Loriolia kellumi (Thompson 2026)
Vernacular name: Flat Loriolia of the Lower Glen Rose
Plate: LoTe-10
Series: Lower Cretaceous Group: Trinity Formation: Lower Glen Rose (Unit 2)
Locale: Hancock County: Comal Stage: Albian
Length: 12.2 mm Height: 3.8 mm (H/D Ratio: 0.31)
Specimen in photo: NPL 83025 Status: HOLOTYPE
Collector: William R. Thompson, Jr.
Repository: Non-vertebrate Paleo. Lab., Univ. of Texas (NPL)
HOLOTYPE INFO
Holotype: NPL 83025. Designated herein as the name-bearing type for the flat Loriolia population of the Lower Glen Rose.
Locality: Hancock, Comal County, Texas.
Stratigraphy: Lower Glen Rose Limestone, Unit 2.
Note: This species represents the biological entity described as "depressed" and "equally flattened" on both poles by Clark (1893), Adkins (1928), and Whitney & Kellum (1966).
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: Emiratiidae (Ali, 1990)
Genus: LORIOLIA (Neumayr, 1881)
Species: Loriolia kellumi sp. nov.
TYPE SPECIES: Pseudodiadema bourgueti var. foucardi (Cotteau, 1851)
DIAGNOSIS
Test small, circular, and strikingly depressed (flattened) with parallel oral and aboral surfaces (Clark, 1893). Height-to-diameter ratio is consistently low (0.30–0.38). It is distinguished from Loriolia rosana (Smith & Rader, 2009) by:
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Trinity
Formation: Lower Glen Rose Limestone (specifically restricted to Unit 2).
Counties: Comal, Bandera, Kendall (Whitney & Kellum, 1966).
Abundance: Common within the restricted marls of the Lower Member.
DESCRIPTION
TOP (Aboral View):
Dimensions: 12.2 mm L × 3.8 mm H.
Top shape: Circular to weakly pentagonal (Clark, 1893).
Top domed: Not domed; "upper and lower surfaces about equally flattened" (Clark, 1893).
SIDE (Lateral View):
Ambitus: Positioned at mid-height (approx. 50% from bottom), creating a symmetrical profile.
Side shape: Rounded and inflated between the two flat poles (Clark, 1893).
BOTTOM (Oral View):
Bottom shape: Flat, slightly concave only at the immediate peristome edge (Clark, 1893).
AMBULACRA (AMB):
Amb shape: Narrow, lanceolate, and straight (Clark, 1893).
Amb arrangement: Two rows of primary tubercles, 11 or 12 in each row (Clark, 1893).
Amb width: Interambulacra are about twice the width of the ambulacra at the ambitus (Clark, 1893; Adkins, 1928). Contrast: L. rosana is 55-65% (Smith & Rader, 2009).
PORE PAIRS:
Arrangement: Uniserial on the flanks; lowest 6 to 9 pore-pairs are offset in triads to form short phyllodes near the peristome (Whitney & Kellum, 1966).
Shape: Round to slightly oval.
TUBERCLES:
Primary Perforated: Yes (Roemer, 1852).
Primary Crenulate: Yes (Roemer, 1852; Clark, 1893).
Ambulacral Tubercles: Decrease gradually and uniformly in size from the ambitus to the poles (Whitney & Kellum, 1966).
Interambulacral Tubercles: Two primary rows of 9 or 10 tubercles (Clark, 1893). Areolas are depressed and distinctly outlined (Clark, 1893).
Scrobicular Tubercles: Primary tubercles are surrounded by a ring of minute granules and secondary tubercles (Whitney & Kellum, 1966).
GRANULES:
Distribution: Test surface is densely covered in minute granules and secondary tubercles irregularly dispersed (Clark, 1893). Contrast: Lacks the organized "3 deep and 3 abreast" fields of L. rosana (Smith & Rader, 2009).
APICAL SYSTEM (DISCAL OPENING):
Size: Large; diameter approximately 50% of the test diameter (Clark, 1893).
Shape: Subcircular to pentagonal; may exhibit a slight posterior elongation (Whitney & Kellum, 1966).
Incision: Features a "deep incision in the right anterior ambulacrum" (Clark, 1893).
PERISTOME (MOUTH):
Size: Wide; covering nearly one-half the diameter of the test (Clark, 1893).
Shape: Round and depressed.
Lip: Ten incisions produce well-defined lobes at regular intervals (Clark, 1893).
ETYMOLOGY
Named kellumi in honor of Lewis B. Kellum (1897–1992), former Director of the Museum of Paleontology at the University of Michigan, who edited and posthumously published the F. L. Whitney manuscripts in 1966, providing the first clear morphological distinctions for the "flat" and "elevated" Glen Rose populations.
REMARKS & COMPARISONS
Remarks: Loriolia kellumi is established to resolve a persistent stratigraphic and taxonomic confusion. While Smith & Rader (2009) lumped all Glen Rose Loriolia under the name L. rosana, their description primarily fits the Upper Member forms which exhibit organized granulation and variable elevation. The Unit 2 population (Lower Glen Rose) remains morphologically distinct and consistently flat.
Comparisons:
Vernacular name: Flat Loriolia of the Lower Glen Rose
Plate: LoTe-10
Series: Lower Cretaceous Group: Trinity Formation: Lower Glen Rose (Unit 2)
Locale: Hancock County: Comal Stage: Albian
Length: 12.2 mm Height: 3.8 mm (H/D Ratio: 0.31)
Specimen in photo: NPL 83025 Status: HOLOTYPE
Collector: William R. Thompson, Jr.
Repository: Non-vertebrate Paleo. Lab., Univ. of Texas (NPL)
HOLOTYPE INFO
Holotype: NPL 83025. Designated herein as the name-bearing type for the flat Loriolia population of the Lower Glen Rose.
Locality: Hancock, Comal County, Texas.
Stratigraphy: Lower Glen Rose Limestone, Unit 2.
Note: This species represents the biological entity described as "depressed" and "equally flattened" on both poles by Clark (1893), Adkins (1928), and Whitney & Kellum (1966).
SYNONYMY
- Pseudodiadema texanum Clark, 1893, p. 55, pl. 18, fig. 1 (non Diadema texanum Roemer, 1852).
- Loriolia texana Adkins, 1928, p. 273, pl. 1, figs. 6, 7.
- Loriolia rosana Cooke, 1946 (In part: specifically referencing the depressed morphotypes).
- Pseudodiadema texanum Whitney & Kellum, 1966, p. 253, pl. 1, figs. 16–19 (nomen nudum).
- Loriolia rosana Smith & Rader, 2009 (In part: specimens attributed to the Lower Glen Rose).
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: Emiratiidae (Ali, 1990)
Genus: LORIOLIA (Neumayr, 1881)
Species: Loriolia kellumi sp. nov.
TYPE SPECIES: Pseudodiadema bourgueti var. foucardi (Cotteau, 1851)
DIAGNOSIS
Test small, circular, and strikingly depressed (flattened) with parallel oral and aboral surfaces (Clark, 1893). Height-to-diameter ratio is consistently low (0.30–0.38). It is distinguished from Loriolia rosana (Smith & Rader, 2009) by:
- Symmetrical profile: The ambitus is at mid-height, unlike L. rosana where it is below mid-height (Smith & Rader, 2009).
- Ambulacral Width: Narrower ambulacra (~50% of IA width) compared to the wider ambulacra (55–65%) of L. rosana (Smith & Rader, 2009).
- Granulation: Irregularly dispersed, minute granulation (Clark, 1893) that lacks the highly organized, dense fields described as "three deep and three abreast" in L. rosana (Smith & Rader, 2009).
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Trinity
Formation: Lower Glen Rose Limestone (specifically restricted to Unit 2).
Counties: Comal, Bandera, Kendall (Whitney & Kellum, 1966).
Abundance: Common within the restricted marls of the Lower Member.
DESCRIPTION
TOP (Aboral View):
Dimensions: 12.2 mm L × 3.8 mm H.
Top shape: Circular to weakly pentagonal (Clark, 1893).
Top domed: Not domed; "upper and lower surfaces about equally flattened" (Clark, 1893).
SIDE (Lateral View):
Ambitus: Positioned at mid-height (approx. 50% from bottom), creating a symmetrical profile.
Side shape: Rounded and inflated between the two flat poles (Clark, 1893).
BOTTOM (Oral View):
Bottom shape: Flat, slightly concave only at the immediate peristome edge (Clark, 1893).
AMBULACRA (AMB):
Amb shape: Narrow, lanceolate, and straight (Clark, 1893).
Amb arrangement: Two rows of primary tubercles, 11 or 12 in each row (Clark, 1893).
Amb width: Interambulacra are about twice the width of the ambulacra at the ambitus (Clark, 1893; Adkins, 1928). Contrast: L. rosana is 55-65% (Smith & Rader, 2009).
PORE PAIRS:
Arrangement: Uniserial on the flanks; lowest 6 to 9 pore-pairs are offset in triads to form short phyllodes near the peristome (Whitney & Kellum, 1966).
Shape: Round to slightly oval.
TUBERCLES:
Primary Perforated: Yes (Roemer, 1852).
Primary Crenulate: Yes (Roemer, 1852; Clark, 1893).
Ambulacral Tubercles: Decrease gradually and uniformly in size from the ambitus to the poles (Whitney & Kellum, 1966).
Interambulacral Tubercles: Two primary rows of 9 or 10 tubercles (Clark, 1893). Areolas are depressed and distinctly outlined (Clark, 1893).
Scrobicular Tubercles: Primary tubercles are surrounded by a ring of minute granules and secondary tubercles (Whitney & Kellum, 1966).
GRANULES:
Distribution: Test surface is densely covered in minute granules and secondary tubercles irregularly dispersed (Clark, 1893). Contrast: Lacks the organized "3 deep and 3 abreast" fields of L. rosana (Smith & Rader, 2009).
APICAL SYSTEM (DISCAL OPENING):
Size: Large; diameter approximately 50% of the test diameter (Clark, 1893).
Shape: Subcircular to pentagonal; may exhibit a slight posterior elongation (Whitney & Kellum, 1966).
Incision: Features a "deep incision in the right anterior ambulacrum" (Clark, 1893).
PERISTOME (MOUTH):
Size: Wide; covering nearly one-half the diameter of the test (Clark, 1893).
Shape: Round and depressed.
Lip: Ten incisions produce well-defined lobes at regular intervals (Clark, 1893).
ETYMOLOGY
Named kellumi in honor of Lewis B. Kellum (1897–1992), former Director of the Museum of Paleontology at the University of Michigan, who edited and posthumously published the F. L. Whitney manuscripts in 1966, providing the first clear morphological distinctions for the "flat" and "elevated" Glen Rose populations.
REMARKS & COMPARISONS
Remarks: Loriolia kellumi is established to resolve a persistent stratigraphic and taxonomic confusion. While Smith & Rader (2009) lumped all Glen Rose Loriolia under the name L. rosana, their description primarily fits the Upper Member forms which exhibit organized granulation and variable elevation. The Unit 2 population (Lower Glen Rose) remains morphologically distinct and consistently flat.
Comparisons:
- Vs. Loriolia rosana (Smith & Rader, 2009): L. kellumi is symmetrically flat (H/D ~0.31) with an ambitus at mid-height; L. rosana is asymmetrically elevated and variable (H/D 0.45–0.60) with an ambitus below mid-height (Smith & Rader, 2009). L. kellumi possesses irregular, minute granulation (Clark, 1893), whereas L. rosana has highly organized "fields" of secondary tubercles (Smith & Rader, 2009).
- Vs. Phymosoma texanum (Roemer, 1852): L. kellumi has perforate tubercles and uniserial pore pairs (except at the peristome); P. texanum has non-perforate tubercles and biserial pores at the apex (Roemer, 1852).
- Vs. L. whitneyi (Ikins, 1940): L. whitneyi occurs in the Walnut Formation and is distinguished by a more pronounced aboral depression in the interambulacra (Whitney & Kellum, 1966).
