Wednesday, July 10, 2013

Research as it happens II: MOR round-up

Clockwise from left to right: the first draft of the monograph with marginalia, laptop with manuscript in progress, premaxillary teeth and the first maxillary tooth from the new species, loupe, and digital calipers.
I’ve put in full days over two weeks in the collections of the Museum of the Rockies (MOR; Bozeman, MT). In this entry I’ll provide a summary of what I’ve accomplished, what loose threads remain, and a description of the challenges in writing a monograph on limited time. As in the first entry, this follows a question-and-answer format.

How does the MOR collection compare to others?
For this specific project – the description of a new taxon – the MOR collections are among the best of the best for several reasons:

(1) There are multiple specimens of the new species.
Multiple specimens means that individual variation can be distinguished from ontogenetically- and phylogenetically-informative variation. A taxon based on a single specimen inevitably leads to false positives regarding assessments of the significance of features. For example, relatively primitive features turn out to be typical of juveniles, or unique features turn out to be individual variation after the sample size increases.

(2) A growth series is represented.
Ontogeny is at the core of my research program, and a solid understanding of ontogenetic variation is central to hypotheses of diversity and phylogenetic characters. In the monograph, each paragraph includes a description of ontogenetic variation, where possible; this approach lends a description the proper depth with which to identify features that are truly diagnostic of a new species. It sometimes turns out that specific growth changes can also diagnose a species.

In circumstances where I work without a growth series, I feel utterly blind regarding the data I collect – I simply do not know what it means, and it is a disquieting experience. Thankfully at the MOR I do not have to worry that I am working in the dark.

(3) The skulls are in some cases articulated, whereas others are disarticulated.
Although a completely articulated skull is a marvelous spectacle in a museum gallery, to a paleontologist’s eye it is a lot of missing data. Why? All of the surfaces of contact between apposed bones cannot be seen, and such surfaces contain information regarding ontogeny, phylogeny, function, and size.

The growth series that I have been working on includes a nearly completely articulated skull that thankfully is separated into several large sections. In this condition the specimen is much more maneuverable than a single unit of bone, which lends itself to a more complete and accurate description. The growth series also includes a completely disarticulated skull and skeleton, which gives me access to every surface of each bone that are otherwise blocked from view in the articulated skull. Finally, the series includes isolated bones that also provide a complete view of every bone.

(4) The skulls have associated postcrania.
Although much of my published work has focused on the craniofacial skeleton, I also work extensively on the postcranium. Fortunately, several of the skulls I am working on have associated postcranial skeletons in varying states of completeness. This provides the description with an appropriate osteological scope, and permits the identification of the various types of variation. This provides a more complete data set for quantitative phylogenetic- and ontogenetic analyses.

(5) There are multiple specimens of multiple taxa.
The MOR has more than one species of tyrannosaurid in its collection against which I can check to see if the features that I am describing in the new species are in fact unique. On several occasions I have found that a feature that I thought was diagnostic is seen in other species, whereas I have been able to identify features that are novel to the new species. Without a collection of this comparative scope, I would be utterly ignorant of the significance of the features that I document regardless of having the growth series.

With each of these qualities considered, the MOR is toe-to-toe with the collections at the American Museum of Natural History (New York, NY), Canadian Museum of Nature (Aylmer, QC), and the Royal Tyrrell Museum of Palaeontology (Drumheller, AB), at least when tyrannosaurids are considered.

Is there a cost to such a fantastic state of affairs?
Unfortunately, there is a cost to everything; several excellent specimens of skulls and postcrania that constitute a growth series means a tremendous amount of time must go into the research project to recover the data. For instance, on this project I have been writing up at least three specimens for each bone, which triples the amount of work and time that is spent, in contrast to cases where only one specimen is available.

This research trip will provide a baseline that I can use to estimate the time of completion for similar descriptive projects. So far, two whole months have gone into this project and I predict that it will take between one and two weeks to finish the collections-based part of it, which is longer than I expected that component to take.

What sort of flexibility do you allow yourself?
Although I do arrive at a collection with a plan to follow, I have to stay flexible in case time does become available to expand sections or add new bones. For instance, although I had planned for the monograph to stay focused on the skull, my progress on the latest trip was brisk enough that I did expand it to include the postcranium of what will become the type (name-bearing and reference) specimen. I then limited the comparisons with other specimens to that set of bones. I will also sometimes move ahead to writing up other bones if the inertia of having worked on the same bone for two days gets the better of me.

What did you get done, really?
Upon arrival, the monograph was 426 pages long (double spaced), and on the last day I had increased it to 611 pages – 185 pages written over two weeks. In addition to that, I took approximately 1157 measurements over one-and-a-half days; this is an overestimate since not all specimens are complete, but I did check each set of landmarks on each side of every specimen where necessary. I added 45 pages of tables, and over the space of one day I took 824 photographs.

What challenges do you face?
I think that the most significant challenge on any research trip is intrinsic, not extrinsic. It may come as a surprise that such work could be grueling, but the initial excitement of writing up a new species based on excellent fossils does become displaced by the tasks required to produce a work that meets the standards of the field. A description is a serious task that requires close attention and an ability to focus on several objectives at once. These include writing the basic description of what I see, taking note of ontogenetic variation, accommodating what has been said previously in the literature, quantifying features, etc.

Although writing an osteological description is primarily a task of the mind, it is tiring. My best time of day is in the morning, even though I am not a morning person. I can usually work for two days with high energy before I hit the ‘brick wall’ in the early afternoon of the third day and the others that follow. I experience the brick wall as an overwhelming sensation of inertia regarding the task before me and I can no longer sit still and write. As a remedy, I pace around to rid myself of the nervous, distracting energy. The best way that I combat the brick wall is to take advice given to undergraduate students when they study for an exam – don’t take on the task for several hours straight, instead take a break for 10-15 minutes every hour.

What advice do you have for students who are starting their first descriptive work?
Approach the fossil in a hierarchy from general to specific for the entire skull and then for each bone. After writing the description for each part, take measurements, followed by photographs. The idea is to complete one section before moving to the next. I’ll give an example of this approach in the bone-by-bone Osteology posts. The key is to follow an organized sequence; however, depending on the project, and the amount of material and time available to me, I’ll delay taking measurements and photographs until the last two or three days.

How is this work funded?
Small-scale projects like this do not qualify for large grants, such as those offered by the National Science Foundation (NSF). However, my travel costs for my first two trips to the MOR have been defrayed by small travel grants from my institution, Carthage College. On the occasions where those funds are not made available, I have carried the cost out of my own pocket.

What’s left for this project?
In terms of the collections work, several tasks are ahead of me: (1) expansion of the description of the pterygoid, (2) denticle counts for the mesialmost maxillary teeth of the type specimen need to be obtained, (3) the comparative description of the postcranium requires completion, (4) photographs of the postcranial bones of referred specimens need to be measured and photographed, (5) the subcutaneous surface of the ornamental cranial bones needs to be described, (6) the distribution of lesions are presently undocumented, and (7) several observations need to be included, based on the marginal notes in the first draft of the manuscript. Nearly there!

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