Ozimek bone histology

From the Konietzko-Meier et al 2024 abstract
“The small diapsid reptile Ozimek volans is one of the most enigmatic representatives of the Late Triassic fauna of Krasiejow, Poland. Phylogenetically, Ozimek was identified as a
‘protorosaurian’ related to tanystropheids, but the extremely elongated limbs and presumed gliding abilities are unusual for this group. This raises the question of whether the lifestyle inferred for this taxon is reflected in its bone histology.”

A competing hypothesis suggested Ozimek was a hitchhiker on larger aquatic taxa, based on its long slender limbs and tiny girdles, which were not built for vigorous transportation (Fig 1) distinct from all other tetrapods neither I, nor others, can think of.

The authors likened sectioned limb bones
to those of small bats, “with their small diameter, compact structure, low vascularization, no remodelling, and a lack of pneumaticity,”

Bats are very muscular flyers with a large pectoral girdle.
By contrast, Ozimek lacks large muscle anchors both pectoral and pelvic (Fig 2).

Due to taxon exclusion
the authors nested Ozimek with protorosaurs and tanystropheids (Fig 2). In the LRT the former are archosauromorphs, not related to the latter which are lepidosauromorphs. Convergence is the problem here. The LRT resolved this problem by adding taxa back to the Early Carboniferous and beyond. In the LRT Ozimek nested only within protorosaurs.

The authors wrote,
“In terms of morphology, Dzik & Sulej (2016) noted that the skeleton of Ozimek
shows similarities to that of Sharovipteryx mirabilis (Sharov 1971; Gans et al. 1987; Unwin et al. 2000, Fig 1).”

Missing from this citation list are Tatarinov 1989,1994; Peters 2000, Senter 2003, who also studied Sharovipteryx firsthand.

Everyone wants these taxa to fly
or glide despite the fact that no other taxa fly or glide with long hindlimbs. Only Peters 2000 identified bipedal traits in Sharovipteryx, which are obviously not present in Ozimek with its spindly limbs and tiny girdles, practically useless for any sort of transportation – unless provided by others (Fig 1).

We looked at Ozimek earlier here, here, here, here and here. The last was a 2021 abstract on the topic of bone histology similar to bats. Sometimes it takes 3 years for studies to go from abstract to paper.

The authors conclude,
“skeletal growth marks indicate that Ozimek grew much more slowly than bats and presumably had a rather low metabolic rate.”

If you didn’t drop your keys under the lamp post,
don’t look for them under the lamp post.

Consider other possibilities.
Give Ozimek a niche where a low metabolic rate not requiring high energy running or gliding is present (Fig 1).

Ozmik volans
(Dzik and Sulej 2016; Late Triassic) was originally described as a larger sister to Sharovippteryx due to its extraoridnarily long and slender limbs and elongate neck. Here it nests with Prolacerta. The girdles are smaller than in a similar-sized Prolacerta indicating a great reduction in the size of the limb muscles. Was this a floating predator? It does not look able to walk well on such spidery limbs. Perhaps it rode the wide flat skull of the giant amphibian, Metoposaurus (Fig 1, look closely for it on the top of the skull).

References
Dzik J and Sulej T 2016. An early Late Triassic long-necked reptile with a bony pectoral shield and gracile appendages. Acta Palaeontologica Polonica 61 (4): 805–823.
Konietzko-Meier D, Teschner EM, Tanczuk A and Sander PM 2024. I believe I can fly. . . New implications for the mode of life and palaeoecology of the Late Triassic Ozimek volans based on its unique long bone histology. Palaentology 67(3): e12715.
Peters D 2000. A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106 (3): 293–336.
Senter P 2003. Taxon Sampling Artifacts and the Phylogenetic Position of Aves. PhD dissertation. Northern Illinois University, 1-279.
Sharov AG 1971. New flying reptiles from the Mesozoic of Kazakhstan and Kirghizia. – Transactions of the Paleontological Institute, Akademia Nauk, USSR, Moscow, 130: 104–113 [in Russian].
Tatarinov LP 1989. [The systematic position and way of life of the problematic Upper Triassic reptile Sharovipteryx mirabilis.] Paleo. Zh. 1989(2): 110-112. [in Russian].
Tatarinov LP 1994. Terestrial vertebrates from the Triassic of the USSR with comments on the morphology of some reptiles. In: Mazin J.-M. & Pinna G. (Eds.) Evolution, ecology and biogeography of the Triassic reptiles. Paleo. Lomb. New Ser. 2.
Unwin DM, Alifanov VR and Benton MJ 2003. Enigmatic small reptiles from the Middle-Late Triassic of Kyrgyzstan. In: Benton M.J., Shishkin M.A. & Unwin D.M. (Eds) The Age of Dinosaurs in Russia and Mongolia. Cambridge: Cambridge U. Press: 177-186.

wiki/Sharovipteryx
wiki/Ozimek_volans

Source: https://pterosaurheresies.wordpress.com/2024/07/01/ozimek-bone-histology/