Archaeocidaris sp. McCoy, 1884
Plate: ArSp-10
Series: Pennsylvanian Group: Cisco Formation: Thrifty
Locale: Cisco County: Eastland Stage: Virgilian Stage / Gzhelian
Length: 10.5 mm (largest)
Specimen in photo: Collection of Terry Stephenson Plates
Plate: ArSp-20
Series: Pennsylvanian Group: Cisco Formation: Thrifty
Locale: Cisco County: Eastland Stage: Virgilian Stage / Gzhelian
Length: 41.5 mm (largest) Width: 25.0 mm Height: 4.6 mm
Specimen in photo: Collection of Terry Stephenson Plates repaired with glue.
Plate: ArSp-30
Series: Pennsylvanian Group: Cisco Formation: Thrifty
Locale: Cisco County: Eastland Stage: Virgilian Stage / Gzhelian
Length: 47.8 mm (longest) Width: 3.5 mm
Specimen in photo: Collection of Terry Stephenson Spines
Plate: ArSp-40
Series: Pennsylvanian Group: Canyon
Locale: Bridgeport County: Wise Stage: Atokan/Desmoinesian
Length: 109.1 mm Width: 7.8 mm
Specimen in photo: Collection of Ed Elliott Spine
Plate: ArSp-50
Series: Pennsylvanian Group: Kickapoo Creek Formation: Dickerson Shale
Locale: Kickapoo Falls County: Hood Stage: Dosmoinesian
Longest Length: 51.4 mm Width: 6.8 mm
Specimen in photo: Collection of Frank Crane Spine
Plate: ArSp-60
Series: Pennsylvanian Group: Canyon
Locale: Bridgeport County: Wise Stage: Atokan/Desmoinesian
Length: 26.1 mm Width: 19.4 mm Height: 9.5 mm
Specimen in photo: Collection of Ed Elliott Pyramid from Aristotle's Lantern
Systematic Paleontology
CLASS: ECHINOIDEA Leske, 1778
SUBCLASS: PERISCHOECHINOIDEA M'Coy, 1849
ORDER: ARCHAEOCIDAROIDA Vadet, 1988
FAMILY: ARCHAEOCIDARIDAE McCoy, 1844
GENUS: ARCHAEOCIDARIS McCoy, 1844
SPECIES: Archaeocidaris sp.
TYPE SPECIES: Cidaris urii Fleming, 1828
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Canyon (Eastland/Wise Co.), Kickapoo Creek (Hood Co.)
Formations: Thrifty Formation, Dickerson Shale
Stratigraphic Units: Pennsylvanian; Moscovian, Kasimovian, Desmoinesian
Counties: Eastland, Wise, Hood
DESCRIPTION
TOP: Top shape: Test is depressed spheroidal (Jackson, 1912)
AMB: Amb shape: Narrow, sinuous in outline (Jackson, 1912)
Amb primary zones: Plates low, uniform, imbricating moderately adorally; beveled strongly under adradials (Jackson, 1912)
INTERAMB: Interamb plates per row: Four columns of plates in each interambulacral area (Jackson, 1912)
Interamb plate shape: Adradial plates pentagonal (rounded on adradial suture); intermediate columns hexagonal (Jackson, 1912)
Interamb primary tubercles: Each plate bears a prominent perforate median tubercle (Jackson, 1912)
Interamb granules: Secondary tubercles beyond the scrobicular border (Jackson, 1912)
PORE PAIRS: Arrangement: Uniserial (Jackson, 1912)
SUTURES: Primary Perforated: Yes (Jackson, 1912)
Primary Boss: Basal terrace present (Jackson, 1912)
Primary Areola shape: Wide scrobicular area (Jackson, 1912)
TUBERCLES: Primary tubercles: Prominent, perforate (Jackson, 1912)
PERIPROCT (ANUS): Shape & Size: Many small angular plates (Jackson, 1912)
PERISTOME (MOUTH): Shape: Covered with radially situated ambulacral and interradially situated non-ambulacral plates; all small and imbricating adorally (Jackson, 1912)
Plate ArSp-60, is a single pyramid from the Aristotle’s Lantern, showing the classic Paleozoic cidaroid architecture described by Jackson (1912). Five‑sided, tapering upward to a sharp apex; basal margins deeply indented where the epiphyses and tooth sockets would articulate. Smooth to faintly striated; sutures between pyramid plates clearly visible. Fine calcitic detail with minimal distortion; matrix adherent only at the basal end. Pale gray‑tan with slight yellow patina from diagenetic iron oxides.
The enclosed tooth is elongate, triangular, tapering to a sharp cutting edge; basal end deeply concave for articulation with the pyramid. Finely striated longitudinally, with subtle transverse growth lines; the striae converge toward the apex, producing a faintly corrugated texture typical of Paleozoic cidaroid teeth. Cross section is compressed and blade‑like, with a rounded aboral surface and a flattened oral face. Apex is slightly recurved, indicating wear from grazing on firm carbonate substrates. It has crisp edges and minimal distortion.
SPINES: Shape: Relatively large; shaft tapering or enlarged (Jackson, 1912)
Length: Up to 109.1 mm
Base: Concave base with marked milled ring (Jackson, 1912)
Ornamentation: Smooth or ornamented with striations, spinules, or flange-like vertical ridges (Jackson, 1912)
SPECIMENS STUDIED & CONDITION
Specimen condition: Fragmentary material including isolated plates, spines (up to 109.1 mm), and a lantern pyramid .
REMARKS & COMPARISONS
Remarks: The specimens described here represent indeterminate species of Archaeocidaris from various Pennsylvanian localities in Texas. The genus is characterized by flexible tests with 4 columns of interambulacral plates and large primary spines (Jackson, 1912).
Comparisons: The spines and plates likely belong to species such as Archaeocidaris brownwoodensis or A. apheles, which co-occur in the Texas Pennsylvanian, but isolated material is difficult to assign to a specific species without associated test features.
Plate: ArSp-10
Series: Pennsylvanian Group: Cisco Formation: Thrifty
Locale: Cisco County: Eastland Stage: Virgilian Stage / Gzhelian
Length: 10.5 mm (largest)
Specimen in photo: Collection of Terry Stephenson Plates
Plate: ArSp-20
Series: Pennsylvanian Group: Cisco Formation: Thrifty
Locale: Cisco County: Eastland Stage: Virgilian Stage / Gzhelian
Length: 41.5 mm (largest) Width: 25.0 mm Height: 4.6 mm
Specimen in photo: Collection of Terry Stephenson Plates repaired with glue.
Plate: ArSp-30
Series: Pennsylvanian Group: Cisco Formation: Thrifty
Locale: Cisco County: Eastland Stage: Virgilian Stage / Gzhelian
Length: 47.8 mm (longest) Width: 3.5 mm
Specimen in photo: Collection of Terry Stephenson Spines
Plate: ArSp-40
Series: Pennsylvanian Group: Canyon
Locale: Bridgeport County: Wise Stage: Atokan/Desmoinesian
Length: 109.1 mm Width: 7.8 mm
Specimen in photo: Collection of Ed Elliott Spine
Plate: ArSp-50
Series: Pennsylvanian Group: Kickapoo Creek Formation: Dickerson Shale
Locale: Kickapoo Falls County: Hood Stage: Dosmoinesian
Longest Length: 51.4 mm Width: 6.8 mm
Specimen in photo: Collection of Frank Crane Spine
Plate: ArSp-60
Series: Pennsylvanian Group: Canyon
Locale: Bridgeport County: Wise Stage: Atokan/Desmoinesian
Length: 26.1 mm Width: 19.4 mm Height: 9.5 mm
Specimen in photo: Collection of Ed Elliott Pyramid from Aristotle's Lantern
Systematic Paleontology
CLASS: ECHINOIDEA Leske, 1778
SUBCLASS: PERISCHOECHINOIDEA M'Coy, 1849
ORDER: ARCHAEOCIDAROIDA Vadet, 1988
FAMILY: ARCHAEOCIDARIDAE McCoy, 1844
GENUS: ARCHAEOCIDARIS McCoy, 1844
SPECIES: Archaeocidaris sp.
TYPE SPECIES: Cidaris urii Fleming, 1828
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Canyon (Eastland/Wise Co.), Kickapoo Creek (Hood Co.)
Formations: Thrifty Formation, Dickerson Shale
Stratigraphic Units: Pennsylvanian; Moscovian, Kasimovian, Desmoinesian
Counties: Eastland, Wise, Hood
DESCRIPTION
TOP: Top shape: Test is depressed spheroidal (Jackson, 1912)
AMB: Amb shape: Narrow, sinuous in outline (Jackson, 1912)
Amb primary zones: Plates low, uniform, imbricating moderately adorally; beveled strongly under adradials (Jackson, 1912)
INTERAMB: Interamb plates per row: Four columns of plates in each interambulacral area (Jackson, 1912)
Interamb plate shape: Adradial plates pentagonal (rounded on adradial suture); intermediate columns hexagonal (Jackson, 1912)
Interamb primary tubercles: Each plate bears a prominent perforate median tubercle (Jackson, 1912)
Interamb granules: Secondary tubercles beyond the scrobicular border (Jackson, 1912)
PORE PAIRS: Arrangement: Uniserial (Jackson, 1912)
SUTURES: Primary Perforated: Yes (Jackson, 1912)
Primary Boss: Basal terrace present (Jackson, 1912)
Primary Areola shape: Wide scrobicular area (Jackson, 1912)
TUBERCLES: Primary tubercles: Prominent, perforate (Jackson, 1912)
PERIPROCT (ANUS): Shape & Size: Many small angular plates (Jackson, 1912)
PERISTOME (MOUTH): Shape: Covered with radially situated ambulacral and interradially situated non-ambulacral plates; all small and imbricating adorally (Jackson, 1912)
Plate ArSp-60, is a single pyramid from the Aristotle’s Lantern, showing the classic Paleozoic cidaroid architecture described by Jackson (1912). Five‑sided, tapering upward to a sharp apex; basal margins deeply indented where the epiphyses and tooth sockets would articulate. Smooth to faintly striated; sutures between pyramid plates clearly visible. Fine calcitic detail with minimal distortion; matrix adherent only at the basal end. Pale gray‑tan with slight yellow patina from diagenetic iron oxides.
The enclosed tooth is elongate, triangular, tapering to a sharp cutting edge; basal end deeply concave for articulation with the pyramid. Finely striated longitudinally, with subtle transverse growth lines; the striae converge toward the apex, producing a faintly corrugated texture typical of Paleozoic cidaroid teeth. Cross section is compressed and blade‑like, with a rounded aboral surface and a flattened oral face. Apex is slightly recurved, indicating wear from grazing on firm carbonate substrates. It has crisp edges and minimal distortion.
SPINES: Shape: Relatively large; shaft tapering or enlarged (Jackson, 1912)
Length: Up to 109.1 mm
Base: Concave base with marked milled ring (Jackson, 1912)
Ornamentation: Smooth or ornamented with striations, spinules, or flange-like vertical ridges (Jackson, 1912)
SPECIMENS STUDIED & CONDITION
Specimen condition: Fragmentary material including isolated plates, spines (up to 109.1 mm), and a lantern pyramid .
REMARKS & COMPARISONS
Remarks: The specimens described here represent indeterminate species of Archaeocidaris from various Pennsylvanian localities in Texas. The genus is characterized by flexible tests with 4 columns of interambulacral plates and large primary spines (Jackson, 1912).
Comparisons: The spines and plates likely belong to species such as Archaeocidaris brownwoodensis or A. apheles, which co-occur in the Texas Pennsylvanian, but isolated material is difficult to assign to a specific species without associated test features.
