Archives of The Cold Blooded News

The Newsletter of the Colorado Herpetological Society

Volume 29, Number 11;   November, 2002

Scientific Collecting, Voucher Specimens, And Things Like That

by Dr. Sherman Minton

In 1892 Oliver P. Hay had no hesitation about listing the Mud Snake (Farancia abacura) and the Coral Snake (Micrurus fulvius) as part of the Indiana herpetofauna, but he was dubious about the presence of the Cottonmouth (Agkistrodon piscivorus) in the state. Today we know there are at least two spots in the state where the Cottonmouth almost certainly occurs. But probably no one alive today has seen a Mud Snake or a Coral Snake in the field in the Hoosier state. Voucher specimens collected about 1880 by the well-known naturalist, Robert Ridgeway and deposited in the National Museum of Natural History leave no doubt that the Mud Snakes once inhabited swamps of Knox County, Indiana. Moreover, he said one specimen was found with her eggs, making it clear this was a viable breeding population. He didn't get the last Mud Snakes in the state; they were reported again in 1894 by Angus Gaines, an amateur naturalist living at Vincennes. He didn't save any specimens, but Ridgeway's specimens give credence to his report. The Mud Snake seems to have vanished with the drainage of the extensive cypress swamps of southwestern Indiana, but there is the remote chance a small population may still exist. If it is found, do we take a voucher specimen? Probably not -- I'd settle for a good photograph.

The Cottonmouth, with much the same general range and habitat as the Mud Snake, eluded scientific discovery much longer. Of course in Oliver Hay's day and for years after, everyone who spent time outdoors knew there were poisonous water moccasins in all parts of Indiana. But no one could come up with a bona fide specimen until May of 1983 when Tony Wilson and I were asked to identify a large snake killed at Buffalo Bottoms near Jasper. It was a Cottonmouth, and we saw where it was taken. The original dead snake served as our voucher specimen. Subsequently, another Cottonmouth from a locality near the Ohio River on the Harrison-Crawford County border was found in the I.U. Southeast collection and documents another Indiana locality.

The Coral snake story is a puzzler. Some time about 1890, a colorful snake was killed near Milan in Ripley County and brought to Bigney's drug store in the nearby town of Sunman where it was preserved. It was identified by Professor A.J. Bigney and deposited in the collection of Moore's Hill College where he was on the faculty. He reported his find in the first number of the Proceedings of the Indiana Academy of Science and based this report, such herpetologists as Raymond Ditmars and Leonhard Stejneger considered the Coral Snake native to Indiana. After Moore's Hill College graduated its last class in 1919, its collections were transferred to Evansville College where Dr. Goethe Link relocated the specimen about 1950. He and I checked the measurements and ventral counts and found them close to those given by Bigney. We also determined it belonged to the western subspecies tener. The real puzzle is whether this snake was a remnant of a natural population or was accidentally introduced. No Coral snakes have been found near Milan or anywhere else in Indiana since then and this is far from the nearest authentic records in Arkansas and Mississippi. The country around Milan today does not look like the terrain where I have found coral snakes in this area. I believe that the Milan snake was one that had been accidentally brought up from the South and was living free until killed and identified -- in those days literally a one in a million chance.

My own story with the Indiana Scarlet Snakes is also strange. In the summer of 1935, four of us who regularly hunted snakes in the knobs near New Albany found an odd little snake we couldn't identify but which looked like the picture of the Scarlet Snake (Cemophora coccinea) in Ditmars' Reptile Book, the only reference book we had. Our husbandry techniques were extremely primitive in those days, and we put the little snake into a galvanized iron washtub with some other small snakes. A few days later, a heavy thunderstorm dumped several inches of water into the tub. The other snakes swam to freedom: the scarlet snake drowned. I preserved it, and a year or so later sent it to Dr. Ditmars who confirmed my identification. He didn't seem specifically surprised. This specimen might have been just as enigmatic as the coral snake record if Dr. Bernard Bechtel hadn't come to Indiana. In May of 1957, he, my eldest daughter, and I collected two scarlet snakes in the knobs in two days. None have been found in Indiana since. All the Indiana specimens were preserved and have been examined by others. I don't think we got the last ones. This is an uncommon snake throughout its range and extremely secretive. I'm pretty sure it still lives in the knobs. Because it looks so much like a small Red Milk Snake (Lampropeltis triangulum syspila), I'd not accept a record that wasn't backed up by an actual specimen or by a very good close-up photo of the head of ventral surface.

Voucher specimens don't have to document rarities to be scientifically useful. Dr. Douglas Rossman, now at Louisiana State University, was interested in the taxonomy of Ribbon Snakes, and particularly whether the eastern and western ribbon snakes, traditionally considered subspecies, might not actually be two full species. The crux of the matter was what happened where the ranges of the two forms came together. If they were subspecies, the characteristics separating them would gradually blend producing an intermediate or intergrade population. If they were species, both would maintain their identity. Indiana happened to be in the zone of greatest overlap, and, luckily for Doug, there were quite a few museum specimens from the state. He was able to demonstrate that they behave here and elsewhere as full species. Contrariwise, the small sample of Indiana and Kentucky Crowned Snakes (Tantilla coronata) provided evidence that the Appalachian population of this snake, once known as T.c. mitrifer, is not sufficiently different from lowland populations to be worthy of recognition.

An obvious alternative to preserved voucher specimens is photographs. But this has its problems. Few museums today are prepared and equipped to curate collections of 35 mm slides or other photographs. These usually remain with the photographer where they are more likely to be lost or damaged and often are difficult to obtain for examination. Not all herpetologists are good photographers, and even expert photographers have trouble occasionally with cameras and film. Some species are easily identified even in bad photos; the Alligator Snapper is a good example. For many species, however, the photographer must not only have a good camera but must also know exactly which features he wants to show -- the belly pattern of Graham's Queen Snake {Regina grahami), the head markings of False Map Turtles (Graptemys pseudo-geographica), the mental shields of the Coal Skink (Eumeces anthracinus). And many structures important in herpetological taxonomy -- teeth, hemipenes, femoral pores -- just can't be adequately seen in ordinary photos. Finally, I believe that honest and dishonest mistakes are more easily made with photos than with actual specimens.

The science of systematics is becoming ever more complicated. Two common Indiana tree frogs, (Hyla versicolor) and (H. chrysoscelis), are best identified by their calls; identification of salamanders in Ambystoma jeffersoniaum complex often requires measuring red blood cells; and minute differences in tooth shape seem to be all that separates the pond-breeding Ambystoma texanum from the recently described stream-breeding A. barbouri. When I had my formal training in herpetology, emphasis was on the statistical differences between populations and the "long series" -- a lot of specimens form one locality. The first money I ever made as a herpetologist was by collecting about 40 Chorus frogs (Pseudacris triseriata) from the type locality near New Harmony for a famous museum. The bright young herpetologist of today think of immunological distances, allo-enzymes, and DNA sequences. This still requires the collecting of animals from the wild. The need for many specimens from a locality isn't emphasized so much, but it is necessary to have both sexes and examples of more than one age group represented. Very rarely will this harm natural populations of a species. Sometimes it may help, for knowing the geographic variation, natural distribution pattern, and ecological requirements of an uncommon species often permits development of better measures for its protection. Because Donald Tinkle and Roger Conant determined that the Brazos Watersnake (Nerodia h. harteri) and Concho Watersnake (N.h. paucimaculata) differ from each other and from other water snakes, there has been an extraordinary effort to protect the habitat of these snakes.