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Re: Longisquama's "feather-like" appendages in new study
Brad McFeeters <firstname.lastname@example.org> wrote:
> Does this study finally put to rest the hypothesis that the "appendages" are
> part of a plant?
This study seems pretty convinced that they are *not* plant material :
"The appendages’ imprints closely adjoin elements of bony
substance referable to the spines of thoracal vertebrae (gray
shaded in Fig. 3)."
"The first six appendages are
attached to the thorax with nos. 1–4 contacting the vertebral
column. Arguably they are adjacent to the spines of
subsequent thoracal vertebrae (but vertebral features are
difficult to discern (Fig. 3)."
The authors then go on to say, more explicitly:
"Why the appendages of Longisquama are not plant
The bizarreness of Longisquama’s appendages and their
remotely leaf-like morphology lead to the suggestion that
the appendage exemplars in the holotype may not be part of
the skeletal specimen, but that they represent a frond-like
plant organ, which became associated with the skeleton
through or after the death of the animal (Paul 2001, p. 64;
Fraser 2006, p. 130). We believe this is unlikely for several
1. The arrangement is regular; there is no sign that the
association was coincidental. Except for the caudalmost
impression, all elongate imprints set in along the
dorsal thorax, some are more strongly curved and
tapering close to the vertebral column. They do not
appear to continue below or above the skeleton.
2. Type of preservation: There is no indication of
carbonaceous preservation, otherwise occurring for
many plant fossils from the Longisquama type locality.
Moreover, plant organs preserved three-dimensionally,
with the impressions of the outer surfaces separated by
a core of fine-grained sediment, are not known from
macrofloral remains of the Madygen Formation.
3. We know of no plant organ which matches all the
principal characteristics of the appendages. Mesenteriophyllum
kotschnevii (Sixtel 1962), an endemic plant
fossil of unknown affinity, bears some similarity,
because it has a folded surface; it lacks the characteristic
curvature, hockey-stick-like outline, and asymmetric
partition, however. If their belonging to the
skeleton is questioned, a plausible alternative, explaining
what the elongate projections could be, would add
weight to these claims."