Zemes un vides zinātnes Earth and Environment Sciences - Latvijas ...

E. Lukševičs, I. Zupiņš. Sedimentology, fauna, and taphonomy of Pav āri
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Fig. 8. Articulated specimens of Bothriolepis ciecere (A-F) and Ventastega curonica (G). A,
anterior ventro-lateral bones with articulated proximal segments of pectoral fin LDM 81/716 in
ventral view. B, head shield LDM 81/545 in dorsal view. C, articulated anterior dorso-lateral,
anterior ventro-lateral, central dorsal 1 and partial central ventral 1 LDM 81/434 in right lateral
view. D-F, proximal segments of pectoral fin: D, LDM 81/724 in dorsal view; E-F, LDM 81/723
in ventral and dorsal view. G, skull composed of two specimens, skull roof LDM 81/775 and left
cheek LDM 81/776, supposedly from one individual; specimens were found in a distance of 45
cm. Scale bar: 10 mm.
Bothriolepis ciecere and Ventastega curonica. Judging from the size of the fossil
bones, no remains of juvenile individuals at all have been found at the Pavari
oryctocoenosis. Bones of small sized placoderms are disproportionately rare (Fig. 7 B).
Large bones which could have belonged to older individuals are also comparatively
rare as well. This is the case for Ventastega as well. Judging from the individual size
range of vertebrates from the Pavāri oryctocoenosis, the assemblage is represented by
young adult and fully adult individuals as well as a few elder individuals. There are two
possible explanations for such age specific distribution of individuals. First of all, it is
possible that younger individuals (or juveniles) dwelled elsewhere aside from the adult
individuals as it use to be the case in aquatic animals. Secondly, a slightly delayed
burial might have resulted in bones of smaller individuals getting selectively destroyed.
Skeletal disarticulation. At the Pavāri site vertebrate remains are usually
represented by fully disarticulated plates of placoderms, separate teeth or bones of
sarcopterygians and tetrapods, but articulated portions of placoderm head shields,
trunk and pectoral fin armour, complete lower jaws or portion of skulls of
sarcopterygians and tetrapod, have also been found (Fig. 8). Most of articulated
specimens belongs to placoderm Bothriolepis and tetrapod Ventastega. There are
at least twelve more or less complete head shields of Bothriolepis ciecere found
among 664 specimens and 85 individuals belonging to this species. All complete
head shields are preserved without pineal plate, orbital and jaw ossifications, since