[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: Type material: does it have to look pretty?



In a message dated 97-11-28 23:10:52 EST, bettyc@captivation.com writes:

<< What designates "Type material" in the situation where more than one
animals'
 remains are found at the same location at the same time?>>

The original describer, generally. Or a subsequent reviser, if, for example,
the original describer didn't realize there was more than one individual
present in the type material. If the material is scattered around in a
particular locality, so that it is likely but not completely clear that there
is a single individual present, then a single element or a few elements in
close association might be designated the type specimen, and the remaining
material simply referred to the species.

<< If, say. a new species of Protoceratops was found somewheres in the Gobi
in the
 typical mass scattering of remains (say 6 or 7 individuals), what makes one
 skeleton more likely to become the "type" than any of the others?
Completeness
 alone?    Quality of preservation over completeness?>>

It's up to the describer, who, we would hope, designates the "best" available
specimen. Sometimes the best-preserved or most complete specimen is not the
one that happens to show off the diagnostic feature or features to their best
advantage, in which case the describer could well select the most diagnostic
specimen over the best-preserved or most complete specimen.

<< And if sexual dimorphism is obviously present, which gets to be type-the
boy or
 the girl?   Or do you get a lectotype (supposed) male and a lectotype
(supposed)
 female plus the original "type" specimen? >>

There's no sexual bias in type-specimen selection (even if we knew [among
dino fossils] which is male and which is female). However, one sex or the
other might show off the diagnostic features better, so an individual of that
sex might be chosen as holotype over an individual of the other sex.
"Lectotype" doesn't mean "an additional type specimen"; a lectotype is simply
a type specimen selected in a different work from the original description,
when the original author's designation of a type specimen is found to be
ambiguous. There's usually (almost always) just one type specimen per species
in vertebrate paleontology.

The sum total of the type specimen plus all referred material from the type
locality, regardless of sex, etc., constitutes the "hypodigm" of the species.
The hypodigm "fills in" as much as possible of the anatomy of the species,
which may not be available from the type specimen alone.