Trochotiara lindarae (Thompson, 2020)
Plate: 6
Series: Upper Cretaceous Group: Taylor Formation: Ozan
Locale: North Sulfur River County: Fannin European Stage: Campanian
Length: 28.5 mm Height: 12.4 mm
Collector: Linda Farish
Holotype NPL 85080
Repository: Non-vertebrate Paleo. Lab., Univ. of Texas
HOLOTYPE INFO:
Holotype: NPL 85080 (Thompson, 2020).
Locality: North Sulphur River, Fannin County, Texas.
Stratigraphy: Ozan Formation, Taylor Group.
SYNONYMY
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: Polydiadematidae Lambert, 1900
Genus: TROCHOTIARA Lambert, 1901
Species: Trochotiara lindarae (Thompson, 2020)
TYPE SPECIES: Diadema prisca Agassiz, 1840
DIAGNOSIS
A depressed, sub-pentagonal Trochotiara with large primary tubercles that continue to both poles (distinct from Allomma) and are clearly perforated (distinct from Gauthieria). Ambulacral pores are uniserial with a slight zigzag pattern; plating is quinqueminate (5 pairs per plate).
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Taylor; Navarro; Austin.
Formations: Ozan Formation; Unknown Navarro/Austin Formation (Travis Co.).
Stratigraphic Units: Upper Cretaceous, Campanian/Maastrichtian.
Counties: Fannin, Travis.
Abundance: Rare.
Distribution Notes: The specimen found by Linda Farish is from the Ozan Formation (Fannin Co.). The specimen found by Marc Vries comes from a quarry in south Austin (Travis Co.) where the exact formation is unknown; while many echinoids in this quarry are from the Navarro Group (Maastrichtian), Conulus stephensoni echinoids (Austin Chalk) are also found there. Additionally, crushed smaller specimens have been recovered from the Ozan Formation in North Travis County by Benjamin Tyler Stovich.
DESCRIPTION
TOP: Length, width, height: 28.5 mm L × 12.4 mm H. Top shape: Round, sub-pentagonal. Top domed: Weakly domed.
SIDE: Ambitus: Positioned at midpoint. Side shape: Depressed.
BOTTOM: Bottom shape: Flat.
AMB: Amb shape: Lanceolate; widest at ambitus, narrow at apical system and peristome. Amb arrangement: One primary tubercle on each plate. Width: Interambulacra are slightly wider than ambulacra at the ambitus. Plating: 5 pore pairs to each ambulacral plate (quinqueminate).
PORE PAIRS: Arrangement: Uniserial with a slight zigzag pattern. Shape: Round; pores below the ambitus are small and oblique; pores above the ambitus are larger and horizontal.
TUBERCLES: Primary Perforated: Yes (Clearly perforated near ambitus and below; faintly perforate near apical system). Primary Crenulate: Yes. Bosses: Striated. Distribution: Ambulacral and interambulacral tubercles are equal in size; largest at ambitus, reducing in size nearing apical system and peristome.
GRANULES: Distribution: Granulation at interradial, adradial, and perradial sutures.
FASCIOLE: [Absent].
INTERAMB: Arrangement: One primary tubercle on each plate.
APICAL SYSTEM: Size: Large apical scar; diameter 50% of test width. Shape: Star-shaped; cuts very deeply into interambulacra. Condition: Plating caducous (lost), presumed monocyclic.
PERIPROCT (ANUS): [Unknown].
PERISTOME (MOUTH): Size: Diameter 33% (1/3) of test. Shape: Sunken. Lip: Buccal notches small. No sphaeridial pits. No phyllodes.
SPINES: Unknown.
SPECIMENS STUDIED & CONDITION: Three perfect specimens and additional crushed material. Holotype NPL 85080 (Fannin Co.); one specimen found by Jordan Lee (Fannin Co.); one specimen found by Marc Vries (South Travis Co.); crushed smaller specimens found by Benjamin Tyler Stovich (North Travis Co.).
ETYMOLOGY
Named after Linda Rae Farish of Dallas, Texas, who found the Holotype.
REMARKS & COMPARISONS
Remarks: This species was originally described as Allomma lindarae. It is reassigned here to Trochotiara because Allomma is characterized by a lack of primary tubercles on the adoral surface, whereas T. lindarae maintains large tubercles to the poles. The presence of perforate tubercles excludes it from Gauthieria.
Comparisons:
Plate: 6
Series: Upper Cretaceous Group: Taylor Formation: Ozan
Locale: North Sulfur River County: Fannin European Stage: Campanian
Length: 28.5 mm Height: 12.4 mm
Collector: Linda Farish
Holotype NPL 85080
Repository: Non-vertebrate Paleo. Lab., Univ. of Texas
HOLOTYPE INFO:
Holotype: NPL 85080 (Thompson, 2020).
Locality: North Sulphur River, Fannin County, Texas.
Stratigraphy: Ozan Formation, Taylor Group.
SYNONYMY
- Gautheria sp. (Morgan, 2016)
- Gautheria sp. (Thompson, 2016)
- Allomma lindarae Thompson, 2020 [Original Combination]
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: Polydiadematidae Lambert, 1900
Genus: TROCHOTIARA Lambert, 1901
Species: Trochotiara lindarae (Thompson, 2020)
TYPE SPECIES: Diadema prisca Agassiz, 1840
DIAGNOSIS
A depressed, sub-pentagonal Trochotiara with large primary tubercles that continue to both poles (distinct from Allomma) and are clearly perforated (distinct from Gauthieria). Ambulacral pores are uniserial with a slight zigzag pattern; plating is quinqueminate (5 pairs per plate).
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Taylor; Navarro; Austin.
Formations: Ozan Formation; Unknown Navarro/Austin Formation (Travis Co.).
Stratigraphic Units: Upper Cretaceous, Campanian/Maastrichtian.
Counties: Fannin, Travis.
Abundance: Rare.
Distribution Notes: The specimen found by Linda Farish is from the Ozan Formation (Fannin Co.). The specimen found by Marc Vries comes from a quarry in south Austin (Travis Co.) where the exact formation is unknown; while many echinoids in this quarry are from the Navarro Group (Maastrichtian), Conulus stephensoni echinoids (Austin Chalk) are also found there. Additionally, crushed smaller specimens have been recovered from the Ozan Formation in North Travis County by Benjamin Tyler Stovich.
DESCRIPTION
TOP: Length, width, height: 28.5 mm L × 12.4 mm H. Top shape: Round, sub-pentagonal. Top domed: Weakly domed.
SIDE: Ambitus: Positioned at midpoint. Side shape: Depressed.
BOTTOM: Bottom shape: Flat.
AMB: Amb shape: Lanceolate; widest at ambitus, narrow at apical system and peristome. Amb arrangement: One primary tubercle on each plate. Width: Interambulacra are slightly wider than ambulacra at the ambitus. Plating: 5 pore pairs to each ambulacral plate (quinqueminate).
PORE PAIRS: Arrangement: Uniserial with a slight zigzag pattern. Shape: Round; pores below the ambitus are small and oblique; pores above the ambitus are larger and horizontal.
TUBERCLES: Primary Perforated: Yes (Clearly perforated near ambitus and below; faintly perforate near apical system). Primary Crenulate: Yes. Bosses: Striated. Distribution: Ambulacral and interambulacral tubercles are equal in size; largest at ambitus, reducing in size nearing apical system and peristome.
GRANULES: Distribution: Granulation at interradial, adradial, and perradial sutures.
FASCIOLE: [Absent].
INTERAMB: Arrangement: One primary tubercle on each plate.
APICAL SYSTEM: Size: Large apical scar; diameter 50% of test width. Shape: Star-shaped; cuts very deeply into interambulacra. Condition: Plating caducous (lost), presumed monocyclic.
PERIPROCT (ANUS): [Unknown].
PERISTOME (MOUTH): Size: Diameter 33% (1/3) of test. Shape: Sunken. Lip: Buccal notches small. No sphaeridial pits. No phyllodes.
SPINES: Unknown.
SPECIMENS STUDIED & CONDITION: Three perfect specimens and additional crushed material. Holotype NPL 85080 (Fannin Co.); one specimen found by Jordan Lee (Fannin Co.); one specimen found by Marc Vries (South Travis Co.); crushed smaller specimens found by Benjamin Tyler Stovich (North Travis Co.).
ETYMOLOGY
Named after Linda Rae Farish of Dallas, Texas, who found the Holotype.
REMARKS & COMPARISONS
Remarks: This species was originally described as Allomma lindarae. It is reassigned here to Trochotiara because Allomma is characterized by a lack of primary tubercles on the adoral surface, whereas T. lindarae maintains large tubercles to the poles. The presence of perforate tubercles excludes it from Gauthieria.
Comparisons:
- Trochotiara bonei: The Type Species shares the pentagonal, depressed test and 5-pair compound plating of T. lindarae.
