Salenia leanderensis Ikins, 1940
Plate: SaLe-10
Series: Lower Cretaceous Group: Trinity Formation: Glen Rose
Locale: Copperas Cove County: Coryell Stage: Albian
Length: 11.8 mm Height: 8.5 mm
Specimen in photos: Collection of Ed Elliott
Repository: Private Collection
HOLOTYPE INFO:
Holotype: UT 40537 (BEG 40537) (Ikins, 1940).
Locality: Borrow pit on west side of road, 1 mile north of Leander, Williamson County, Texas (Ikins, 1940).
Stratigraphy: Upper clays of Walnut Formation, 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: SALENIA Gray, 1835
Species: Salenia leanderensis Ikins, 1940
TYPE SPECIES: Cidaris scutigera Gray, 1835
DIAGNOSIS
Test circular and small (9 mm holotype). Ambulacra straight with two rows of about 12 imperforate, crenulate tubercles. Interambulacra composed of two rows of five plates. Apical disk circular and raised. Distinguished from S. mexicana by fewer ambulacral tubercles (12 vs 18–20) and fewer interambulacral plates (5 vs 6) (Ikins, 1940).
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Fredericksburg (Type); Trinity (Specimen).
Formations: Walnut Formation; Glen Rose Formation.
Stratigraphic Units: Lower Cretaceous, Albian.
Counties: Williamson (Type), Coryell.
Abundance: Rare.
DESCRIPTION
TOP: Length, width, height: 11.8 mm L × 8.5 mm H. Top shape: Subpentagonal (Book Author); circular in ambital outline (Ikins, 1940). Top domed: Abactinal surface gently and regularly rounded (Ikins, 1940). Prominent apical cap sits raised on the corona (Book Author).
SIDE: Ambitus: Positioned at midpoint between bottom and corona. Side shape: Slightly inflated (Ikins, 1940); sloping sides.
BOTTOM: Bottom shape: Adactinal surface practically flat (Ikins, 1940).
AMB: Amb shape: Quite straight and wide; widening only slightly between apical disk and peristome (Ikins, 1940). Book Author describes them as flexuous. Amb arrangement: About one-half the width of the interambulacra at the ambitus (Ikins, 1940). Two rows of tubercles are staggered between sets of pore pairs (Book Author).
PORE PAIRS: Arrangement: Unigeminal (Ikins, 1940); uniserial. Condition: Become irregular and crowded upon approaching the peristome (Ikins, 1940).
TUBERCLES: Primary Perforated: No (Imperforate). Primary Crenulate: Yes. Ambulacral Tubercles: Two alternating rows of about 12 tubercles (Ikins, 1940). Interambulacral Tubercles: Two rows of five plates; each plate ornamented with a scrobiculate boss bearing an imperforate, crenulate mamelon (Ikins, 1940). In studied specimen, two large and one smaller tubercle per row (Book Author).
GRANULES: Distribution: Ikins (1940) states "no granules between the tubercles" in the ambulacra. Book Author notes "granulation between sets of pore pairs." Interambulacral granules are arranged with one in the upper/lower adradial corners and five on the medial margin of each plate (Ikins, 1940).
FASCIOLE: Absent.
APICAL SYSTEM: Size: Large; diameter 6 mm in holotype (approx. 66%). Shape: Circular (Ikins, 1940) to pentagonal (Book Author). Raised above the surface. Plating: Oculars are triangular; genitals are perforated near the center. Ornamentation: Ikins (1940) noted "no ornamentation" on the type; Book Author notes genital plates have sutural pits at boundaries and midpoints.
PERIPROCT (ANUS): Shape: Slightly deltoid (sub-triangular) but rounded at the angles (Ikins, 1940). Location: Away from center.
PERISTOME (MOUTH): Size: Quite large; over one-half the diameter of the shell (Ikins, 1940). Shape: Decagonal (Ikins, 1940). Lip: Ambulacral and interambulacral lips practically equal; branchial incisions well developed (Ikins, 1940).
SPINES: Unknown.
SPECIMENS STUDIED & CONDITION: One specimen from the Collection of Ed Elliott (Coryell County). Holotype UT 40537 (Williamson County).
ETYMOLOGY
Named for the town of Leander, Williamson County, Texas, near the type locality (Ikins, 1940).
REMARKS & COMPARISONS
Remarks: Ikins (1940) noted this species has likely been misidentified as Salenia mexicana in the past. The Book Author suggests the granulation between pore pair sets separates this species from Leptosalenia.
Comparisons:
QUALITY CONTROL NOTES
Plate: SaLe-10
Series: Lower Cretaceous Group: Trinity Formation: Glen Rose
Locale: Copperas Cove County: Coryell Stage: Albian
Length: 11.8 mm Height: 8.5 mm
Specimen in photos: Collection of Ed Elliott
Repository: Private Collection
HOLOTYPE INFO:
Holotype: UT 40537 (BEG 40537) (Ikins, 1940).
Locality: Borrow pit on west side of road, 1 mile north of Leander, Williamson County, Texas (Ikins, 1940).
Stratigraphy: Upper clays of Walnut Formation, Fredericksburg Group.
SYNONYMY
- Salenia leanderensis Ikins, 1940
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: SALENIA Gray, 1835
Species: Salenia leanderensis Ikins, 1940
TYPE SPECIES: Cidaris scutigera Gray, 1835
DIAGNOSIS
Test circular and small (9 mm holotype). Ambulacra straight with two rows of about 12 imperforate, crenulate tubercles. Interambulacra composed of two rows of five plates. Apical disk circular and raised. Distinguished from S. mexicana by fewer ambulacral tubercles (12 vs 18–20) and fewer interambulacral plates (5 vs 6) (Ikins, 1940).
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Fredericksburg (Type); Trinity (Specimen).
Formations: Walnut Formation; Glen Rose Formation.
Stratigraphic Units: Lower Cretaceous, Albian.
Counties: Williamson (Type), Coryell.
Abundance: Rare.
DESCRIPTION
TOP: Length, width, height: 11.8 mm L × 8.5 mm H. Top shape: Subpentagonal (Book Author); circular in ambital outline (Ikins, 1940). Top domed: Abactinal surface gently and regularly rounded (Ikins, 1940). Prominent apical cap sits raised on the corona (Book Author).
SIDE: Ambitus: Positioned at midpoint between bottom and corona. Side shape: Slightly inflated (Ikins, 1940); sloping sides.
BOTTOM: Bottom shape: Adactinal surface practically flat (Ikins, 1940).
AMB: Amb shape: Quite straight and wide; widening only slightly between apical disk and peristome (Ikins, 1940). Book Author describes them as flexuous. Amb arrangement: About one-half the width of the interambulacra at the ambitus (Ikins, 1940). Two rows of tubercles are staggered between sets of pore pairs (Book Author).
PORE PAIRS: Arrangement: Unigeminal (Ikins, 1940); uniserial. Condition: Become irregular and crowded upon approaching the peristome (Ikins, 1940).
TUBERCLES: Primary Perforated: No (Imperforate). Primary Crenulate: Yes. Ambulacral Tubercles: Two alternating rows of about 12 tubercles (Ikins, 1940). Interambulacral Tubercles: Two rows of five plates; each plate ornamented with a scrobiculate boss bearing an imperforate, crenulate mamelon (Ikins, 1940). In studied specimen, two large and one smaller tubercle per row (Book Author).
GRANULES: Distribution: Ikins (1940) states "no granules between the tubercles" in the ambulacra. Book Author notes "granulation between sets of pore pairs." Interambulacral granules are arranged with one in the upper/lower adradial corners and five on the medial margin of each plate (Ikins, 1940).
FASCIOLE: Absent.
APICAL SYSTEM: Size: Large; diameter 6 mm in holotype (approx. 66%). Shape: Circular (Ikins, 1940) to pentagonal (Book Author). Raised above the surface. Plating: Oculars are triangular; genitals are perforated near the center. Ornamentation: Ikins (1940) noted "no ornamentation" on the type; Book Author notes genital plates have sutural pits at boundaries and midpoints.
PERIPROCT (ANUS): Shape: Slightly deltoid (sub-triangular) but rounded at the angles (Ikins, 1940). Location: Away from center.
PERISTOME (MOUTH): Size: Quite large; over one-half the diameter of the shell (Ikins, 1940). Shape: Decagonal (Ikins, 1940). Lip: Ambulacral and interambulacral lips practically equal; branchial incisions well developed (Ikins, 1940).
SPINES: Unknown.
SPECIMENS STUDIED & CONDITION: One specimen from the Collection of Ed Elliott (Coryell County). Holotype UT 40537 (Williamson County).
ETYMOLOGY
Named for the town of Leander, Williamson County, Texas, near the type locality (Ikins, 1940).
REMARKS & COMPARISONS
Remarks: Ikins (1940) noted this species has likely been misidentified as Salenia mexicana in the past. The Book Author suggests the granulation between pore pair sets separates this species from Leptosalenia.
Comparisons:
- Salenia mexicana: S. leanderensis is distinguished by size, fewer ambulacral tubercles (12 vs 18–20), and fewer interambulacral plates (5 vs 6) (Ikins, 1940).
- Hyposalenia phillipsae: S. leanderensis resembles S. phillipsae but has more ambulacral tubercles (12 vs 5), more interambulacral plates (5 vs 4), and a circular rather than pentagonal apical system (Ikins, 1940).
QUALITY CONTROL NOTES
- Stratigraphy Conflict: The Type Locality (Leander) is Walnut Formation (Fredericksburg). The studied specimen is Glen Rose Formation (Trinity). This suggests a longer stratigraphic range.
- Measurements: Holotype dimensions (9mm diam) are smaller than the studied specimen (11.8mm).
- Morphological Variation: Ikins described the apical system as having "no ornamentation," while the Book Author notes suture pits. This difference is frequently due to the preservation state (weathering) of the holotype versus fresh specimens.
