Goniopygus saleniaformis Ikins 1940
Plate: GoSa-10
Series: Lower Cretaceous Group: Fredericksburg Formation: Edwards
Locale: Crawford County: McLellan Stage: Albian
Length: 12.5 mm Height: 7.2 mm
Specimen in photo: NPL 10928 Type
Repository: Non-vertebrate Paleo. Lab., Univ. of Texas
HOLOTYPE INFO:
Holotype: BEG 20544 — Non-vertebrate Paleontology Laboratory, University of Texas (Ikins, 1940)
Locality: 5 miles west of Crawford, McLennan County, Texas (Ikins, 1940)
SYSTEMATIC PALEONTOLOGY – TAXONOMY
Class: Echinoidea Leske, 1778
Subclass: Euechinoidea Bronn, 1860
Infraclass: Carinacea Kroh & Smith, 2010
Superorder: Echinacea Claus, 1876
Order: Arbacioida Gregory, 1900
Family: Acropeltidae Lambert, 1911
Genus: GONIOPYGUS L. Agassiz, 1838
Species: Goniopygus saleniaformis Ikins, 1940
TYPE SPECIES: Goniopygus major L. Agassiz, 1838
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Fredericksburg
Formations: Edwards Formation (Ikins, 1940)
Stratigraphic Units: Lower Cretaceous, Albian
Counties: Coryell ; McLennan (Ikins, 1940)
DESCRIPTION
TOP: Length, width, height: 16.4 mm L × 8.7 mm H
Top shape: Circular
Top domed: Inflated, but curvature is gently sloping
SIDE: Ambitus: 1/3rd from bottom
Side shape: Inflated
BOTTOM: Large
AMB: Amb shape: Straight
Amb width: Widest at ambitus
Amb primary tubercles: Two rows of ten tubercles
Amb granules: Granules zigzag between the two rows of tubercles
INTERAMB: Interamb width: 1.4 times size of ambulacra
Interamb primary tubercles: Two rows of eight tubercles on alternating plates; some quite large
Interamb granules: Granules partially surround each tubercle
PORE PAIRS: Shape: Obliquely round
Arrangement: Uniserial
TUBERCLES: Primary Perforated: No Imperforate
Primary Crenulate: No Non-crenulate
Primary Mamelon: Largely mamelated
APICAL SYSTEM: Size: Diameter about 40% of top
Shape: Subpentagonal; sits on corona
Type: Dicyclic
Plates: Oculars deltoid shape. Genitals petal shaped, pointing away from center .
PERIPROCT (ANUS): Shape & Size: Skewed oval
Ornamentation: 3 small tubercles in 3 of 4 corners
PERISTOME (MOUTH): Size: Very large; diameter about 60% of base
Shape: Circular
Lip: Ten notches evenly spaced around peristome. Where ambs reach peristome, they bulge out into peristome slightly; remain straight at interambs .
SPINES: Unknown
SPECIMENS STUDIED & CONDITION Hypotype NPL 83009 .
REMARKS & COMPARISONS
Remarks: Ikins (1940) originally described this species as having a "suranal plate," a feature typically absent in Goniopygus, which led to the specific name saleniaformis (resembling Salenia). Cooke (1946) considered both Goniopygus saleniaformis and Goniopygus texanus to be variants (probably immature individuals) of Goniopygus zitteli Clark. Both have fewer apical tubercles than typical G. zitteli.
Remarks: Vadet, A. & Nicolleau, P., 2020 in Revision des Goniopygidae is proposing a method to classify and group Goniopygus species based on a specific biometric character: the size of the secondary tubercles in the ambulacral zone at the ambitus (equator). They lump all the Texas Albian/Cenomanian as (Cyphopygus zitteli) and that all others: (G. whitneyi, G. quartus, G. zitteli, G. texanus, G. saleniaformis, G. goodlandensis) are just growth stages They all possess small secondary ambulacral tubercles, suggesting that spine morphology and secondary tubercle size are the true diagnostic features for separating these echinoids, rather than the minor differences in shape or pore arrangement often used by earlier authors (like Ikins or Whitney) to name new species.
Plate: GoSa-10
Series: Lower Cretaceous Group: Fredericksburg Formation: Edwards
Locale: Crawford County: McLellan Stage: Albian
Length: 12.5 mm Height: 7.2 mm
Specimen in photo: NPL 10928 Type
Repository: Non-vertebrate Paleo. Lab., Univ. of Texas
HOLOTYPE INFO:
Holotype: BEG 20544 — Non-vertebrate Paleontology Laboratory, University of Texas (Ikins, 1940)
Locality: 5 miles west of Crawford, McLennan County, Texas (Ikins, 1940)
SYSTEMATIC PALEONTOLOGY – TAXONOMY
Class: Echinoidea Leske, 1778
Subclass: Euechinoidea Bronn, 1860
Infraclass: Carinacea Kroh & Smith, 2010
Superorder: Echinacea Claus, 1876
Order: Arbacioida Gregory, 1900
Family: Acropeltidae Lambert, 1911
Genus: GONIOPYGUS L. Agassiz, 1838
Species: Goniopygus saleniaformis Ikins, 1940
TYPE SPECIES: Goniopygus major L. Agassiz, 1838
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Fredericksburg
Formations: Edwards Formation (Ikins, 1940)
Stratigraphic Units: Lower Cretaceous, Albian
Counties: Coryell ; McLennan (Ikins, 1940)
DESCRIPTION
TOP: Length, width, height: 16.4 mm L × 8.7 mm H
Top shape: Circular
Top domed: Inflated, but curvature is gently sloping
SIDE: Ambitus: 1/3rd from bottom
Side shape: Inflated
BOTTOM: Large
AMB: Amb shape: Straight
Amb width: Widest at ambitus
Amb primary tubercles: Two rows of ten tubercles
Amb granules: Granules zigzag between the two rows of tubercles
INTERAMB: Interamb width: 1.4 times size of ambulacra
Interamb primary tubercles: Two rows of eight tubercles on alternating plates; some quite large
Interamb granules: Granules partially surround each tubercle
PORE PAIRS: Shape: Obliquely round
Arrangement: Uniserial
TUBERCLES: Primary Perforated: No Imperforate
Primary Crenulate: No Non-crenulate
Primary Mamelon: Largely mamelated
APICAL SYSTEM: Size: Diameter about 40% of top
Shape: Subpentagonal; sits on corona
Type: Dicyclic
Plates: Oculars deltoid shape. Genitals petal shaped, pointing away from center .
PERIPROCT (ANUS): Shape & Size: Skewed oval
Ornamentation: 3 small tubercles in 3 of 4 corners
PERISTOME (MOUTH): Size: Very large; diameter about 60% of base
Shape: Circular
Lip: Ten notches evenly spaced around peristome. Where ambs reach peristome, they bulge out into peristome slightly; remain straight at interambs .
SPINES: Unknown
SPECIMENS STUDIED & CONDITION Hypotype NPL 83009 .
REMARKS & COMPARISONS
Remarks: Ikins (1940) originally described this species as having a "suranal plate," a feature typically absent in Goniopygus, which led to the specific name saleniaformis (resembling Salenia). Cooke (1946) considered both Goniopygus saleniaformis and Goniopygus texanus to be variants (probably immature individuals) of Goniopygus zitteli Clark. Both have fewer apical tubercles than typical G. zitteli.
Remarks: Vadet, A. & Nicolleau, P., 2020 in Revision des Goniopygidae is proposing a method to classify and group Goniopygus species based on a specific biometric character: the size of the secondary tubercles in the ambulacral zone at the ambitus (equator). They lump all the Texas Albian/Cenomanian as (Cyphopygus zitteli) and that all others: (G. whitneyi, G. quartus, G. zitteli, G. texanus, G. saleniaformis, G. goodlandensis) are just growth stages They all possess small secondary ambulacral tubercles, suggesting that spine morphology and secondary tubercle size are the true diagnostic features for separating these echinoids, rather than the minor differences in shape or pore arrangement often used by earlier authors (like Ikins or Whitney) to name new species.
