3============== Edopidae
2==|
| 4============== Cochleosauridae
1====|
| 6============== Dendrerpeton
| |
5==| 8=========== Dissorophoidae
| |
7==| 11==== Eryopidae
| 10=|
| | 12==== Zatrachydidae
9==|
| 14==== Dvinosauria
13=|
| 16= Archegosauridae
15=|
17= Stereospondyli
Consensus phylogeny of temnospondyls, from Milner and Sequeira (1994, 1998), Yates and Warren (2000) and Steyer (2000).
The following apomorphies (sorted by node) can be placed on the tree:
- Temnospondyli Zittel, 1888: presence of palatal tusks (Fig. 1);
vertebrae of 'rachitomous' to 'stereospondylous' type; and ornamented
scapular elements.
Click on an image to view larger version & data in a new window
Figure 1. Temnospondyl skulls in palatal view. A, Dendrerpeton acadianum. B, the eryopid Eryops megacephalus. C, the dissorophoid Tersomius texensis. D, the archegosaurid Melosaurus vetustus. Redrawn from A, Holmes, Carroll and Reisz (1998); B, from Sawin (1941); C, from Carroll (1964); and D, from Konzhukova (1955). Abbreviations: Bc, braincase; Ec, ectopterygoid; M, maxilla; Pa, palatine; Pm, premaxilla; Pp, postparietal; Pt, pterygoid; Q, quadrate; Qj, quadratojugal; Sp, sphenoid; Sq, squamosal; T, tabular. Drawings copyright © 2000 Jean-Sébastien Steyer and Michel Laurin.
- Edopoidea Romer, 1945 (as Edopsoidea): marginally elongate premaxilla (Milner and Sequeira, 1998).
- Edopidae Romer, 1945 (as Edopsidae): marginal dentition with pseudocanine peaking with maxillary swellings above the peaks (Milner and Sequeira, 1998).
- Cochleosauridae Broili in Zittel, 1923: depressed areas with subdued sculpture between parallel sculpture ridges on the skull table; relatively elongate prechoanal region of the vomer; and ectopterygoid separating from the subtemporal fossa (Milner and Sequeira, 1998).
- Unamed taxon: relatively wide interpterygoid vacuities, with vomer entering its margin (Fig. 1); presence of an alary process of the premaxilla (Sequeira and Milner, 1993).
- Dendrerpeton Owen, 1853: jugal narrowing to a point, making a point
contact with the lacrimal (Fig. 2); a possible lanceolate expansion
on the anterior tip of the cultriform process (Milner, 1996).
Click on an image to view larger version & data in a new window
Figure 2. Temnospondyl skulls in lateral view. A, Dendrerpeton acadianum. B, the eryopid Eryops megacephalus. C, the dissorophoid Tersomius texensis. D, the archegosaurid Melosaurus vetustus. Redrawn from A, Holmes, Carroll and Reisz (1998); B, from Sawin (1941); C, from Carroll (1964); and D, from Konzhukova (1955). Abbreviations: Bc, braincase; F, frontal; J, jugal; L, lacrimal; M, maxilla; N, nasal; Pm, premaxilla; Po, postorbital; Pof, postfrontal; Prf, prefrontal; Q, quadrate; Qj, quadratojugal; S, stapes; Sq, squamosal; St, supratemporal; T, tabular. Drawings copyright © 2000 Jean-Sébastien Steyer and Michel Laurin.
- Unnamed taxon: loss of the entepicondylar foramen of the humerus (when preserved); presence of the posterior coronoid of the mandible (except in the dvinosaurian Trimerorhachis) (Yates and Warren, 2000).
- Dissorophoidea Bolt, 1969: exposure of the dorso-lateral margin of the palatine in the orbital margin; narial, prefrontal and supratympanic flanges; both large orbits and pineal foramen; and long and slender limb elements (when preserved) (Dilkes, 1990; Yates and Warren, 2000; Steyer, 2000).
- Unnamed taxon: contact of the lacrimal with orbit but not with external naris; pineal foramen situated along the posterior or mid-length of the interparietal suture (Steyer, 2000).
- Eryopoidea Cope, 1882 (as Eryopsoidea): relatively rounded choana (Steyer, 2000), and possibly, a vertical iliac blade (Yates and Warren, 2000).
- Eryopidae Cope, 1882 (as Eryopsidae): anteriorly rounded interpterygoid vacuities; and large external nares (Sequeira, 1996; Steyer, 2000).
- Zatrachydidae Williston, 1910: lateral bony protuberances of the quadratojugual; a large internasal fenestra (Schoch, 1997; Steyer, 2000).
- Limnarchia Yates and Warren, 2000: paraquadrate foramen on the occipital face of the quadratojugual; perforated anterior palatal fossa (Fig. 1D); ectopterygoid toothrow (Fig. 1D); pterygoid with a conical recess dorsal of the pterygoid-parasphenoid articulation; maxilla-vomer suture (Fig. 1D); loss of denticles on the vomers; discrete postglenoid area on the mandible; and relatively elongate interclavicle.
- Dvinosauria Yates & Warren, 2000: reduction of the otic notch to a shallow embayment; loss of the postero-lateral flange on palatine ramus of the pterygoid; and 28 or more presacral vertebrae.
- Stereospondylomorpha Yates and Warren, 2000: Jugal extends anterior to the orbits (Fig. 2D); prefrontal-jugual suture (Fig. 2D); maxilla-nasal suture (Fig. 2D); and arcadian groove on the postglenoid area of the mandible.
- Archegosauridae Meyer, 1857 : absence of a triangular process of the premaxilla projecting posteriorly, medial to the naris; and a rugose, medial, premaxillary tubercle between the anterior palatal fossae (Yates and Warren, 2000).
- Stereospondyli Frass, 1889: palatine ramus of the pterygoid posteriorly retracted (Fig. 1D); pterygoid with a flat, broad internal process articulating with most of the lateral edge of the parasphenoid plate (Fig. 1D); and ornamentation of the ventral surface of the pterygoid (Yates and Warren, 2000).
