Goniopygus whitneyi Smith and Rader, 2009
Plate: GoWh-10
Series: Lower Cretaceous Group: Trinity Formation: Glen rose
Locale: Canyon Lake County: Comal Stage: Albian
Length: 19.7 mm Height: 10.9 mm
Specimen in photo: NPL 83006 Hypotype
Collector: William R. Thompson, Jr.
University of Texas Non-vertebrate Paleo. Lab.
Plate: GoWh-20
Series: Lower Cretaceous Group: Trinity Formation: Glen Rose
Locale: Canyon Lake County: Comal Stage: Albian
Length: 8.2 mm Height: 4.1 mm
Specimen in photo: NPL 83007 Hypotype
Collector: William R. Thompson, Jr.
University of Texas Non-vertebrate Paleo. Lab. Juvenile.
Plate: GoWh-30
Series: Lower Cretaceous Group: Trinity Formation: Glen Rose
Locale: Canyon Lake County: Comal Stage: Albian
Length: 5.6 mm Height: 1.5 mm
Specimen in photo: NPL 83008 Hypotype
Collector: William R. Thompson, Jr.
University of Texas Non-vertebrate Paleo. Lab. Spine.
HOLOTYPE INFO:
Holotype: USNM 12320 — National Museum of Natural History, Smithsonian Institution (Clark & Twitchell, 1915)
Locality: Round Rock, Williamson County, Texas (Clark, 1893)
Stratigraphy: Edwards Limestone (Fredericksburg Group) (Clark, 1893)
SYNONYMY
Goniopygus guadalupae (Roemer, 1852)
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 zitteli Clark, 1891
TYPE SPECIES: Goniopygus major L. Agassiz, 1838
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Fredericksburg, Washita
Formations: Edwards Formation, Georgetown Formation
Stratigraphic Units: Lower Cretaceous, Albian
Counties: Williamson, Travis, Pecos, Borden
DESCRIPTION
TOP: Shape: Circular
SIDE: Ambitus: 30% from flat base
Side shape: Sub-globulose
BOTTOM: Flat base
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: 2.5 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: Imperforate
Primary Crenulate: Non-crenulate
Primary Boss: Scrobiculate
Coverage: Tubercles cover entire test, excluding apical system
APICAL SYSTEM: Size: Occupies 40% of top of test (Adult); 60% (Juvenile)
Shape: Flat, raised above corona
Type: Dicyclic
Plates: Plates without ornamentation. Oculars deltoid shaped. Genitals pointed, gonopores at each point. Juveniles have pits where oculars and genitals meet.
PERIPROCT (ANUS): Shape & Size: Oval (Adult); Lemon shaped (Juvenile)
Structure: Sits in triangular depression with a platform in 3 corners with a granule
PERISTOME (MOUTH): Size: Large; diameter 55% of base (Adult); 65% of base (Juvenile)
Lip: Ten notches with well-developed lips
SPINES: Shape: Paddle shaped, with two sides flatter. On paddle side is a depressed large cup-like indentation. Widest spot at 30% from end. Tip end bends downward and has a small dimple.
Structure: Base end has small acetabulum. Base and neck equally sized. Base end rounded, granules on end.
Ornamentation: Linear serrations run from collar, for entire shaft to rounded tip, excluding base.
Collar: Small.
SPECIMENS STUDIED & CONDITION
Specimen condition: Many juveniles and adult specimens studied. Measurements of 13.5 mm to 14.6 mm recorded for specimens sharing features of both.
ETYMOLOGY
Named in honor of Karl Alfred von Zittel (1839–1904), a prominent German paleontologist (Clark, 1891).
REMARKS & COMPARISONS
Remarks: Significant ontogenetic differences observed. Juveniles have a taller ambitus (45% from base), a trapezoidal shape from the side, a larger apical system (60% of top), and a larger peristome (65% of base) compared to adults . The "triangular depression" of the periproct is a key diagnostic feature for 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: GoWh-10
Series: Lower Cretaceous Group: Trinity Formation: Glen rose
Locale: Canyon Lake County: Comal Stage: Albian
Length: 19.7 mm Height: 10.9 mm
Specimen in photo: NPL 83006 Hypotype
Collector: William R. Thompson, Jr.
University of Texas Non-vertebrate Paleo. Lab.
Plate: GoWh-20
Series: Lower Cretaceous Group: Trinity Formation: Glen Rose
Locale: Canyon Lake County: Comal Stage: Albian
Length: 8.2 mm Height: 4.1 mm
Specimen in photo: NPL 83007 Hypotype
Collector: William R. Thompson, Jr.
University of Texas Non-vertebrate Paleo. Lab. Juvenile.
Plate: GoWh-30
Series: Lower Cretaceous Group: Trinity Formation: Glen Rose
Locale: Canyon Lake County: Comal Stage: Albian
Length: 5.6 mm Height: 1.5 mm
Specimen in photo: NPL 83008 Hypotype
Collector: William R. Thompson, Jr.
University of Texas Non-vertebrate Paleo. Lab. Spine.
HOLOTYPE INFO:
Holotype: USNM 12320 — National Museum of Natural History, Smithsonian Institution (Clark & Twitchell, 1915)
Locality: Round Rock, Williamson County, Texas (Clark, 1893)
Stratigraphy: Edwards Limestone (Fredericksburg Group) (Clark, 1893)
SYNONYMY
Goniopygus guadalupae (Roemer, 1852)
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 zitteli Clark, 1891
TYPE SPECIES: Goniopygus major L. Agassiz, 1838
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Fredericksburg, Washita
Formations: Edwards Formation, Georgetown Formation
Stratigraphic Units: Lower Cretaceous, Albian
Counties: Williamson, Travis, Pecos, Borden
DESCRIPTION
TOP: Shape: Circular
SIDE: Ambitus: 30% from flat base
Side shape: Sub-globulose
BOTTOM: Flat base
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: 2.5 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: Imperforate
Primary Crenulate: Non-crenulate
Primary Boss: Scrobiculate
Coverage: Tubercles cover entire test, excluding apical system
APICAL SYSTEM: Size: Occupies 40% of top of test (Adult); 60% (Juvenile)
Shape: Flat, raised above corona
Type: Dicyclic
Plates: Plates without ornamentation. Oculars deltoid shaped. Genitals pointed, gonopores at each point. Juveniles have pits where oculars and genitals meet.
PERIPROCT (ANUS): Shape & Size: Oval (Adult); Lemon shaped (Juvenile)
Structure: Sits in triangular depression with a platform in 3 corners with a granule
PERISTOME (MOUTH): Size: Large; diameter 55% of base (Adult); 65% of base (Juvenile)
Lip: Ten notches with well-developed lips
SPINES: Shape: Paddle shaped, with two sides flatter. On paddle side is a depressed large cup-like indentation. Widest spot at 30% from end. Tip end bends downward and has a small dimple.
Structure: Base end has small acetabulum. Base and neck equally sized. Base end rounded, granules on end.
Ornamentation: Linear serrations run from collar, for entire shaft to rounded tip, excluding base.
Collar: Small.
SPECIMENS STUDIED & CONDITION
Specimen condition: Many juveniles and adult specimens studied. Measurements of 13.5 mm to 14.6 mm recorded for specimens sharing features of both.
ETYMOLOGY
Named in honor of Karl Alfred von Zittel (1839–1904), a prominent German paleontologist (Clark, 1891).
REMARKS & COMPARISONS
Remarks: Significant ontogenetic differences observed. Juveniles have a taller ambitus (45% from base), a trapezoidal shape from the side, a larger apical system (60% of top), and a larger peristome (65% of base) compared to adults . The "triangular depression" of the periproct is a key diagnostic feature for 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.
