Leptosalenia mexicana (Schluter, 1887)
Plate: LeMe-10
Series: Lower Cretaceous Group: Fredericksburg Formation: Comanche Peak
Locale: Goldthwaite County: Mills Stage: Albian
Length: 11.1 mm Height: 6.9 mm
Specimen in photo: NPL 83020 Hypotype
Collector: William R. Thompson, Jr.
Repository: Non-vertebrate Paleo. Lab., Univ. of Texas
HOLOTYPE INFO:
Holotype: Described by Schlüter (1887). Repository likely in Bonn, Germany (Goldfuss Museum).
Locality: Texas (Schlüter, 1887).
Stratigraphy: Fredericksburg Group.
SYNONYMY
SYSTEMATIC PALEONTOLOGY – TAXONOMY
Class: Echinoidea Leske, 1778
Subclass: Euechinoidea Bronn, 1860
Infraclass: Carinacea Kroh & Smith, 2010
Superorder: Calycina Gregory, 1900
Order: Salenioida Delage & Hérouard, 1903
Family: Saleniidae L. Agassiz, 1838
Genus: LEPTOSALENIA Smith & Wright, 1990
Species: Leptosalenia mexicana (Schlüter, 1887)
TYPE SPECIES: Salenia prestensis Desor, 1856
DIAGNOSIS
Test small, nearly globose; upper surface convex with a conspicuous, raised apical cap; under surface concave. Interambulacra consist of two alternating rows of large angular plates bearing prominent tubercles. Distinguished from L. texana by its typically smaller size (Adkins & Winton, 1919).
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Fredericksburg
Formations: Comanche Peak Limestone; Goodland Limestone (Upper Salenia horizon, 26-32 feet below top); rare in basal Duck Creek and Pawpaw (Adkins & Winton, 1919).
Stratigraphic Units: Lower Cretaceous, Albian.
Counties: Mills, Tarrant.
Abundance: Abundant in specific zones of the Goodland/Comanche Peak (Adkins & Winton, 1919).
DESCRIPTION
TOP: Length, width, height: 11.1 mm L × 6.9 mm H.
Top shape: Circular outline.
Top domed: Very inflated; upper surface convex bearing a conspicuous cap (Adkins & Winton, 1919).
SIDE: Ambitus: Positioned 40% of height from the base.
Side shape: Sides inflated; consists of large plates (Adkins & Winton, 1919). Apical disc raised and inflated.
BOTTOM: Bottom shape: Concave (Adkins & Winton, 1919); flat to slightly convex in studied specimen.
AMB: Amb shape: Narrow; sinuous near the apical disc, straight from ambitus to peristome. Narrowest at apical disc, widest at peristome.
Amb arrangement:. Two rows of staggered tubercles. Flexuous with two rows of small rounded granules (Adkins & Winton, 1919).
PORE PAIRS: Arrangement: Uniserial.
Elements: Bigeminate.
TUBERCLES: Primary Perforated: No Imperforate.
Primary Crenulate: Yes.
Interambulacral Tubercles: Two alternating rows, each with six large angular plates bearing prominent tubercles (Adkins & Winton, 1919). In the studied specimen, one tubercle in each row is much larger than the others.
Scrobicular Tubercles: Surround interambulacral tubercles; naked at the adradial suture.
GRANULES: Flexuous with two rows of small rounded granules (Adkins & Winton, 1919).
FASCIOLE: Absent.
APICAL SYSTEM: Size: Prominent; diameter 65% of test diameter.
Shape: Round, highly domed; raised 30% above the test.
Genital Pores: 5 gonopores.
PERIPROCT (ANUS): Shape: Sub-pentagonal; wider than tall.
Size: Diameter is 23% of the apical system.
PERISTOME (MOUTH): Size: Diameter 50% of test.
Lip: Prominent buccal notches.
SPINES: Unknown.
SPECIMENS STUDIED & CONDITION: Hypotype NPL 83020.
ETYMOLOGY
Named for Mexico (or the proximity of the Texas Cretaceous province to Mexico), as defined by Schlüter (1887).
REMARKS & COMPARISONS
Comparisons:
Plate: LeMe-10
Series: Lower Cretaceous Group: Fredericksburg Formation: Comanche Peak
Locale: Goldthwaite County: Mills Stage: Albian
Length: 11.1 mm Height: 6.9 mm
Specimen in photo: NPL 83020 Hypotype
Collector: William R. Thompson, Jr.
Repository: Non-vertebrate Paleo. Lab., Univ. of Texas
HOLOTYPE INFO:
Holotype: Described by Schlüter (1887). Repository likely in Bonn, Germany (Goldfuss Museum).
Locality: Texas (Schlüter, 1887).
Stratigraphy: Fredericksburg Group.
SYNONYMY
- Salenia mexicana Schlüter, 1887
SYSTEMATIC PALEONTOLOGY – TAXONOMY
Class: Echinoidea Leske, 1778
Subclass: Euechinoidea Bronn, 1860
Infraclass: Carinacea Kroh & Smith, 2010
Superorder: Calycina Gregory, 1900
Order: Salenioida Delage & Hérouard, 1903
Family: Saleniidae L. Agassiz, 1838
Genus: LEPTOSALENIA Smith & Wright, 1990
Species: Leptosalenia mexicana (Schlüter, 1887)
TYPE SPECIES: Salenia prestensis Desor, 1856
DIAGNOSIS
Test small, nearly globose; upper surface convex with a conspicuous, raised apical cap; under surface concave. Interambulacra consist of two alternating rows of large angular plates bearing prominent tubercles. Distinguished from L. texana by its typically smaller size (Adkins & Winton, 1919).
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Fredericksburg
Formations: Comanche Peak Limestone; Goodland Limestone (Upper Salenia horizon, 26-32 feet below top); rare in basal Duck Creek and Pawpaw (Adkins & Winton, 1919).
Stratigraphic Units: Lower Cretaceous, Albian.
Counties: Mills, Tarrant.
Abundance: Abundant in specific zones of the Goodland/Comanche Peak (Adkins & Winton, 1919).
DESCRIPTION
TOP: Length, width, height: 11.1 mm L × 6.9 mm H.
Top shape: Circular outline.
Top domed: Very inflated; upper surface convex bearing a conspicuous cap (Adkins & Winton, 1919).
SIDE: Ambitus: Positioned 40% of height from the base.
Side shape: Sides inflated; consists of large plates (Adkins & Winton, 1919). Apical disc raised and inflated.
BOTTOM: Bottom shape: Concave (Adkins & Winton, 1919); flat to slightly convex in studied specimen.
AMB: Amb shape: Narrow; sinuous near the apical disc, straight from ambitus to peristome. Narrowest at apical disc, widest at peristome.
Amb arrangement:. Two rows of staggered tubercles. Flexuous with two rows of small rounded granules (Adkins & Winton, 1919).
PORE PAIRS: Arrangement: Uniserial.
Elements: Bigeminate.
TUBERCLES: Primary Perforated: No Imperforate.
Primary Crenulate: Yes.
Interambulacral Tubercles: Two alternating rows, each with six large angular plates bearing prominent tubercles (Adkins & Winton, 1919). In the studied specimen, one tubercle in each row is much larger than the others.
Scrobicular Tubercles: Surround interambulacral tubercles; naked at the adradial suture.
GRANULES: Flexuous with two rows of small rounded granules (Adkins & Winton, 1919).
FASCIOLE: Absent.
APICAL SYSTEM: Size: Prominent; diameter 65% of test diameter.
Shape: Round, highly domed; raised 30% above the test.
Genital Pores: 5 gonopores.
PERIPROCT (ANUS): Shape: Sub-pentagonal; wider than tall.
Size: Diameter is 23% of the apical system.
PERISTOME (MOUTH): Size: Diameter 50% of test.
Lip: Prominent buccal notches.
SPINES: Unknown.
SPECIMENS STUDIED & CONDITION: Hypotype NPL 83020.
ETYMOLOGY
Named for Mexico (or the proximity of the Texas Cretaceous province to Mexico), as defined by Schlüter (1887).
REMARKS & COMPARISONS
Comparisons:
- Leptosalenia texana (Salenia texana): Adkins & Winton (1919) note that minute differences separate L. mexicana from L. texana. The average size of L. mexicana is less than that of L. texana, and L. mexicana is stated to come from a higher stratigraphic level.
- Leptosalenia volana (Salenia volana): Distinguished from this Upper Cenomanian species by stratigraphic level and minor morphological differences (Adkins & Winton, 1919).
