Echinopsis lineata (Clark & Twitchell, 1915)
Plate: EcLi-10
Series: Upper Cretaceous Group: Washita Formation: Grayson Marl
Locale: Denison County: Grayson Stage: Cenomanian
Length: 25.1 mm Height: 16.3 mm
Specimen in photo: USNM 31198 (Holotype)
Repository: National Museum of Natural History (NMNH), Smithsonian Institution
HOLOTYPE INFO:
Holotype: USNM 31198 — National Museum of Natural History, Smithsonian Institution (Clark & Twitchell, 1915)
Locality: Denison, Grayson County, Texas (Clark & Twitchell, 1915)
SYNONYMY
SYSTEMATIC PALEONTOLOGY – TAXONOMY
Class: Echinoidea Leske, 1778
Subclass: Euechinoidea Bronn, 1860
Infraclass: Carinacea Kroh & Smith, 2010
Superorder: Echinacea Claus, 1876
Order: Camarodonta Jackson, 1912 (or Temnopleuroida)
Family: Glyphocyphidae Duncan, 1889
Genus: ECHINOPSIS L. Agassiz, 1840
Species: Echinopsis lineatus (Clark & Twitchell, 1915)
TYPE SPECIES: Echinus elegans Desmarest, 1825
DIAGNOSIS
Test medium size, slightly polygonal in ambital outline, tumid above, subhemispherical, slightly concave below. Ambulacra with compound plates covered with two rows of primary tubercles perforate and crenulate. Interambulacra with six rows of primary tubercles, which rapidly decline in size above the ambitus. Peristome small (Clark & Twitchell, 1915).
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Washita (Clark & Twitchell, 1915)
Formations: Grayson Marl (Denison Formation) (Clark & Twitchell, 1915)
Stratigraphic Units: Upper Cretaceous, Cenomanian
Counties: Grayson County (Clark & Twitchell, 1915)
DESCRIPTION
TOP: Length, width, height: 25.1 mm L × 16.3 mm H
Top shape: Round ; Slightly polygonal in ambital outline (Clark & Twitchell, 1915)
Top domed: Tumid upper surface (Clark & Twitchell, 1915)
SIDE: Ambitus: 40% from adoral surface
Side shape: Globular; subhemispherical (Clark & Twitchell, 1915)
BOTTOM: Bottom shape: Slightly concave (Clark & Twitchell, 1915)
AMB: Amb shape: Narrow, lanceolate; pointed at apical system, only slightly narrows at peristome
Amb primary tubercles: Two vertical rows of about 25 primary tubercles; near peristome, tubercles large and rows near perpendicular
Amb arrangement: Compound plates with a low primary adorally (Clark & Twitchell, 1915)
Amb primary zones: Poriferous zones not sharply defined (Clark & Twitchell, 1915)
INTERAMB: Interamb width: Slightly less than 3 times size of ambulacra
Interamb primary tubercles: Six rows of primary tubercles running length of interambulacra. Largest at ambitus; rapidly decline in size above ambitus (Clark & Twitchell, 1915). Two outside rows near peristome get smaller and are near perpendicular to amb rows. Inner four rows form "V" shapes meeting at or before peristome .
PORE PAIRS: Arrangement: Uniserial throughout
TUBERCLES: Primary Perforated: Yes (Clark & Twitchell, 1915; Thompson, 2016)
Primary Crenulate: Yes (Clark & Twitchell, 1915; Thompson, 2016)
Secondary tubercles: Secondary row of smaller tubercles near ambitus only in ambs
Granules: Further granulation runs throughout ambs
APICAL SYSTEM: Condition: Missing ; Wanting (Clark & Twitchell, 1915)
PERIPROCT (ANUS): Unknown
PERISTOME (MOUTH): Size: Small (Clark & Twitchell, 1915); Diameter about 45% of diameter of test
Lip: Notches small but distinct; cut well into the interamb; arranged on either side of the middle row of interamb tubercles ; Slight branchial incisions (Clark & Twitchell, 1915)
SPECIMENS STUDIED & CONDITION: Holotype USNM 31198 .
ETYMOLOGY: From the Latin lineatus, meaning "lined," likely referring to the distinct vertical rows (lines) of tubercles or pore zones.
REMARKS & COMPARISONS
Remarks: This species looks very similar to Pedinopsis molineuxae, but Echinopsis lineatus is uniserial throughout, whereas P. molineuxae is biserial aborally and uniserial adorally .
Taxonomy: The genus name Echinopsis is feminine; strictly speaking, the species name should be lineata to agree in gender. Clark & Twitchell often used masculine endings for feminine genera.
Plate: EcLi-10
Series: Upper Cretaceous Group: Washita Formation: Grayson Marl
Locale: Denison County: Grayson Stage: Cenomanian
Length: 25.1 mm Height: 16.3 mm
Specimen in photo: USNM 31198 (Holotype)
Repository: National Museum of Natural History (NMNH), Smithsonian Institution
HOLOTYPE INFO:
Holotype: USNM 31198 — National Museum of Natural History, Smithsonian Institution (Clark & Twitchell, 1915)
Locality: Denison, Grayson County, Texas (Clark & Twitchell, 1915)
SYNONYMY
- Micropsis lineatus Clark & Twitchell, 1915
SYSTEMATIC PALEONTOLOGY – TAXONOMY
Class: Echinoidea Leske, 1778
Subclass: Euechinoidea Bronn, 1860
Infraclass: Carinacea Kroh & Smith, 2010
Superorder: Echinacea Claus, 1876
Order: Camarodonta Jackson, 1912 (or Temnopleuroida)
Family: Glyphocyphidae Duncan, 1889
Genus: ECHINOPSIS L. Agassiz, 1840
Species: Echinopsis lineatus (Clark & Twitchell, 1915)
TYPE SPECIES: Echinus elegans Desmarest, 1825
DIAGNOSIS
Test medium size, slightly polygonal in ambital outline, tumid above, subhemispherical, slightly concave below. Ambulacra with compound plates covered with two rows of primary tubercles perforate and crenulate. Interambulacra with six rows of primary tubercles, which rapidly decline in size above the ambitus. Peristome small (Clark & Twitchell, 1915).
STRATIGRAPHICAL OCCURRENCE & DISTRIBUTION
Group: Washita (Clark & Twitchell, 1915)
Formations: Grayson Marl (Denison Formation) (Clark & Twitchell, 1915)
Stratigraphic Units: Upper Cretaceous, Cenomanian
Counties: Grayson County (Clark & Twitchell, 1915)
DESCRIPTION
TOP: Length, width, height: 25.1 mm L × 16.3 mm H
Top shape: Round ; Slightly polygonal in ambital outline (Clark & Twitchell, 1915)
Top domed: Tumid upper surface (Clark & Twitchell, 1915)
SIDE: Ambitus: 40% from adoral surface
Side shape: Globular; subhemispherical (Clark & Twitchell, 1915)
BOTTOM: Bottom shape: Slightly concave (Clark & Twitchell, 1915)
AMB: Amb shape: Narrow, lanceolate; pointed at apical system, only slightly narrows at peristome
Amb primary tubercles: Two vertical rows of about 25 primary tubercles; near peristome, tubercles large and rows near perpendicular
Amb arrangement: Compound plates with a low primary adorally (Clark & Twitchell, 1915)
Amb primary zones: Poriferous zones not sharply defined (Clark & Twitchell, 1915)
INTERAMB: Interamb width: Slightly less than 3 times size of ambulacra
Interamb primary tubercles: Six rows of primary tubercles running length of interambulacra. Largest at ambitus; rapidly decline in size above ambitus (Clark & Twitchell, 1915). Two outside rows near peristome get smaller and are near perpendicular to amb rows. Inner four rows form "V" shapes meeting at or before peristome .
PORE PAIRS: Arrangement: Uniserial throughout
TUBERCLES: Primary Perforated: Yes (Clark & Twitchell, 1915; Thompson, 2016)
Primary Crenulate: Yes (Clark & Twitchell, 1915; Thompson, 2016)
Secondary tubercles: Secondary row of smaller tubercles near ambitus only in ambs
Granules: Further granulation runs throughout ambs
APICAL SYSTEM: Condition: Missing ; Wanting (Clark & Twitchell, 1915)
PERIPROCT (ANUS): Unknown
PERISTOME (MOUTH): Size: Small (Clark & Twitchell, 1915); Diameter about 45% of diameter of test
Lip: Notches small but distinct; cut well into the interamb; arranged on either side of the middle row of interamb tubercles ; Slight branchial incisions (Clark & Twitchell, 1915)
SPECIMENS STUDIED & CONDITION: Holotype USNM 31198 .
ETYMOLOGY: From the Latin lineatus, meaning "lined," likely referring to the distinct vertical rows (lines) of tubercles or pore zones.
REMARKS & COMPARISONS
Remarks: This species looks very similar to Pedinopsis molineuxae, but Echinopsis lineatus is uniserial throughout, whereas P. molineuxae is biserial aborally and uniserial adorally .
Taxonomy: The genus name Echinopsis is feminine; strictly speaking, the species name should be lineata to agree in gender. Clark & Twitchell often used masculine endings for feminine genera.
