Pliotoxaster donaldtrumpi Thompson, 2020
Plate: PlDo-10
Series: Lower Cretaceous Group: Fredericksburg Formation: Walnut
Locale: Mound County: Coryell Stage: Albian
Length: 44.1 mm Width: 38.9 mm Height: 29.3 mm
Collector: Dr. Stephen Crane
Holotype: NPL 94354
Repository: Non-vertebrate Paleo. Lab., Univ. of Texas
HOLOTYPE INFO:
Holotype: NPL 94354 .
Paratypes: NPL 94355 .
Locality: Mound, Coryell County, Texas.
Stratigraphy: Walnut Formation, Fredericksburg Group.
SYNONYMY
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: PLIOTOXASTER Fourtau, 1907
Species: Pliotoxaster donaldtrumpi Thompson, 2020
TYPE SPECIES: Pliotoxaster lyonsi Fourtau, 1907
DIAGNOSIS
A large Pliotoxaster from the Walnut Formation characterized by a very pronounced parafasciole. Distinguished from P. comanchei by an anteriorly positioned apical system, a deeply indented posterior truncation, and a "D" shaped, downward-facing peristome.
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Fredericksburg
Formations: Walnut Formation; Comanche Peak Formation.
Stratigraphic Units: Lower Cretaceous, Albian.
Counties: Coryell, Bell.
Abundance: Common (over 35 specimens studied).
Associated Fauna: Heteraster texanus, Tetragramma texanum, Phymosoma texanum.
DESCRIPTION
TOP: Length, width, height: 44.1 mm L × 38.9 mm W × 29.3 mm H (Holotype). Top shape: Oval with broad, slightly angular shoulders; narrower posteriorly. Anterior sulcus present. Top domed: Posterior end near flat; periproct visible from above.
SIDE: Ambitus: Rounded; positioned 35% of height from the adoral surface. Side shape: Inflated. Profile: Apex posterior of center. Posterior face obliquely truncated.
BOTTOM: Bottom shape: Adoral surface concave. Plastron: Large and triangular.
AMB: Amb shape: All 5 petals shallowly sunken. Unpaired ambulacrum (III) in a wide sulcus. Amb arrangement: Paired ambulacra petaloid, bowed from apical center, and open-ended. Anterior paired ambulacra are longer than the posterior pair.
PORE PAIRS: Shape: Unpaired amb: Pores circumflexed. Paired ambs: Pores elongated, slit-like, differentiated, with an interporal knob.
TUBERCLES: Distribution: Small, perforated, and crenulate. Scattered equally on adoral and aboral sides but more numerous at the ambitus and on the plastron.
GRANULES: See Tubercles.
FASCIOLE: Parafasciole: Very distinct parafasciole around the posterior. The band is made of granules (not clavulae).
APICAL SYSTEM: Location: Anterior of center. Type: Ethmophract. Genital pores: Four gonopores. Plating: Madreporite very large, mostly central. Genital plate 2 separates the posterior genital plates, but the posterior oculars touch.
PERIPROCT (ANUS): Shape: Longitudinal oval with pointed ends. Location: Set high on the obliquely truncated posterior end. Visibility: Visible from above.
PERISTOME (MOUTH): Shape: Small, pentagonal, "D" shaped. Size: Smaller than periproct. Orientation: Laying down (facing downward). Location: Farther anterior than in P. comanchei.
SPINES: Unknown.
SPECIMENS STUDIED & CONDITION: Holotype NPL 94354 and 35 other specimens. Paratypes NPL 94355.
ETYMOLOGY
Named to honor Donald John Trump, the 45th President of the United States.
REMARKS & COMPARISONS
Remarks: This species resolves the historical confusion regarding "Hemiaster comanchei" in the Fredericksburg Group. Smiser (1936) described Fredericksburg specimens (e.g., BEG 21270) as Palhemiaster comanchei, but the true P. comanchei (Clark, 1915) is restricted to the Glen Rose Formation (Trinity Group). P. donaldtrumpi is the valid name for the Walnut/Comanche Peak forms. It is also suggested that specimens previously misidentified as Lambertiaster ficheuri (a North African species with no valid North American record) may belong to this species, as Lambertiaster is morphologically similar to Pliotoxaster but differs in fasciole path.
Comparisons:
Remarks (01-2026): Some local fossil echinoid collectors report finding Lambertiaster ficherui which is known exclusively from Upper Cretaceous deposits in North Africa - specifically Tunisia and Algeria. Many specimens in the Steven & Frank Crane collection from Texas and southern Oklahoma were labeled as such and most were Hemiasters. Lamberiasters look very similar also to Pliotoxasters and I believe could have been also confused with P. donaldtrumpi. I have found no evidence of Lambertiaster echinoids in Texas.
Plate: PlDo-10
Series: Lower Cretaceous Group: Fredericksburg Formation: Walnut
Locale: Mound County: Coryell Stage: Albian
Length: 44.1 mm Width: 38.9 mm Height: 29.3 mm
Collector: Dr. Stephen Crane
Holotype: NPL 94354
Repository: Non-vertebrate Paleo. Lab., Univ. of Texas
HOLOTYPE INFO:
Holotype: NPL 94354 .
Paratypes: NPL 94355 .
Locality: Mound, Coryell County, Texas.
Stratigraphy: Walnut Formation, Fredericksburg Group.
SYNONYMY
- Hemiaster comanchei Clark, 1915 (partim; Fredericksburg specimens)
- Palhemiaster comanchei (Clark) Smiser, 1936 (Fredericksburg specimens, e.g., BEG 21270)
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: PLIOTOXASTER Fourtau, 1907
Species: Pliotoxaster donaldtrumpi Thompson, 2020
TYPE SPECIES: Pliotoxaster lyonsi Fourtau, 1907
DIAGNOSIS
A large Pliotoxaster from the Walnut Formation characterized by a very pronounced parafasciole. Distinguished from P. comanchei by an anteriorly positioned apical system, a deeply indented posterior truncation, and a "D" shaped, downward-facing peristome.
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Fredericksburg
Formations: Walnut Formation; Comanche Peak Formation.
Stratigraphic Units: Lower Cretaceous, Albian.
Counties: Coryell, Bell.
Abundance: Common (over 35 specimens studied).
Associated Fauna: Heteraster texanus, Tetragramma texanum, Phymosoma texanum.
DESCRIPTION
TOP: Length, width, height: 44.1 mm L × 38.9 mm W × 29.3 mm H (Holotype). Top shape: Oval with broad, slightly angular shoulders; narrower posteriorly. Anterior sulcus present. Top domed: Posterior end near flat; periproct visible from above.
SIDE: Ambitus: Rounded; positioned 35% of height from the adoral surface. Side shape: Inflated. Profile: Apex posterior of center. Posterior face obliquely truncated.
BOTTOM: Bottom shape: Adoral surface concave. Plastron: Large and triangular.
AMB: Amb shape: All 5 petals shallowly sunken. Unpaired ambulacrum (III) in a wide sulcus. Amb arrangement: Paired ambulacra petaloid, bowed from apical center, and open-ended. Anterior paired ambulacra are longer than the posterior pair.
PORE PAIRS: Shape: Unpaired amb: Pores circumflexed. Paired ambs: Pores elongated, slit-like, differentiated, with an interporal knob.
TUBERCLES: Distribution: Small, perforated, and crenulate. Scattered equally on adoral and aboral sides but more numerous at the ambitus and on the plastron.
GRANULES: See Tubercles.
FASCIOLE: Parafasciole: Very distinct parafasciole around the posterior. The band is made of granules (not clavulae).
APICAL SYSTEM: Location: Anterior of center. Type: Ethmophract. Genital pores: Four gonopores. Plating: Madreporite very large, mostly central. Genital plate 2 separates the posterior genital plates, but the posterior oculars touch.
PERIPROCT (ANUS): Shape: Longitudinal oval with pointed ends. Location: Set high on the obliquely truncated posterior end. Visibility: Visible from above.
PERISTOME (MOUTH): Shape: Small, pentagonal, "D" shaped. Size: Smaller than periproct. Orientation: Laying down (facing downward). Location: Farther anterior than in P. comanchei.
SPINES: Unknown.
SPECIMENS STUDIED & CONDITION: Holotype NPL 94354 and 35 other specimens. Paratypes NPL 94355.
ETYMOLOGY
Named to honor Donald John Trump, the 45th President of the United States.
REMARKS & COMPARISONS
Remarks: This species resolves the historical confusion regarding "Hemiaster comanchei" in the Fredericksburg Group. Smiser (1936) described Fredericksburg specimens (e.g., BEG 21270) as Palhemiaster comanchei, but the true P. comanchei (Clark, 1915) is restricted to the Glen Rose Formation (Trinity Group). P. donaldtrumpi is the valid name for the Walnut/Comanche Peak forms. It is also suggested that specimens previously misidentified as Lambertiaster ficheuri (a North African species with no valid North American record) may belong to this species, as Lambertiaster is morphologically similar to Pliotoxaster but differs in fasciole path.
Comparisons:
- Pliotoxaster comanchei: P. donaldtrumpi has an apical system anterior of center (vs. slightly posterior in comanchei). The apex is at the center in donaldtrumpi (vs. anterior in comanchei profile). The peristome in donaldtrumpi is D-shaped and further anterior, whereas comanchei is sub-hexagonal and less anterior. The periproct in comanchei is higher, more rounded, and wider. The ambitus is higher in comanchei.
Remarks (01-2026): Some local fossil echinoid collectors report finding Lambertiaster ficherui which is known exclusively from Upper Cretaceous deposits in North Africa - specifically Tunisia and Algeria. Many specimens in the Steven & Frank Crane collection from Texas and southern Oklahoma were labeled as such and most were Hemiasters. Lamberiasters look very similar also to Pliotoxasters and I believe could have been also confused with P. donaldtrumpi. I have found no evidence of Lambertiaster echinoids in Texas.
