diameter about 48% of test. Shape: Sub-pentagonal.
PERIPROCT (ANUS): (Unknown).
PERISTOME (MOUTH): Size: Diameter 38% of test. Shape: Circular. Lip: Buccal notches small and pronounced.
SPINES: Unknown.
SPECIMENS STUDIED & CONDITION: Four specimens found in Hancock, Comal County. Holotype NPL 73957 and Paratype NPL 79482. Found by William R. Thompson, Jr.
ETYMOLOGY
Named in honor of Donald John Trump, the 45th President of the United States.
REMARKS & COMPARISONS
Remarks: This species is the only Glen Rose Tetragramma with four interambulacral rows combined with complex ambulacral plating (trigeminate near the oral plates, quadrigeminate adorally, and quinquegeminate adapically). The large apical system (≈48% of test) and relatively large peristome (38%) further separate it from other Trinity Tetragramma species. The material matches the Tetragramma plates figured as Tetragramma sp. by Smith & Rader (2009) and likely represents the same taxon. Earlier assignments of similar Glen Rose material to Diplopodia texanum and Tetragramma texanum reflect the long history of confusion between four‑row and six‑row species in the Texas Cretaceous.
Comparisons:
• Tetragramma malbosii (Colombia specimens): T. donaldtrumpi is very similar in having four interambulacral rows, but has a larger peristome, a larger and less distinctly pentagonal apical system, and more complex ambulacral plating. The Colombian material has a smaller, more clearly pentagonal apical system.
• Tetragramma texanum (sensu Roemer and later authors): T. texanum has six rows of interambulacral tubercles and a different pattern of ambulacral plating. T. donaldtrumpi is restricted to four rows and shows the tri–quadri–quinque plating sequence.
• Tetragramma hammerschmidti: T. hammerschmidti has six rows with 15–16 tubercles per row and a round apical system. T. donaldtrumpi has only four rows, fewer tubercles per row, and a larger, sub‑pentagonal apical system.
• Tetragramma cranei: T. cranei is smaller, more flattened, and has six rows with a 12–9–5 pattern. Its apical system is pentagonal and smaller relative to test size, and the ambulacral plating is simpler (quinquegeminate aborally, trigeminate adorally).
Plate: TeDo-10
Series: Lower Cretaceous Group: Trinity Formation: Glen Rose
Locale: Hancock County: Comal Stage: Albian
Length: 22.3 mm Height: 7.7 mm
Specimen in photo: NPL 73957 Holotype
Collector: William R. Thompson, Jr.
Repository: Non-vertebrate Paleo. Lab., Univ. of Texas
HOLOTYPE INFO:
Holotype: NPL 73957 .
Paratype: NPL 79482 .
Locality: Hancock, Comal County, Texas.
Stratigraphy: Salenia texana zone, Glen Rose Formation.
SYNONYMY
- Diplopodia texanum (Roemer); Whitney & Kellum, 1966
- Tetragramma texanum (Roemer); Akers & Akers, 1987
- Tetragramma sp. (Smith & Rader, 2009) (fide Thompson, 2016)
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: Diplopodiidae Smith & Wright, 1993
Genus: TETRAGRAMMA L. Agassiz, 1838
Species: Tetragramma donaldtrumpi Thompson, 2016
TYPE SPECIES: Cidarites variolare Brongniart, 1822
DIAGNOSIS
A Tetragramma characterized by four rows of tubercles in the interambulacra. The ambulacral plating is complex: quadrigeminate adorally, trigeminate near the oral plates, and quinquegeminate adapically.
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Trinity
Formations: Glen Rose Formation.
Stratigraphic Units: Lower Cretaceous, Albian.
Counties: Comal.
Abundance: Rare; only four specimens found.
Associated Fauna: Found in grey matrix associated with Leptosalenia texana, Heteraster obliquatus, Pliotoxaster comanchei, Coenholectypus planatus, and Coenholectypus ovatus.
DESCRIPTION
TOP: Length, width, height: 22.3 mm L × 7.7 mm H. Top shape: Round to slightly pentagonal. Top domed: Flattened upper surface.
SIDE: Ambitus: Positioned at midpoint. Side shape: Margin rounded.
BOTTOM: Bottom shape: Flattened lower surface.
AMB: Amb shape: Widest at ambitus; slightly narrower at peristome; narrower still at apical system. Amb arrangement: Two rows of 11–13 tubercles. Aborally, primary tuberculation of the ambulacra stop short of the apex.
Plating: Quinquegeminate (5 elements) adapically; Quadrigeminate (4 elements) adorally; Trigeminate (3 elements) near oral plates.
PORE PAIRS: Arrangement: Uniserial below margin; biserial above margin. Condition: Become crowded at peristome.
TUBERCLES: Primary Perforated: Yes. Primary Crenulate: Yes. Ambulacral Tubercles: Small; two rows of 11–13. Interambulacral Tubercles: Four rows total. Two inner rows (10 tubercles) run the entire length (widest at apical system, narrowest at peristome). Two outer rows (7–8 tubercles) run from 1/4 below the apical system to near the peristome. Tubercles are largest at the ambitus; outer rows decrease in size more quickly than inner rows.
GRANULES: Distribution: Granules run between tubercles in ambulacra. In interambulacra, miliary tubercles and granulation run the length of the interradial suture, becoming sparse above the ambitus and near the apical system.
FASCIOLE: Absent.
INTERAMB: Width: Just under twice the size of ambulacra at the margin.
APICAL SYSTEM: Size: Large; diameter about 48% of test. Shape: Sub-pentagonal.
PERIPROCT (ANUS): (Unknown).
PERISTOME (MOUTH): Size: Diameter 38% of test. Shape: Circular. Lip: Buccal notches small and pronounced.
SPINES: Unknown.
SPECIMENS STUDIED & CONDITION: Four specimens found in Hancock, Comal County. Holotype NPL 73957 and Paratype NPL 79482. Found by William R. Thompson, Jr.
ETYMOLOGY
Named in honor of Donald John Trump, the 45th President of the United States.
REMARKS & COMPARISONS
Remarks: This species is the only Glen Rose Tetragramma with four interambulacral rows combined with complex ambulacral plating (trigeminate near the oral plates, quadrigeminate adorally, and quinquegeminate adapically). The large apical system (≈48% of test) and relatively large peristome (38%) further separate it from other Trinity Tetragramma species. The material matches the Tetragramma plates figured as Tetragramma sp. by Smith & Rader (2009) and likely represents the same taxon. Earlier assignments of similar Glen Rose material to Diplopodia texanum and Tetragramma texanum reflect the long history of confusion between four‑row and six‑row species in the Texas Cretaceous.
Comparisons:
• Tetragramma malbosii (Colombia specimens): T. donaldtrumpi is very similar in having four interambulacral rows, but has a larger peristome, a larger and less distinctly pentagonal apical system, and more complex ambulacral plating. The Colombian material has a smaller, more clearly pentagonal apical system.
• Tetragramma texanum (sensu Roemer and later authors): T. texanum has six rows of interambulacral tubercles and a different pattern of ambulacral plating. T. donaldtrumpi is restricted to four rows and shows the tri–quadri–quinque plating sequence.
• Tetragramma hammerschmidti: T. hammerschmidti has six rows with 15–16 tubercles per row and a round apical system. T. donaldtrumpi has only four rows, fewer tubercles per row, and a larger, sub‑pentagonal apical system.
• Tetragramma cranei: T. cranei is smaller, more flattened, and has six rows with a 12–9–5 pattern. Its apical system is pentagonal and smaller relative to test size, and the ambulacral plating is simpler (quinquegeminate aborally, trigeminate adorally).
