- also
suggests this
suborder to be the
ancestral trilobite stock:
early protaspid stages have not been found,
supposedly because these were not calcified...
- co-occurring
middle Furongian (late Cambrian)
shumardiid trilobites and the
protaspid morphology of shumardiids".
Geological Magazine. 155 (6): 1247–1262. Bibcode:2018GeoM...
- secondarily. The
absence in the
fossil record of the
earliest larval stage, the
protaspid,
suggests that it may have been uncalcified,
which would be a
second unique...
-
coexisted sympatrically with the
protopteraspidid Lamiaspis, and
fellow protaspid Pirumaspis in a shallow-water
marine environment. It is
named for tubercule-like...
- the
early larval stage called protaspid is not known, and it is
generally accepted that this is
because the
protaspid was not calcified. Lieberman, B...
-
hatching from
roughly spherical eggs
averaging ~0.2mm in diameter, the
small protaspid and
early meraspid stages supposedly lived between the
plankton in the...
- and in some
species the
pleural region is segmented.
Examples of the
protaspid growth stage are
known in a few species. If present, the eyes of Eodiscina...
-
Order Agnostida,
Order Redlichiida. 1997 Shergold, John H. (1991). "
Protaspid and
early meraspid growth stages of the
eodiscoid trilobite Pagetia ocellata...
- to the
trilobite genus Isotelus or a
related taxon, and
conclude that
protaspid larvae represent a
developmental trait unique to trilobites. A
study on...
