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Abraham MirandaCSUSB3.5.09
Barrel bodiedSmall headsOriginally lumped together, the subclass
Edaphosauria includeEdaphosauridaeCaseaLupeosauridaeNitrosauridae
Romer appeared to have decided Edaphosaurus should have their own subclass, but he was overruled
Romer compared the Edaphosaurus to Casea because of their pelycosaur similarities
Projection off the frontal bone, creating a large lappet
Quadratojugal not connected to the subtemporal bar
Lacrimal bone reaches from the orbits to the naris
A narrow skull tableHave a supraorbial
brow or shelf created from the prefrontal, frontal and post frontal bones
Postorbital process reduced
No connection with the postorbital bone and supratemporal bone
Temporal bar is created from the jugal and squamosal bones
Quadratojugal jugal is reduced
Supraoccipital is smaller compared to sphenacodonts
Articulation of the jaw joint is below the rows of teeth
Dentary bone has a big coronid process
The prearticular bone is rotated to fit under the pterygoid process of articular bone
All marginal teeth slightly enlarged at distal portions
Sail: Formed by the neuro spinous processes of the cervical, thoracic, and lumbar vertebrae
Neural spines are circular at distal endsNeural spines are laterally compressed at
proximal ends Cervical neural spines bend anteriolyPosterior neural spines bend posteriorlyNeural spine tubercles paired at the proximal
ends
Neural spines enlongated on presacral bonesShort transverse tubercles
Distal neural spines loose dual cylinder structureStolen from Adam Huttenlocker
Limbs are shortAll Edaphosaurs have a curve to ribsTubercular head of ribs are small ridged
KANSAS
Oldest and most primitive of the EdaphosauridaeTwo well-preserved specimens found in Garnett, KansasFirst found in the Upper Pennsylvanian Rock Lake Shale
of the Stanton formation.A stream valley in which there was a slow transgression
of flood waters.First unearthed by P.E. Peabody in 1957, and thought to
be a Dimetrodon, Reisz in 1982 confirmed this unknown specimen as an edaphosaur
Maintained edaphosaur spines, but did not really fit in with the rest of the genus, so a new genus was erected: Ianthasaurus
Only known species of Ianthasaurus: Ianthasaurus hardestii
Insectivore
Pre and Postfrontal bones articulate to the Parietal
Reduced quadratojugal from the temporal bar
Small temporal fenestra
Long and low maxilla
27-29 teethEnlongate maxillaCaniniform teethSharp and recurved
posteriorly dentitionHomodont dentitionNo toothplates Palatine teeth infer
insectivory
Centrum lengths of the Cervical vertebrae are greated than the rest of the presacral vertebrae
Neural spines running of the cervical vertebrae are thicker and more robust
Transverse processes of the vertebrae are short
Ribs are not strongly curved like the rest of the edaphosaurs
Longest neural spine is at vertebrae 17
29 Presacral vertebrae
Lack tubercles on the neural spines
Neural spine sail is the smallest of the Edaphosauridae
No more than 5 tubercles on neural spines
27 Neural spines in the sail No central elements in all neural spines Neural spines lean forward in cervical
region and rearward in the lumbar region
Neural spines begin at third cervical vertebrae on down to the second to last lumbar vertebrae
Measurements of the centra impossible to crush and bad preparation
Proximal portions of the neural spines are laterally compressed
Neural spines are subcircular at the basal tubercle
Considered a tool for heat exchange over a sexual dimorphism or “solar collector”
Right scapulocorocoid
Left pelvisPartial manus Left humerous Only 2 usable
Ianthasaurus have been recovered
Medial view: the scapular and anterior corocoid is exposed.
Posterior corocoid is unavalible Scapula and corocoid are
separated by nature or by degradation along suture contact
Gleniod is too poorly preserved Supragleniod foramen exist? At the anterior margin of
scapular blade, a notch is seen in many pelcosaurs
Function? Anterior corocoid expanded
dorsoventrally and with a convex shape.
Function?
Humerus badly preserved and featureless
Distal end of humerous is narrow and no supinator process seen
Diaphysis is almost perfectly round in cross section
No evidence of the epiphyses being twisted about the bone
Identified as the ulnare, intermedium medial and lateral centrale
Nothing can be offered, not enough.
Illuim is well-developed with a blade-like processes extending posteriorly
The anterodorsal process is smaller than the posteriordorsal process
Ribs are slighly curved with a smooth tubercular bump
Complete ilium has been found Pubis and ischium have been
lost Iliac blade is extended
posteriorly like other primitive pelycosaurs
Obturator foramen on posterior edge , but posterior boarder is opened
Indicates that this specimen is immature
Ischium retains the structure of other early pelycosaurs
Pubis and ischium are narrowly connected below the acetabulum
Lived in the Lower Permian of North-Central Texas
Represented by a single skullShares 5 synapomorphies with Edaphosaurs
What is G?G= 5 reasons
Transverse flange of pterygiod is missing
The prefrontal bone ventral process is transversly expanded
No caniniform teethNo caniniform regionPremaxillary and maxillary teeth identical
8 species currently recognized
EdaphosaurusE. boanergesE. cruciger- largest
sailE. pogoniasE. novomexicanusE. colohistionE. credneriE. raymondi
Most species are described by 1 or 2 badly preserved skulls
Many specimens found in the Geraldine Bonebed in Archer County, Texas
Larger barrel shaped body over Ianthasaurus
Dozens of specimens found in North-Central Texas
Many complete skulls
No so many complete skeletons
Used as the model for all Edaphosaurs
Reduced skull sizeHead is the size of 5
dorsal centraNot as enlongate as the
IanthasaurusProcess of the postorbital
is short, not extending to the parietal foramen
Nasal bone is ¾ the size of the frontal
Subtemporal bar is displaced superiorly
Temporal fenestra is enlarged anteriorly and posteriorly
Supraorbital shelf is wide and deep concealing the orbits
Lacrimal bone is thin at the maxillae and progressively thickens posteriorly suggesting it carries some kind of load and transfers it to the prefrontal
Prefrontal and lacrimal form a buttress attachment for reinforcement
The nasal bone has a “scarred shelf” and sutures that lock into the prefrontal bone as well as thicken around the orbit.
Suggests that carries load for feeding
Premaxilla is enlongated in cross section
Premaxilla has 5 teeth, but none have survived to determine dimensions
The maxilla accomodates
18-21 teeth No Caniniform teethNo Caniniform regionNo pterygiod flangeAll Homodont/isodonty
dentition
Jaw is suspended way below the upper tooth row
Well developed tooth plates on palate and mandible
Densely packet teethTooth plates form on the
palate and inner aspect of the mandible
Palatal plate consists of the pterygoid ectopterygiod, and palatine
Mandibular tooth plate is formed by the coroniod, posterior coroniod, and prearticular bones
Denticulated plate is formed by the ant coroniod, coroniod and prearticular bones
120-150 teeth per palatal bone plate
Maxilla bone is twisted out laterally
Dentary bone is twisted in medially
Purpose?
Massive tooth plate found on the mandible, bigger than on the maxilla/palate
Deeply cut through mandibular symphysis
Jaw articulation denoted propalinal or front to back movement of jaws
Maxillary teeth progressively angle backwards as you go to the dentary bone
Reduced homodont dentition
Isodonty in the marginal teeth cropped plant matter
Teeth are distally swollen
Fine serrated tips curving backwards
Palatal and mandibular tooth plates served as primary grinders of plant matter
Posterior maxillae and dentary teeth assisted with minor grinding
Supraoccipital has little lateral exposure
Tabular bones are thick towards the parietal, but they are thin and suture into paraocciptal bones
Postorbital is a slender sigmiodal bone.
.
Cervical vertebrae are extremely short compared to the dorsal and lumbar vertebrae
Ianthasaurus has longer centra on their cervical vertebrae
Contain neural spines that are enlongated with longitudinal ridges at the sides of the spines
Anterior to mid dorsal neural spines are tall and pointed. E. boanerges has the second longest neural spines
Neural spines are tall and pointed with a slight posterior angulations
Multiple lateral tubercules that are arranged laterally across the neural spines
Neural spine tips of sacral and caudal vertebrae are roughened or crenulated like a castle
They have longitudianal ridges that are rough Anterior view w/ R rib
Ventrally hypertropied clavicle
A heavy scapular blade
A reinforced or
Butressed supragleniod fossa
Increased coracoid processes
Anterior neural spines neural spines lean forward, lean posteriorly towards lumbar neural spines.
Dorsal ribs are strongly curved to the midlineTuberculae are well developed and slightly
roughened
Ilium: anterodorsal process are in equal size of the posterodorsal process.
First fragments recovered by P.E. Raymond in Pitcairn,Pennsylvania in 1908
Romer and Price wanted to keep this sample as E. mirabilis, but renamed it due to geopgraphic incompatibilies (1940)
Permian sample Only small spine fragment with some
tubercles found
12mm longOval in cross-sectionAnterior and
posterior sides cannot be dicerned
Little of lateral tubercle survives
Unknown mature sample
Declared a novum vanum
Early Permian pelycosaur found in the Wichita deposits of Texas
First thought by Romer or intermediate betweeen Edaphosaurus and Dimetrodon
Lack of cranial fossilsLack of Ianthasaurus-like shoulder girdle,
nothing to compare it to.
Only 3 survivedCentrum is 30mm longHave a mid ventral keelThe centra have a
diamond shape when cut transversly
This aspect is considered to be conserved through out the vertebral column
Anterior and posterior articular faces have “heavy lips”
Transverse processes are nearly identical to Edaphosaurus
Sacral vertebrae have been recovered , but the number is unknown
Considered robust and shorter, but the anterolateral aspect is dominated by the articulation to the ribs
• NO tubercles• Elevated transverse processes across the vertebral column• Zygapophyses are elevated•The centrum have a projecting keel
Lacked trabecular crossbars in neural spines
Mid-Dorsal Neural spine end missing
Neural spines have a forward tilt of 20 degrees at the base
Neural spines appear triangular at the base
8 spines have been recovered, considered to belong to the cervical vertebrae
Tall and narrow, no lateral depressions or modifications
Subcircular in cross-section
Mid Dorsal neural spines extend vertically , or almost perpendicular to level of the vertebral column
Posteriodorsal neuro spinous processes lean posterior of the animal
Maintain a similar orientation to that of Ianthasaurus
Expanded ventral aspect
Slightly bigger than the range of the edaphosaur clavicle
Anteromedial aspect is thick but the anterodorsal aspect is missing. Maybe some of clavicle is missing!
Dorsal edge of scapula preserved
Scapula blade could be larger and longer than any previous recorded pelycosaur!
Probably smooth surfaced
Contains a broad convex fossa on medial side for large subcorocoid muscle
Supragleniod contains lots of bone
Gleniod fossa is marginally preserved, hard to analyze
An enlarged sail seems to be primitive, with advanced organisms down regulating the sail size.
Conversion from omnivorous to plant eater with advancing species
Edaphosaurs and Ianthasaurs clearly vary Look for key features Caniniform vs non-caniniform Prefrontal transverse process Smooth or roughened neural spines
Glaucosaurs: an interesting intermediateLupeosaurs are tenative edaphosaurs, but their
vertebral and spinous process features confirm their standing as Edaphosaurs
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