Palaeos:		Tetrapoda
The Vertebrates		Eucritta

Tetrapoda: Eucritta

SARCOPTERYGII
|
TETRAPODA
|--Acanthostega
`--+--Ichthyostega
   `--+--Crassigyrinus
      `--+--Colosteidae
         |  `--Greererpeton
         `--+--Baphetidae
            |  |--Loxomma   
            |  `--+--Baphetes  
            |     `--Megalocephalus
            |--Eucritta
            `--Tetrapoda*
               |--TEMNOSPONDYLI
               `--+--LEPOSPONDYLI
                  `--REPTILIOMORPHA

1. Eucritta X

Eucritta melanolimnetes

Descriptions

Eucritta:  E. melanolimnetes Clack 1998

Range: Early Carboniferous (Brigantian, latest Viséan) of Europe (Britain). 

Phylogeny: Tetrapoda ::::: Tetrapoda* + Baphetidae + *.

Characters: $ snout short with nasals square or hexagonal; full compliment of dermal roofing bones [C98]; orbit anteroventrally embayed (perhaps only in larger individuals) [C01]; frontals long & narrow, without participation in orbit [C01]; prefrontal only weakly sutured to lacrimal & nasals [C01]; $ postorbital broadly crescentic without ventral process into orbit margin [C98]; $ skull table approximately square [C98]; parietals short, forming hexagonal plate [C01]; pineal foramen just posterior to orbits [C01]; postparietals relatively long [C01]; intertemporal present [C01]; $ supratemporal broadly crescentic [C98]; supratemporal contacts postparietal [C98]; supratemporal surrounds most of otic notch (not squamosal) [C98]; $ distance from apex of otic notch to orbit less than diameter of orbit [C98]; tabulars square, without button or horn (C01 notes that horn may have been lost) [C01]; paraquadrate foramen present [C01]; quadrate with broad dorsal plate and ventral articular surface [C01]; parasphenoid with broad triangular body thickened at edges in anterior portion [C98] [C01]; parasphenoid body with median smooth depression [C01];  parasphenoid with narrow cultriform process [C01]; basicranial articulation not fused [C98]; palate closed [C98]; broad vomerine plate [C98]; pterygoids meeting on midline [C98]; lower jaw of "standard" tetrapod pattern [C01]; coronoid-type crest & retroarticular process both absent [C01]; $ maxillary tooth count 38-40 with peak at positions 7-14 [C98]; fang pairs on vomers and palatines [C98]; palatines, vomers maybe all palatal bones, denticulated & striated [C01]; possible ectopterygoid tooth row [C01]; pterygoids and parasphenoid denticulated [C98]; cultriform process not denticulated [C01]; denticles and striations even on distal portion of quadrate ramus (!?) [C01]; pterygoids "striated" [C01]; dentary teeth unknown [C01]; axial skeleton poorly ossified circle [C98]; cervical ribs long, straight & somewhat expanded distally [C01]; trunk ribs only slightly curved & not expanded [C98] [C01]; single pair of stout sacral ribs [C01]; cleithrum present, long, straight, well-ossified, and expanded distally to wedge-shaped terminus [C98] [C01]; clavicles do not meet on mid-line [C01]; clavicle with dorsal blade having posterior face concave (cleithral articulation) [C01]; interclavicle diamond-shaped [C98]; interclavicle anterior edge crenellated (as some temnospondyls -- ATW) [C01]; scapulocoracoid single ossification, poorly ossified [C01] [C98]; humerus L-shaped [C98]; humerus entepicondyle quarter-circle [C98] [3]; humerus entepicondylar foramen present [C01]; ectepicondyle low [C01]; ulna more slender and slightly longer than radius [C01]; ulna with moderately developed olecranon process [C01]; manual unguals slender & tapered [C01]; ilium with both dorsal and posterior processes [C98]; femur ~ 18 mm (vs. 12-14 mm humerus) [C01]; tibia & fibula 11 mm, very similar, with interepipodial space [C01]; pes with five digits [C98]; pes phalangeal formula 2345? [C01]; ventral armor of narrow gastralia [C98]; dermal bone with pattern of radiating ridges [C01]. 

Notes: [1] as Clack (1998) notes, Eucritta is very close to basal temnospondyls in characters of the skull, except for the closed palate. [2] Clack (2001) makes the interesting point that the posterior stem on the interclavicle is a developmental artifact.  It gradually grows out into a full diamond-shape during ontogeny. [3] in Clack (2001) the entepicondyle is described as "triangular." From the figure in the later paper (at right), the "quarter-circle" may refer to the ectepicondyle.  

Comment: may be related to Temnospondyli

Links: AE TREE2000.pdf; relics: The creature from the black lagoon.  

References: Clack (1998) [C98], Clack (2001) [C01]. ATW020820.  

Images: Creature from the Black Lagoon (movie version) from The Uninhibited Uniform. Eucritta melanolimnetes life reconstruction by Dmitry Bogdanov MAK111112