Goniopygus quartus Thompson, 2016
Plate: GoQu-10
Series: Lower Cretaceous Group: Trinity Formation: Glen Rose
Locale: Canyon Lake County: Comal Stage: Albian
Length: 13.8 mm Width: 7.3 mm
Collection: William R. Thompson, Jr.
Repository: Non-vertebrate Paleo. Lab., Univ. of Texas
HOLOTYPE INFO:
Holotype: NPL 73950 — Non-vertebrate Paleontology Laboratory, University of Texas
Paratype: NPL 73951
Locality: Mystic Shores, Canyon Lake, Comal County, Texas
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 quartus Thompson, 2016
TYPE SPECIES: Goniopygus major L. Agassiz, 1838
DIAGNOSIS
A Goniopygus very similar to Goniopygus whitneyi with a round periproct with multiple (4 to 6) depressed platforms containing 4 granules instead of 3 .
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Trinity
Formations: Glen Rose Formation (Unit 3)
Stratigraphic Units: Lower Cretaceous, Albian
Counties: Comal County
Association: Found in occurrence with Goniopygus whitneyi, Loriolia rosana, Tetragramma tenerum, Coenholectypus planatus, and Plagiochasma texanum .
DESCRIPTION
TOP: Length, width, height: 13.8 mm L × 7.3 mm H
Top shape: Round from above
Flatness: Flat corona
SIDE: Ambitus: 30% from adoral surface
Side shape: Inflated; sub-globulose
BOTTOM: Bottom flat: Flat bottom
AMB: Amb shape: Lanceolate; come to point at apical system, widest at ambitus, narrows at peristome
Amb primary tubercles: Two rows of tubercles with large mamelons stagger between the two rows of pores
INTERAMB: Interamb width: 2 times larger than ambulacra
Interamb primary tubercles: Half as many as in ambs; larger than amb tubercles
Interamb granules: Granules on plates
PORE PAIRS: Shape: Round
Arrangement: Uniserial; become offset at peristome
TUBERCLES: Primary Perforated: Non-perforated
Primary Crenulate: Non-crenulate
Primary Boss: Scrobiculate
Coverage: Tubercles cover entire test, excluding apical system
APICAL SYSTEM: Size: 5.9 mm; occupies 41% of top of test
Shape: Flat, raised above corona
Type: Dicyclic
Plates: Plates without ornamentation. Oculars deltoid shaped. Genitals pointed with gonopores at each point .
PERIPROCT (ANUS): Shape & Size: Oval; 3.3 mm
Structure: In depression with multiple platforms (4 to 6) containing 4 granules
PERISTOME (MOUTH): Size: Large (7.9 mm); diameter 57% of base
Lip: Ten rounded notches with pronounced to faint lips
SPINES: Unknown
SPECIMENS STUDIED & CONDITION Eight specimens studied. Holotype NPL 73950 .
ETYMOLOGY
This species is named after the Latin word for "fourth" (quartus) .
REMARKS & COMPARISONS
Remarks: Goniopygus quartus is just slightly less globular than G. whitneyi.
Comparisons:
G. whitneyi: Has 3 platforms with 3 granules in the periproct zone, giving it a triangular look. G. quartus has between 4 to 6 platforms with 4 granules .
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: GoQu-10
Series: Lower Cretaceous Group: Trinity Formation: Glen Rose
Locale: Canyon Lake County: Comal Stage: Albian
Length: 13.8 mm Width: 7.3 mm
Collection: William R. Thompson, Jr.
Repository: Non-vertebrate Paleo. Lab., Univ. of Texas
HOLOTYPE INFO:
Holotype: NPL 73950 — Non-vertebrate Paleontology Laboratory, University of Texas
Paratype: NPL 73951
Locality: Mystic Shores, Canyon Lake, Comal County, Texas
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 quartus Thompson, 2016
TYPE SPECIES: Goniopygus major L. Agassiz, 1838
DIAGNOSIS
A Goniopygus very similar to Goniopygus whitneyi with a round periproct with multiple (4 to 6) depressed platforms containing 4 granules instead of 3 .
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Trinity
Formations: Glen Rose Formation (Unit 3)
Stratigraphic Units: Lower Cretaceous, Albian
Counties: Comal County
Association: Found in occurrence with Goniopygus whitneyi, Loriolia rosana, Tetragramma tenerum, Coenholectypus planatus, and Plagiochasma texanum .
DESCRIPTION
TOP: Length, width, height: 13.8 mm L × 7.3 mm H
Top shape: Round from above
Flatness: Flat corona
SIDE: Ambitus: 30% from adoral surface
Side shape: Inflated; sub-globulose
BOTTOM: Bottom flat: Flat bottom
AMB: Amb shape: Lanceolate; come to point at apical system, widest at ambitus, narrows at peristome
Amb primary tubercles: Two rows of tubercles with large mamelons stagger between the two rows of pores
INTERAMB: Interamb width: 2 times larger than ambulacra
Interamb primary tubercles: Half as many as in ambs; larger than amb tubercles
Interamb granules: Granules on plates
PORE PAIRS: Shape: Round
Arrangement: Uniserial; become offset at peristome
TUBERCLES: Primary Perforated: Non-perforated
Primary Crenulate: Non-crenulate
Primary Boss: Scrobiculate
Coverage: Tubercles cover entire test, excluding apical system
APICAL SYSTEM: Size: 5.9 mm; occupies 41% of top of test
Shape: Flat, raised above corona
Type: Dicyclic
Plates: Plates without ornamentation. Oculars deltoid shaped. Genitals pointed with gonopores at each point .
PERIPROCT (ANUS): Shape & Size: Oval; 3.3 mm
Structure: In depression with multiple platforms (4 to 6) containing 4 granules
PERISTOME (MOUTH): Size: Large (7.9 mm); diameter 57% of base
Lip: Ten rounded notches with pronounced to faint lips
SPINES: Unknown
SPECIMENS STUDIED & CONDITION Eight specimens studied. Holotype NPL 73950 .
ETYMOLOGY
This species is named after the Latin word for "fourth" (quartus) .
REMARKS & COMPARISONS
Remarks: Goniopygus quartus is just slightly less globular than G. whitneyi.
Comparisons:
G. whitneyi: Has 3 platforms with 3 granules in the periproct zone, giving it a triangular look. G. quartus has between 4 to 6 platforms with 4 granules .
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.
