Elliptechinus kiwiaster Schneider, Sprinkle & Ryder, 2005
Plate: ElKi-10
Series: Pennsylvanian Group: Canyon Formation: Winchell (formerly Graford)
Locale: Brownwood County: Brown Stage: Kasimovian
Length: 52.5 mm Width: 34.0 mm
Specimen in photo: TMM 1967TX24 (Paratype)
Repository: Non-vertebrate Paleo. Lab., Univ. of Texas
HOLOTYPE INFO:
Holotype: TMM 1967TX22 — Non-vertebrate Paleontology Laboratory, Texas Memorial Museum, University of Texas (Schneider et al., 2005)
Locality: Lake Brownwood Spillway, Brown County, Texas (Schneider et al., 2005)
SYSTEMATIC PALEONTOLOGY – TAXONOMY
Class: Echinoidea Leske, 1778
Subclass: Perischoechinoidea M'Coy, 1849
Order: Echinocystitoida Jackson, 1912
Family: Lepidesthidae Jackson, 1896
Genus: ELLIPTECHINUS Schneider, Sprinkle & Ryder, 2005
Species: Elliptechinus kiwiaster Schneider, Sprinkle & Ryder, 2005
TYPE SPECIES: Elliptechinus kiwiaster Schneider, Sprinkle & Ryder, 2005 (Monotypic)
DIAGNOSIS
Test ellipsoidal, egg-shaped. Ambulacra narrow, biserial; plates interlocking (zipper-like). Interambulacra wide, composed of numerous columns of hexagonal plates. Spines short, dense, and acicular (Schneider et al., 2005).
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Canyon (Schneider et al., 2005)
Formations: Winchell Formation (formerly mapped as Graford Formation) (Schneider et al., 2005)
Stratigraphic Units: Pennsylvanian, Kasimovian (Missourian) (Schneider et al., 2005)
Counties: Brown County
DESCRIPTION
TOP: Length, width, height: 52.5 mm L × 34.0 mm H
Top shape: Oval, egg-shaped (ellipsoidal)
AMB: Amb shape: Relatively straight
Amb plating: Plates very small compared to interamb plates; hourglass-shaped plates intermingle like a zipper
Amb arrangement: Biserial (two columns); every plate has a tubercle
Amb granules: Small granule on every other plate
INTERAMB: Interamb width: Much wider than ambulacra
Interamb plate shape: Sub-hexagonal
Interamb primary tubercles: 3 tubercles on each plate
Arrangement: Plates in each column staggered, forming diagonal rows
PORE PAIRS: Shape: Slightly tear-drop shaped
Arrangement: Biserial
TUBERCLES: Primary Perforated: Yes (Schneider et al., 2005)
Primary Crenulate: No (Schneider et al., 2005)
Primary Areola shape: Relatively large, smooth, slightly sunken
Primary Boss: Slightly raised from plate surface
APICAL SYSTEM: Unknown
PERIPROCT (ANUS): Unknown
PERISTOME (MOUTH): Unknown
SPINES: Shape: Small, fine, smooth; Short, acicular (Schneider et al., 2005)
Widest location: At collar
SPECIMENS STUDIED & CONDITION
Paratype TMM 1967TX24 .
ETYMOLOGY: Named kiwiaster for the test's resemblance in size and shape to a kiwi fruit (Actinidia deliciosa) + Greek aster (star/echinoid) (Schneider et al., 2005).
REMARKS & COMPARISONS
Remarks: Elliptechinus is a Lepidesthid, a family usually characterized by having ambulacra with many columns of plates (up to 20 in some genera). Elliptechinus is unique (or primitive) in retaining a simple biserial (2-column) ambulacral arrangement while having the multi-columned interambulacra typical of the order. The "zipper-like" amb plates described by Thompson correspond to the alternating biserial plates described by Schneider et al. (2005).
Plate: ElKi-10
Series: Pennsylvanian Group: Canyon Formation: Winchell (formerly Graford)
Locale: Brownwood County: Brown Stage: Kasimovian
Length: 52.5 mm Width: 34.0 mm
Specimen in photo: TMM 1967TX24 (Paratype)
Repository: Non-vertebrate Paleo. Lab., Univ. of Texas
HOLOTYPE INFO:
Holotype: TMM 1967TX22 — Non-vertebrate Paleontology Laboratory, Texas Memorial Museum, University of Texas (Schneider et al., 2005)
Locality: Lake Brownwood Spillway, Brown County, Texas (Schneider et al., 2005)
SYSTEMATIC PALEONTOLOGY – TAXONOMY
Class: Echinoidea Leske, 1778
Subclass: Perischoechinoidea M'Coy, 1849
Order: Echinocystitoida Jackson, 1912
Family: Lepidesthidae Jackson, 1896
Genus: ELLIPTECHINUS Schneider, Sprinkle & Ryder, 2005
Species: Elliptechinus kiwiaster Schneider, Sprinkle & Ryder, 2005
TYPE SPECIES: Elliptechinus kiwiaster Schneider, Sprinkle & Ryder, 2005 (Monotypic)
DIAGNOSIS
Test ellipsoidal, egg-shaped. Ambulacra narrow, biserial; plates interlocking (zipper-like). Interambulacra wide, composed of numerous columns of hexagonal plates. Spines short, dense, and acicular (Schneider et al., 2005).
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Canyon (Schneider et al., 2005)
Formations: Winchell Formation (formerly mapped as Graford Formation) (Schneider et al., 2005)
Stratigraphic Units: Pennsylvanian, Kasimovian (Missourian) (Schneider et al., 2005)
Counties: Brown County
DESCRIPTION
TOP: Length, width, height: 52.5 mm L × 34.0 mm H
Top shape: Oval, egg-shaped (ellipsoidal)
AMB: Amb shape: Relatively straight
Amb plating: Plates very small compared to interamb plates; hourglass-shaped plates intermingle like a zipper
Amb arrangement: Biserial (two columns); every plate has a tubercle
Amb granules: Small granule on every other plate
INTERAMB: Interamb width: Much wider than ambulacra
Interamb plate shape: Sub-hexagonal
Interamb primary tubercles: 3 tubercles on each plate
Arrangement: Plates in each column staggered, forming diagonal rows
PORE PAIRS: Shape: Slightly tear-drop shaped
Arrangement: Biserial
TUBERCLES: Primary Perforated: Yes (Schneider et al., 2005)
Primary Crenulate: No (Schneider et al., 2005)
Primary Areola shape: Relatively large, smooth, slightly sunken
Primary Boss: Slightly raised from plate surface
APICAL SYSTEM: Unknown
PERIPROCT (ANUS): Unknown
PERISTOME (MOUTH): Unknown
SPINES: Shape: Small, fine, smooth; Short, acicular (Schneider et al., 2005)
Widest location: At collar
SPECIMENS STUDIED & CONDITION
Paratype TMM 1967TX24 .
ETYMOLOGY: Named kiwiaster for the test's resemblance in size and shape to a kiwi fruit (Actinidia deliciosa) + Greek aster (star/echinoid) (Schneider et al., 2005).
REMARKS & COMPARISONS
Remarks: Elliptechinus is a Lepidesthid, a family usually characterized by having ambulacra with many columns of plates (up to 20 in some genera). Elliptechinus is unique (or primitive) in retaining a simple biserial (2-column) ambulacral arrangement while having the multi-columned interambulacra typical of the order. The "zipper-like" amb plates described by Thompson correspond to the alternating biserial plates described by Schneider et al. (2005).
