Leptosalenia texana (Credner, 1875)
Plate: LeTe-10
Series: Lower Cretaceous Group: Trinity Formation: Glen Rose
Locale: Smith Branch County: Comal Stage: Albian
Length: 24.1 mm Height: 16.6 mm
Specimen in photo: NPL 83021 Hypotype
Collector: William R. Thompson, Jr.
Repository: Non-vertebrate Paleo. Lab., Univ. of Texas
Plate: LeTe-20
Series: Lower Cretaceous Group: Trinity Formation: Glen Rose
Locale: Canyon Lake County: Comal Stage: Albian
Length: 28.1 mm Height: 2.7 mm
Specimen in photo: NPL 83022 Hypotype
Collector: William R. Thompson, Jr.
Repository: Non-vertebrate Paleo. Lab., Univ. of Texas
HOLOTYPE INFO:
Holotype: Credner's original material. Repository uncertain (possibly University of Leipzig or Berlin).
Locality: Texas (Credner, 1875).
Stratigraphy: Cretaceous.
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 texana (Credner, 1875)
TYPE SPECIES: Salenia prestensis Desor, 1856
DIAGNOSIS
Test subglobose with a strongly convex to conical apical system. Ambulacra narrow and flexuous. Interambulacra formed of two rows of six plates. Apical system large with radiating ridges on genital plates and distinct sutural pitting; genital plates II and III typically surrounded by 9 pits (Smith & Rader, 2009).
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Trinity; Fredericksburg/Washita (Clark & Twitchell, 1915).
Formations: Glen Rose Formation.
Stratigraphic Units: Lower Cretaceous, Albian.
Counties: Comal.
Abundance: Common in the Glen Rose Formation.
DESCRIPTION
TOP: Length, width, height: 24.1 mm L × 16.6 mm H (Test, NPL 83021).
Top shape: Subcircular (Clark & Twitchell, 1915).
Top domed: Upper surface convex; apical system is very large and convex/conical.
SIDE: Ambitus: Inflated, presenting a rounded surface which is fuller above than below (Clark & Twitchell, 1915).
Side shape: Subspherical when complete; sometimes flattened.
BOTTOM: Bottom shape: Under surface flat; slightly concave in the vicinity of the peristome (Clark & Twitchell, 1915).
AMB: Amb shape: Narrow, increasing gradually in width from the apical system to the peristome. Poriferous zones are narrow and flexuous; the most pronounced flexure is opposite the second interambulacral plate from the apical system (Clark & Twitchell, 1915).
Amb arrangement: Two rows of mammillated granules (24 to 26 in each) occupy the middle of each area.
PORE PAIRS: Arrangement: Uniserial; regularly arranged. Slightly more crowded near the peristome (Clark & Twitchell, 1915).
TUBERCLES: Primary Perforated: No (Imperforate).
Primary Crenulate: Yes; boss is deeply crenulated (Clark & Twitchell, 1915).
Interambulacral Tubercles: Two alternating rows of broad plates, six in each row. Tubercles increase rapidly in size from the peristome.
Areolas: Large; surrounded by mammillated granules crowded along the inner edge of the plates (Clark & Twitchell, 1915).
GRANULES: Distribution: Very minute granules extend in a line between the ambulacral rows. Numerous minute granules located between the larger interambulacral granules (Clark & Twitchell, 1915).
FASCIOLE: Absent.
APICAL SYSTEM: Size: Very large.
Shape: Convex/conical (distinctly cone-shaped per Smith & Rader, 2009).
Ornamentation: Radiating ridges extend from the ovarial openings of each plate and unite with ridges of adjacent plates. Small punctures (sutural pits) are found at the angles of the plates and intermediate between them (Clark & Twitchell, 1915). Typically, 9 sutural pits surround Genital plates II and III (Smith & Rader, 2009).
Plating: Subanal plate (suranal) occupies the center of the disk.
PERIPROCT (ANUS): Shape: Subelliptical to triangular; rounded towards margin, angular towards center.
Features: Slightly elevated at the border (Clark & Twitchell, 1915).
PERISTOME (MOUTH): Size: Large; covering nearly one-half the diameter of the test.
Shape: Circular with ten incisions (buccal notches) dividing it into equal-sized lobes (Clark & Twitchell, 1915).
SPINES: Shape: Tapered with smooth sides. The shaft's widest point is near the collar, narrowing just before the collar.
Features: Collar is pronounced with striations towards the end.
Base: Rounded and perforated with a ring of small bumps (Book Author).
SPECIMENS STUDIED & CONDITION:
ETYMOLOGY
Named for the state of Texas, the type locality.
REMARKS & COMPARISONS
Remarks: Smith & Rader (2009) discussed the variations of Leptosalenia in the Glen Rose Formation, noting that L. texana is characterized by its strongly conical apical system and high number of sutural pits (9) on specific genital plates, distinguishing it from related forms like L. smithi (which has a flat apical system).
Plate: LeTe-10
Series: Lower Cretaceous Group: Trinity Formation: Glen Rose
Locale: Smith Branch County: Comal Stage: Albian
Length: 24.1 mm Height: 16.6 mm
Specimen in photo: NPL 83021 Hypotype
Collector: William R. Thompson, Jr.
Repository: Non-vertebrate Paleo. Lab., Univ. of Texas
Plate: LeTe-20
Series: Lower Cretaceous Group: Trinity Formation: Glen Rose
Locale: Canyon Lake County: Comal Stage: Albian
Length: 28.1 mm Height: 2.7 mm
Specimen in photo: NPL 83022 Hypotype
Collector: William R. Thompson, Jr.
Repository: Non-vertebrate Paleo. Lab., Univ. of Texas
HOLOTYPE INFO:
Holotype: Credner's original material. Repository uncertain (possibly University of Leipzig or Berlin).
Locality: Texas (Credner, 1875).
Stratigraphy: Cretaceous.
SYNONYMY
- Salenia texana Credner, 1875
- Leptosalenia texana (Credner, 1875) (assigned by Smith & Wright, 1990)
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 texana (Credner, 1875)
TYPE SPECIES: Salenia prestensis Desor, 1856
DIAGNOSIS
Test subglobose with a strongly convex to conical apical system. Ambulacra narrow and flexuous. Interambulacra formed of two rows of six plates. Apical system large with radiating ridges on genital plates and distinct sutural pitting; genital plates II and III typically surrounded by 9 pits (Smith & Rader, 2009).
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Trinity; Fredericksburg/Washita (Clark & Twitchell, 1915).
Formations: Glen Rose Formation.
Stratigraphic Units: Lower Cretaceous, Albian.
Counties: Comal.
Abundance: Common in the Glen Rose Formation.
DESCRIPTION
TOP: Length, width, height: 24.1 mm L × 16.6 mm H (Test, NPL 83021).
Top shape: Subcircular (Clark & Twitchell, 1915).
Top domed: Upper surface convex; apical system is very large and convex/conical.
SIDE: Ambitus: Inflated, presenting a rounded surface which is fuller above than below (Clark & Twitchell, 1915).
Side shape: Subspherical when complete; sometimes flattened.
BOTTOM: Bottom shape: Under surface flat; slightly concave in the vicinity of the peristome (Clark & Twitchell, 1915).
AMB: Amb shape: Narrow, increasing gradually in width from the apical system to the peristome. Poriferous zones are narrow and flexuous; the most pronounced flexure is opposite the second interambulacral plate from the apical system (Clark & Twitchell, 1915).
Amb arrangement: Two rows of mammillated granules (24 to 26 in each) occupy the middle of each area.
PORE PAIRS: Arrangement: Uniserial; regularly arranged. Slightly more crowded near the peristome (Clark & Twitchell, 1915).
TUBERCLES: Primary Perforated: No (Imperforate).
Primary Crenulate: Yes; boss is deeply crenulated (Clark & Twitchell, 1915).
Interambulacral Tubercles: Two alternating rows of broad plates, six in each row. Tubercles increase rapidly in size from the peristome.
Areolas: Large; surrounded by mammillated granules crowded along the inner edge of the plates (Clark & Twitchell, 1915).
GRANULES: Distribution: Very minute granules extend in a line between the ambulacral rows. Numerous minute granules located between the larger interambulacral granules (Clark & Twitchell, 1915).
FASCIOLE: Absent.
APICAL SYSTEM: Size: Very large.
Shape: Convex/conical (distinctly cone-shaped per Smith & Rader, 2009).
Ornamentation: Radiating ridges extend from the ovarial openings of each plate and unite with ridges of adjacent plates. Small punctures (sutural pits) are found at the angles of the plates and intermediate between them (Clark & Twitchell, 1915). Typically, 9 sutural pits surround Genital plates II and III (Smith & Rader, 2009).
Plating: Subanal plate (suranal) occupies the center of the disk.
PERIPROCT (ANUS): Shape: Subelliptical to triangular; rounded towards margin, angular towards center.
Features: Slightly elevated at the border (Clark & Twitchell, 1915).
PERISTOME (MOUTH): Size: Large; covering nearly one-half the diameter of the test.
Shape: Circular with ten incisions (buccal notches) dividing it into equal-sized lobes (Clark & Twitchell, 1915).
SPINES: Shape: Tapered with smooth sides. The shaft's widest point is near the collar, narrowing just before the collar.
Features: Collar is pronounced with striations towards the end.
Base: Rounded and perforated with a ring of small bumps (Book Author).
SPECIMENS STUDIED & CONDITION:
- Hypotype NPL 83021: Test (24.1 mm). Collected at Smith Branch.
- Hypotype NPL 83022: Isolated spine (Length 28.1 mm). Collected at Canyon Lake.
ETYMOLOGY
Named for the state of Texas, the type locality.
REMARKS & COMPARISONS
Remarks: Smith & Rader (2009) discussed the variations of Leptosalenia in the Glen Rose Formation, noting that L. texana is characterized by its strongly conical apical system and high number of sutural pits (9) on specific genital plates, distinguishing it from related forms like L. smithi (which has a flat apical system).
