Palaeos Vertebrates 200.100 Anapsida: Basal Anapsids (original) (raw)

Pal�os: Unit 200: Anapsida
The Vertebrates 100: Basal Anapsids

Taxa on This Page

  1. Anapsida
  2. Bolosauridae X
  3. Millerettidae X
  4. Owenettidae X
  5. Procolophonia
  6. Procolophonidae X
  7. Procolophonoidea X

Descriptions

ScutosaurusAnapsida (= Parareptilia):

Range: from the Permian

Phylogeny: Reptilia : Eureptilia+ * : Milleretidae + (Bolosauridae+ Procolophonia).

Characters: Caniniform teeth absent; posterior emargination of skull; dorsal expansion of quadratojugal; expanded iliac blade. Classically, no posttemporal fenestra; but this could be derived from the diapsid condition.

Image: from F el ning 5 (Lecture notes of Prof. John Peel & Prof. Lars Holmer, Uppsala Universitet, Department of Earth Sciences). Scutosaurus is a well-known pareiasaur.

Links: Introduction to the Anapsids; Phylogeny & Classification of Amniotes; Parareptiles;Reptiles - Subclass Anapsida;Anapsida -- The Dinosauricon;ANAPSIDA; Basal Anapsida after Berman et al., 2000, Lee, 1993, 1996 and ...;Literature - Anapsida;F el ning 5;Nathis Fauna Reptilelen. ATW030912.

Millerett idae **:**Most primitive anapsid group?

Range: Late Permian of South Africa.

Phylogeny: Anapsida : (Bolosauridae+ Procolophonia) + *.

Characters: Simple, conical teeth; retention of tabular, large supratemporal and postparietals; some forms with lateral temporal fenestra, but independently derived; lower temporal bar incomplete; stapes relatively small(?), light; impedance-matching ear likely; squamosal and quadratojugal embayed to support tympanum like diapsids (?) but unlike Testudines, which use quadrate; lizard-like?

Links: Introduction to Millerettidae;Nathis Fauna Reptilelen(Dutch -- brief discussion); reptiles(basic data); Kardong K(summary of phylogenetic placement); PANGEA(Italian -- quick summary and picture). ATW030304.

Bolosauridae: Bolosaurus, Eudibamus.

Range: Late Permian.

Phylogeny: Anapsida :: Procolophonia+ *.

Characters: Palate without teeth; transverse flange of pterygoid in same plane as palate; dentary and surangular form tall coronoid process; proximal portion of dentary covered by anterior process of prearticular; bulbous, occluding teeth; temporal fenestra long and low, between jugal and squamosal dorsally and quadratojugal ventrally; herbivorous.

Links: Dinosaur News: Eudibamus -ZoomDinosaurs.com; Basal Anapsida after Berman et al., 2000, Lee, 1993, 1996 and Modesto 1999, 2000; Early Permian Bipedal Reptile article in Science 11-3-00; PALEONTOLOGIA Correndo veloci nel passato (Italian); Reisz Lab: Bromacker Locality.

References: Berman et al. (2000).

Image and Note: Eudibamus cursoris from the Upper Permian of Germany, is the earliest known biped. Berman et al. reconstruct _Eudibamus_as a cursorial form. The image (a) shows a possible alternate reconstruction as saltorial. Berman et al. reject an arborial clinging & jumping habit because the penultimate phalanges are not elongated as in other organisms with this locomotor style. However, no other cursor or jumper has the primitive tarsal structure of Eudibamus. Accordingly, it may not be entirely safe to rely on such comparisons. Eudibamus has the short neck of a jumping form, although the pelvis is so slight as to make either running or jumping questionable. 010416.

Nyctiphruretus acudens Procolophonia:(= Ankyramorpha sensu deBraga & Rieppel (1997)?). Seeley 1888: defined as LCA Pareiasaurs + Procolophonoids or Pareiasaurs + turtles.

Range: fr Middle(?) Permian.

Phylogeny: Anapsida :: Bolosauridae+ * : Procolophonoidea + (Testudines+ Hallucicrania).

Introduction: The Procolophonia are a group of early herbivorous reptiles that flourished during the Permian to Triassicperiods. Although belonging to the basal anapsid (Parareptilia) group, their earliest members were still specialised enough to make an understanding of their relationships difficult. It appears that they may have evolved from basic captorhinid stock. Their nearest relatives seem to be the millerosaurs, a group of small unspecialised Permian reptiles.

The Procolophonia appeared suddenly in the late Permian, when they were at their most diverse, with several lineages evolving side by side. From the ancestral Nyctiphruretids, the small Procolophonoids evolved and flourished during the Triassic. Only the Procolophnidae survived upto the end of the period. Turtles (Chelonia) may have evolved from late pareiasaus or late procolophonids, but this is not certain. The earliest known turtles date from the Norian, and no transitional forms are as yet known. (MAK).

Links: More Nyctiphruretus acudens; Phylogeny and Classification of Amniotes; Introduction to Procolophonoidea

Image: Nyctiphruretus acudens from Mathematics. 010213.

Procolophonoidea:

Range: P-T.

Phylogeny: Procolophonia : (Testudines+ Hallucicrania) + * : Owenettidae+ Procolophonidae.

Characters: Close to Testudines. Post enlargement of orbit, exposing jaw musculature; concave ventral edge of skull in postorbital area. Caudal ribs not fused to centra. 3 sacral ribs. T forms had many broad or peg-like teeth, probably herbivorous. Deep quadrate emargination (? Carrol says tympanum supported by squamosal) & slender stapes. Later forms have long processes from lower cheek � like Pareiasaurs?

Links: link;link; Triassic Skulls; PANJAEA - Bone fossils gallery.

Owenettidae:

Range: Permian of South Africa

Phylogeny: Procolophonoidea : Procolophonidae+ *.

Characters: large pineal foramen as in therapsids; small sharp teeth (probable insectivorous diet). 020412.

Procolophonidae:

Range: Triassic

Phylogeny: Procolophonoidea : Owenettidae+ *.

Introduction: The Procolophonidae are a group of early herbivorous reptiles of the anapsid lineage that attained a world-wide distribution during the Triassicperiod. They were small stocky creatures, with blunt chisel-like teeth and triangular skulls.

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