Schoenesmahl dyspepsia, AND C. LONGIPES

SCHOENESMAHL DYSPEPSIA AND C. LONGIPES

Clear predator–prey interactions are rarely preserved in the fossil record. In the case of S. dyspepsia and C. longipes , there can be little doubt about the relationship between the former as a prey item of the latter.

I suggest that the total length of S. dyspepsia was approximately 250 mm. This is noteworthy because the total length of C. longipes is approximately 890 mm ( Ostrom, 1978). Thus, S. dyspepsia is more than one-quarter the length of the predator which ate it. As described above (see Taphonomy), the lizard may have been bitten into two pieces. The front half of the lizard seems to have suffered more trauma and is less completely known than the back part. The hind limbs seem mostly intact and the tail is folded into the anterior part of the gastrointestinal tract.

The folded condition of the tail is significant. Specifically, it raises the question: how did the tail come to be folded into the gullet of this coelurosaur? Certainly, modern birds lack the morphological equipment to fold a lizard tail into their mouths. Predatory birds tear their prey into pieces they can swallow ( Yosef, 1996, 2004; Fargallo et al., 2003; Young, Brodie & Brodier, 2004) or swallow it whole and usually headfirst (e.g. Newton & Newton, 1859; Brooker & Ridpath, 1980; Sherbrooke, 1990; Fargallo et al., 2003). I posit that the coelurosaur used its manus to place into its mouth the lizard, and subsequently used its manual digits to fold the tail into its oropharynx.

Despite the presence of numerous predator–prey interactions captured in the fossil record (e.g. Chen et al., 1998; Evans et al., 2004; Dal Sasso & Maganuco, 2011), the S. dyspepsia – C. longipes interaction is unusual in producing a situation wherein both taxa can be diagnosed and each is a holotype.

EVOLUTION OF PREDATOR AVOIDANCE IN SOLNHOFEN SQUAMATES

The recent revelation that snakes appeared by the Early Jurassic significantly extends the unknown lineages for many squamate. The Solnhofen squamates form a paraphyletic assemblage with respect to other known squamates, but most are similar in possessing related to predator avoidance and, perhaps, with diurnality versus nocturnality.

Modern lizards with relatively elongate limbs are generally diurnal and cursorial and/or scansorial whereas species with limbs that are shorter compared to their PCL are typically crevice-dwelling and/or nocturnal (see data in Müller et al., 2011 and Pianka & Vitt, 2003) and possess relatively short limbs. Note that arboreal or semi-arboreal forms may have essentially any limb proportions (see Pianka & Vitt, 2003; Müller et al., 2011).

Perhaps the short limbed Solnhofen forms were mostly nocturnal or crepuscular. Because the emerging coelurosaurs may also have functioned well in low-light conditions ( Schmitz & Motani, 2011), the elongate limbs of Ba. macrodactylus and S. dyspepsia may represent a shift toward relying less upon nocturnal habits for defence and more on cursoriality.

relatively short limbs ( Fig. 30, 31). Most of these species are of similar size to one another, but P. bavarica ( Fig. 31A) is much smaller than the others. Elongate limbs independently evolved in Ba. macrodactylus and S. dyspepsia ( Fig. 29). Exactly what this means with regards to the evolution of predator avoidance and ecology of squamates within the Solnhofen system cannot be confidently reconstructed.

Apparently, S. dyspepsia and Ba. macrodactylus were somehow different from other Solnhofen forms. Ardeosaurus brevipes ( Fig. 30A, 31B) and ‘ Ardeosaurus ’ digitatellus ( Fig. 30C) were relatively large-headed as compared to PMU R.58 ( Fig. 30B), E. schroederi ( Fig. 30D) and P. bavarica ( Fig. 31A), but this may be related to prey choice ( Pianka & Vitt, 2003) rather than predator avoidance. The limb proportions may be