Diplopodia doliae Thompson, 2016
Plate: DiDo-10
Series: Lower Cretaceous Group: Fredericksburg Formation: Comanche Peak
Locale: Goldthwaite County: Mills Stage: Albian
Length: 31.4 mm Height: 12.7 mm
Specimen in photo: NPL 73954 Holotype
Collector: Terry Stephenson
University of Texas Non-vertebrate Paleo. Lab. Crushed.
Plate: DiDo-20
Series: Lower Cretaceous Group: Fredericksburg Formation: Comanche Peak
Locale: Copperas Cove County: Coryell Stage: Albian
Length: 25.2 mm Height: 12.2 mm
Collector: Kevin Durney
HOLOTYPE INFO:
Holotype: NPL 73954 — Non-vertebrate Paleontology Laboratory, University of Texas
Locality: Goldthwaite, Mills County, Texas
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: DIPLOPODIA McCoy, 1848
Species: Diplopodia doliae Thompson, 2016
TYPE SPECIES: Diplopodia pentagona McCoy, 1848
DIAGNOSIS
A Diplopodia from the Lower Cretaceous of Texas with two rows of primary tubercles in the interambulacrum and smaller tubercles and granules along the adradial and interradial sutures .
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Fredericksburg
Formations: Comanche Peak Formation
Stratigraphic Units: Lower Cretaceous, Albian
Counties: Mills, Coryell
DESCRIPTION
TOP: Top shape: Pentagonal from above
Flatness: Flattened upper surface
SIDE: Ambitus: At midpoint (Holotype); about 40% from base (DiDo-20)
Side shape: Barrel shaped
BOTTOM: Bottom flat: Flattened lower surface
AMB: Amb width: Widest at ambitus; tapers at peristome and apical system
Amb primary tubercles: Two rows of 12 tubercles; one primary tubercle centers each amb plate
Amb arrangement: Pore pairs uniserial below margin, biserial above. Plating polygeminate (5 elements) above ambitus; trigeminate (3 elements) orally
INTERAMB: Interamb width: Over 1.8 times width of ambulacra at margin
Interamb plating: Plates 1.7 times wider than amb plates, equal in height
Interamb primary tubercles: Two rows of 9–10 tubercles run the entire interambulacrum; one primary tubercle centers each plate
PORE PAIRS: Arrangement: Uniserial below margin, biserial above
TUBERCLES: Primary Perforated: Yes
Primary Crenulate: Yes
Primary Mamelon: Small
Size: Largest at ambitus; decrease in size in either direction, decreasing more quickly aborally
Secondary tubercles: Miliary tubercles and granulation run length of adradial suture and between amb tubercles; half the size or less of primary tubercles
Granules: Granulation at interradial suture; sparse near apical system
APICAL SYSTEM: Size: Diameter of apical scar 50–55% of diameter of test
Shape: Subpentagonal; slightly cuts into each interambulacrum and ambulacrum
PERIPROCT (ANUS): Shape & Size: Pentagonal; width 41% of apical system width; concave dip (DiDo-20)
Location: Pointing at interradials
PERISTOME (MOUTH): Size: Diameter 45% (Holotype) to 49% (DiDo-20) of diameter of test
Shape: Circular
Lip: Buccal notches very small, but pronounced
SPECIMENS STUDIED & CONDITION
Specimen condition: Two specimens studied. Holotype NPL 73954 (Crushed). Specimen DiDo-20 (Kevin Durney Collection) is uncrushed .
ETYMOLOGY: Named "doliae", Latin word for "barrel" .
REMARKS & COMPARISONS
Remarks: This was the only known Diplopodia in Texas at the time of description. The lack of enlarged secondary tubercles establishes this as Diplopodia rather than Tetragramma. The uncrushed specimen (DiDo-20) confirms the presence of Diplopodia in the Cretaceous, whereas most species are Jurassic.
Comparisons:
Plate: DiDo-10
Series: Lower Cretaceous Group: Fredericksburg Formation: Comanche Peak
Locale: Goldthwaite County: Mills Stage: Albian
Length: 31.4 mm Height: 12.7 mm
Specimen in photo: NPL 73954 Holotype
Collector: Terry Stephenson
University of Texas Non-vertebrate Paleo. Lab. Crushed.
Plate: DiDo-20
Series: Lower Cretaceous Group: Fredericksburg Formation: Comanche Peak
Locale: Copperas Cove County: Coryell Stage: Albian
Length: 25.2 mm Height: 12.2 mm
Collector: Kevin Durney
HOLOTYPE INFO:
Holotype: NPL 73954 — Non-vertebrate Paleontology Laboratory, University of Texas
Locality: Goldthwaite, Mills County, Texas
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: DIPLOPODIA McCoy, 1848
Species: Diplopodia doliae Thompson, 2016
TYPE SPECIES: Diplopodia pentagona McCoy, 1848
DIAGNOSIS
A Diplopodia from the Lower Cretaceous of Texas with two rows of primary tubercles in the interambulacrum and smaller tubercles and granules along the adradial and interradial sutures .
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Fredericksburg
Formations: Comanche Peak Formation
Stratigraphic Units: Lower Cretaceous, Albian
Counties: Mills, Coryell
DESCRIPTION
TOP: Top shape: Pentagonal from above
Flatness: Flattened upper surface
SIDE: Ambitus: At midpoint (Holotype); about 40% from base (DiDo-20)
Side shape: Barrel shaped
BOTTOM: Bottom flat: Flattened lower surface
AMB: Amb width: Widest at ambitus; tapers at peristome and apical system
Amb primary tubercles: Two rows of 12 tubercles; one primary tubercle centers each amb plate
Amb arrangement: Pore pairs uniserial below margin, biserial above. Plating polygeminate (5 elements) above ambitus; trigeminate (3 elements) orally
INTERAMB: Interamb width: Over 1.8 times width of ambulacra at margin
Interamb plating: Plates 1.7 times wider than amb plates, equal in height
Interamb primary tubercles: Two rows of 9–10 tubercles run the entire interambulacrum; one primary tubercle centers each plate
PORE PAIRS: Arrangement: Uniserial below margin, biserial above
TUBERCLES: Primary Perforated: Yes
Primary Crenulate: Yes
Primary Mamelon: Small
Size: Largest at ambitus; decrease in size in either direction, decreasing more quickly aborally
Secondary tubercles: Miliary tubercles and granulation run length of adradial suture and between amb tubercles; half the size or less of primary tubercles
Granules: Granulation at interradial suture; sparse near apical system
APICAL SYSTEM: Size: Diameter of apical scar 50–55% of diameter of test
Shape: Subpentagonal; slightly cuts into each interambulacrum and ambulacrum
PERIPROCT (ANUS): Shape & Size: Pentagonal; width 41% of apical system width; concave dip (DiDo-20)
Location: Pointing at interradials
PERISTOME (MOUTH): Size: Diameter 45% (Holotype) to 49% (DiDo-20) of diameter of test
Shape: Circular
Lip: Buccal notches very small, but pronounced
SPECIMENS STUDIED & CONDITION
Specimen condition: Two specimens studied. Holotype NPL 73954 (Crushed). Specimen DiDo-20 (Kevin Durney Collection) is uncrushed .
ETYMOLOGY: Named "doliae", Latin word for "barrel" .
REMARKS & COMPARISONS
Remarks: This was the only known Diplopodia in Texas at the time of description. The lack of enlarged secondary tubercles establishes this as Diplopodia rather than Tetragramma. The uncrushed specimen (DiDo-20) confirms the presence of Diplopodia in the Cretaceous, whereas most species are Jurassic.
Comparisons:
- Diplopodia pentagona: D. doliae differs by having shallower buccal notches and different amb plating ( pentagona is quadrigeminate adapically).
- Diplopodia hilli: Clark (1893) described tubercles as widely separated with intervening space covered by small secondaries; D. doliae lacks enlarged secondaries.
