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Re: USNM 4734 Allosaurus fragilis topotype

In a message dated 11/18/02 1:34:31 AM Pacific Standard Time, Aegyptiacus 

<< what are topotype, syntype, paralectotype >>

Topotype: A specimen from the same locality as a type specimen (that is, a 
holotype or lectotype specimen) and, by virtue of its similarity to the type 
specimen, considered to belong to the same species.

Paralectotype: A referred specimen singled out for some reason by its 
describer, often because it is part of an original syntype series. This term 
has no scientific significance any more.

Syntype series: A set of specimens considered to belong to a single species 
and all together serving as the collective type specimen. When an author 
doesn't designate a particular specimen from a set of specimens to be a 
holotype or lectotype specimen, the whole set of referred specimens in the 
description is taken to be the syntype series. Later authors may remove 
specimens from a syntype series or may designate a particular specimen in the 
syntype series to be the lectotype specimen. You can see the nomenclatural 
problems that a syntype series can create(!).

For example, the teeth on which the species Deinodon horridus was originally 
based constituted a syntype series for that species. Later, some of the teeth 
were removed from the Deinodon horridus syntype series and became a syntype 
series for Aublysodon mirandus, and some more of the teeth became a syntype 
series for Dryptosaurus kenabekides. Eventually one of the Aublysodon 
mirandus teeth was designated the lectotype of Aublysodon mirandus, which 
made the other teeth in the syntype series simply referred specimens.

In case you've forgotten, the type specimen of a species is the set of one or 
more specimens that explicitly bear the species name. If it is one specimen, 
it is either the holotype specimen (if and only if it is designated the type 
specimen in the original description) or the lectotype specimen (if it is 
designated the type specimen in a publication after the original 
description). Otherwise the type is more than a single specimen and forms a 
syntype series (but part and counterpart of a slab count as the same 
specimen, even though they may have different catalogue numbers in a museum).

There's also a neotype: A specimen designated as a type specimen when the 
original type specimen of a species is lost or officially (by ICZN opinion) 
declared unusable as a type specimen.