Cosmocyphus leanderensis Thompson, 2020
Plate: CoLe-10
Series: Lower Cretaceous Group: Fredericksburg Formation: Edwards
Locale: Cedar Park County: Travis Stage: Albian
Length: 48.1 mm Height: 24.7 mm
Collection: Dr. Steven Crane
Repository: Non-vertebrate Paleo. Lab., Univ. of Texas
HOLOTYPE INFO:
Holotype: NPL 94315 — Non-vertebrate Paleontology Laboratory, University of Texas
Paratype: NPL 94316
Locality: Quarry in Cedar Park, Travis 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: Phymosomatidae Pomel, 1883
Genus: COSMOCYPHUS Pomel, 1883
Species: Cosmocyphus leanderensis Thompson, 2020
TYPE SPECIES: Cyphosoma saemanni Coquand, 1860
DIAGNOSIS
A large inflated Cosmocyphus from the Lower Cretaceous of central Texas, Fredericksburg Group, Edwards Formation with high domed apical area, pore pairs uniserial touching the apical system, then immediately biserial to just below ambitus and uniserial below. Below ambitus and on adoral surface, each interambulacral tubercle has 5 striations, crossing each boss, over the areola and between the pore pairs .
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Fredericksburg
Formations: Edwards Formation
Stratigraphic Units: Lower Cretaceous, Albian
Counties: Travis County
DESCRIPTION
TOP: Length, height: 48.1 mm L × 24.7 mm H
Top shape: Round from above
Top domed: High domed apical area; Apical area swollen
SIDE: Ambitus: 50% from adoral side
Side shape: Rounded; flat top and bottom
BOTTOM: Bottom shape: Adoral surface depressed
AMB: Amb shape: Lanceolate, pointed at both ends, widest at ambitus
Amb width: 39% of Interambulacral width at ambitus
Amb primary tubercles: Two rows, 18 per row; reducing in size near poles
Amb arrangement: Pore pairs uniserial for first 6–8 pairs at apical scar; biserial to just below ambitus (composed of 6 elements); uniserial on adoral surface (composed of 4–5 elements with pore pairs in arcs)
INTERAMB: Interamb primary tubercles: Four rows of tubercles slightly larger than ambulacral; 12 on inside rows, 7 on outer rows; gradually diminishing aborally and missing adapically
Interamb plating: Plates much wider than tall
Granules: Rows of granules zigzag at adradial and interradial margins on oral surface to above ambitus
TUBERCLES: Primary tubercles: Single primary tubercle to each ambulacral plate, centrally located. Medium size .
Primary Perforated: Yes
Primary Crenulate: Yes
Primary Mamelon: Large
Ornamentation: On the aboral surface, each interambulacral tubercle has 5 striations crossing lower half of boss and areola, sloping away and between pore pairs .
APICAL SYSTEM: Size: 40% of test
Shape: Angular, pentagonal; apical scar sunken at interambulacral areas and swollen at ambulacral areas
Condition: Plating lost
PERIPROCT (ANUS): Condition: Unknown
PERISTOME (MOUTH): Size: 46% diameter of test
Shape: Subpentagonal; angular
Lip: Lips small
Sunken: Depressed
SPECIMENS STUDIED & CONDITION
Specimen condition: Three specimens studied. Holotype NPL 94315 .
ETYMOLOGY: Named after the city near where the species was found – Leander, Texas .
REMARKS & COMPARISONS
Remarks: Cosmocyphus leanderensis shares similar (though slightly less pronounced) striations with C. rugosum and C. krameri.
Comparisons: C. krameri: C. leanderensis has smaller tubercles and a swollen apical area (unlike krameri). Unique Feature: The pore pair sequence (Uniserial at apex -> Biserial -> Uniserial below) is noted as unique .
Plate: CoLe-10
Series: Lower Cretaceous Group: Fredericksburg Formation: Edwards
Locale: Cedar Park County: Travis Stage: Albian
Length: 48.1 mm Height: 24.7 mm
Collection: Dr. Steven Crane
Repository: Non-vertebrate Paleo. Lab., Univ. of Texas
HOLOTYPE INFO:
Holotype: NPL 94315 — Non-vertebrate Paleontology Laboratory, University of Texas
Paratype: NPL 94316
Locality: Quarry in Cedar Park, Travis 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: Phymosomatidae Pomel, 1883
Genus: COSMOCYPHUS Pomel, 1883
Species: Cosmocyphus leanderensis Thompson, 2020
TYPE SPECIES: Cyphosoma saemanni Coquand, 1860
DIAGNOSIS
A large inflated Cosmocyphus from the Lower Cretaceous of central Texas, Fredericksburg Group, Edwards Formation with high domed apical area, pore pairs uniserial touching the apical system, then immediately biserial to just below ambitus and uniserial below. Below ambitus and on adoral surface, each interambulacral tubercle has 5 striations, crossing each boss, over the areola and between the pore pairs .
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Fredericksburg
Formations: Edwards Formation
Stratigraphic Units: Lower Cretaceous, Albian
Counties: Travis County
DESCRIPTION
TOP: Length, height: 48.1 mm L × 24.7 mm H
Top shape: Round from above
Top domed: High domed apical area; Apical area swollen
SIDE: Ambitus: 50% from adoral side
Side shape: Rounded; flat top and bottom
BOTTOM: Bottom shape: Adoral surface depressed
AMB: Amb shape: Lanceolate, pointed at both ends, widest at ambitus
Amb width: 39% of Interambulacral width at ambitus
Amb primary tubercles: Two rows, 18 per row; reducing in size near poles
Amb arrangement: Pore pairs uniserial for first 6–8 pairs at apical scar; biserial to just below ambitus (composed of 6 elements); uniserial on adoral surface (composed of 4–5 elements with pore pairs in arcs)
INTERAMB: Interamb primary tubercles: Four rows of tubercles slightly larger than ambulacral; 12 on inside rows, 7 on outer rows; gradually diminishing aborally and missing adapically
Interamb plating: Plates much wider than tall
Granules: Rows of granules zigzag at adradial and interradial margins on oral surface to above ambitus
TUBERCLES: Primary tubercles: Single primary tubercle to each ambulacral plate, centrally located. Medium size .
Primary Perforated: Yes
Primary Crenulate: Yes
Primary Mamelon: Large
Ornamentation: On the aboral surface, each interambulacral tubercle has 5 striations crossing lower half of boss and areola, sloping away and between pore pairs .
APICAL SYSTEM: Size: 40% of test
Shape: Angular, pentagonal; apical scar sunken at interambulacral areas and swollen at ambulacral areas
Condition: Plating lost
PERIPROCT (ANUS): Condition: Unknown
PERISTOME (MOUTH): Size: 46% diameter of test
Shape: Subpentagonal; angular
Lip: Lips small
Sunken: Depressed
SPECIMENS STUDIED & CONDITION
Specimen condition: Three specimens studied. Holotype NPL 94315 .
ETYMOLOGY: Named after the city near where the species was found – Leander, Texas .
REMARKS & COMPARISONS
Remarks: Cosmocyphus leanderensis shares similar (though slightly less pronounced) striations with C. rugosum and C. krameri.
Comparisons: C. krameri: C. leanderensis has smaller tubercles and a swollen apical area (unlike krameri). Unique Feature: The pore pair sequence (Uniserial at apex -> Biserial -> Uniserial below) is noted as unique .
