Archives of The Cold Blooded News

The Newsletter of the Colorado Herpetological Society

Volume 31, Number 9;   September, 2004

Sceloporus jarrovii, Cope, 1875 - Yarrow's Spiny Lizard

by Edward O. Moll
Adjunct Professor, School of Renewable Natural Resources, University of Arizona

However on any bright, warm day throughout the year, visitors are likely to observe Yarrow's spiny lizards. These medium-sized lizards are arguably the most obvious herps in the preserve. Near the Visitor's Center (5,500'), there appears to be a changing of the guard as Clark's spiny lizard, a species of the lower mountain slopes, is replaced by Yarrow's, a less arboreal and more saxicolous species. Rocky expanses with abundant crevices are optimum habitat to look for the Yarrow's spiny. Such being the case, visitors wishing to see high densities of the lizard should follow the steep Hamburg trail up to the "overlook" (6250'), a particularly rocky site. Here one can sit on a boulder in the sun and observe a number of these heliotrophic saurians doing the same thing.

For the most part, Yarrow's spiny lizard appears to be a typical member of its genus, although the scales are somewhat less spiny and imbricate than those of many species. Males are typical "blue bellies," advertising their territories by bobbing and doing "pushups" to display their bright blue ventral patches. Their heads are dark dorsally with light striping laterally but may be almost completely black in some adult males. The neck sports a black collar bordered by a white posterior stripe. The dorsal scales are decked with pinkish to cream-colored spots that may become blue to blue green posteriorly and onto the tail. Like many others of their genus, they show a predilection for beetles and ants. They in turn are favored prey of such predators as the Sonoran mountain kingsnake and banded rock rattlesnake. Even the diminutive twin.spotted rattlers will take adult Yarrow's. William Woodin, in his extensive field work in the Huachucas, found a twin-spot (435 mm in total length), near the Hamburg Mine (7000') that had managed to swallow a large adult Yarrow's. The snake was having some difficulty in locomotion but otherwise appeared none the worse for its gluttony.

What makes Yarrow's a more successful high elevation species than its lower elevation cousins such as the Clarks? T. A. Burns studied this problem in the Graham Mountains for his PhD dissertation. He found no differences in hemoglobin content, percent hematocrit, erythrocyte size and numbers, or blood glucose levels that would answer the question. He did observe that through basking and metachrosis (darkening of the skin in response to low temperatures), Yarrow's were able to maintain preferred body temperatures of 32 to 33° C at elevations where air temperature does not exceed 30°. Perhaps the most major departure of Yarrow's spiny from other Arizona Sceloporus is that it is live-bearing rather than oviparous. This is adaptive to living at high elevations, as eggs laid at these altitudes develop very slowly. However, gravid females through behavioral thermoregulation maintain body temperatures several degrees higher than ambient temperatures, thus promoting more rapid development of the offspring. The young can be born earlier during more favorable periods of the year. Similarly, Short-horned lizards, another high elevation species, differ from lower elevation Phrynosoma by being live-bearing.

The taxonomic history of Yarrow's spiny lizard involves an intertwining of the lives of a quiet, unassuming physician naturalist, Henry Crecy Yarrow and the fiery-tempered Edward Drinker Cope, perhaps the most famous (or at least most infamous) herpetologist/paleontologist of the nineteenth century. Interestingly, Yarrow and Cope were both born in 1840 in Philadelphia. From this point these two biologists with conflicting personalities followed somewhat different paths that eventually converged on the Wheeler Survey of western U.S. beyond the 100th Meridian.

Yarrow received his M.D. from the University of Pennsylvania in 1861 after two years of study (there apparently wasn't a lot to learn in those days). He immediately joined the 5th Pennsylvania Cavalry as an Assistant Surgeon. From this point on Yarrow spent most of his career with the U.S. Army as a medical officer. It was during his army career that he developed an interest in natural history. In 1871 , while serving at Ft. McHenry, Baltimore, Yarrow met fellow naturalist and surgeon, Elliot Coues. Coues' great interest in ornithology soon infected Yarrow and they spent some time birding before Yarrow moved on to his next assignment at Fort Macon in North Carolina. Coues had also served a stint at Fort Macon where he had taken notes on the local fauna. Yarrow decided to do the same and in 1878, they coauthored an article entitled Notes on the Natural History of Fort Macon. North Carolina and Vicinity in the Proceedings of the Academy of Natural Sciences in Philadelphia.

While serving in North Carolina, Yarrow was presented with an even greater opportunity to study natural history. Upon the recommendation of Spencer Baird of the Smithsonian Institution, he was appointed surgeon and naturalist of an extensive survey of the US, west of the 100th meridian that came to be known as the Wheeler Survey after its leader Lt. George Montague Wheeler.

Our other protagonist, E. D. Cope was born to Quaker parents in 1840 Philadelphia. His father wanted Edward to pursue a career in agriculture, but his strong-minded son was determined to pursue a career in natural history. Eventually his father gave in and supported Edward's ambition. In 1861 he financed a two-year stay in Washington for Edward to carry out informal studies at the Smithsonian Institution. Here the talented Cope soon became a protege of Spencer F. Baird from whom he gained important background in the US herps. However, in 1863 the Civil War was raging and many young men of the North were being conscripted into the Union Army. To save his son from this fate, Edward's father sent him to Europe where Cope had the opportunity to meet and work with some of the leading herpetologists and anatomists of the old world, including John E. Gray and Albert Gunther of the British Museum. He also had opportunity to visit and examine specimens at some of the most renowned museums of Europe (i.e., Paris, Vienna, Berlin).

Upon his return to the States in 1864, despite having no college degree, Cope became a professor of comparative zoology and botany at Haverford College near Philadelphia. He also served as Curator of Herpetology at the Academy of Natural Sciences. More of a researcher than a teacher, Cope found that his teaching duties interfered too much with his studies and writing, precipitating his resignation from Haverford after only three years. His research interests also shifted toward paleontology where he became embroiled in an intense rivalry/feud with a fellow paleontologist O. C. Marsh of Yale, which continued for the rest of his life. It is significant for this article that the feud drove Cope, in his attempts to better Marsh, to become one of the most productive fossil hunters of all time. As the greatest fossil beds were in the western US, he made extensive explorations there (ca. eight months each year) from 1871 to 1893. Many of these expeditions were associated with government surveys of the region. From 1874 to 1875, Cope hired on as the geologist of the Wheeler Survey under the direction of the zoologist for the group, Henry Crecy Yarrow.

Much like John Xantus, Cope did not accept authority well. His fiery temper led to frequent clashes with colleagues and administrators. In addition to his continuing feud with Marsh, Cope had frequent conflicts with administrators at Haverford College and with council members of the Philadelphia Academy of Natural Sciences (which may have precipitated his resignation). His chief challenge on the Wheeler Survey in New Mexico was to keep the army from interfering with his paleontological research. The leader of the expedition, Lt. George Wheeler, was a by-the-book West Point graduate who focused exclusively on topography and geology. Making maps was his priority for the mission, not research. In Wheeler's view, Cope was hired as a geologist, and paleontology should not distract him from this job. Yarrow, Cope's immediate superior, was given the task of keeping him from deviating from his appointed duties. Unfortunately for Yarrow, a team player who followed orders, his mild disposition was ill-suited to handle the rancorous Cope.

An inevitable clash came as Cope was on the verge of making one of the most important discoveries of his career, the Puerco formation in northern New Mexico (renamed Nacimiento), which represented the dawn of the Age of Mammals. Wheeler had not shown any willingness to slow down the progress of the expedition so that fossil beds could be more thoroughly examined. So Cope wrote home complaining: "It is absurd to order stops here where there are no fossils, and marches there where fossil abound." In a subsequent letter Cope told his wife Annie: Yarrow "was not courageous enough to disregard these [orders] and I can not regard them and succeed at my work."

Cope continued to pressure Yarrow to disobey orders until his harried superior threatened to resign. At this point he decided to try a new tact. If Yarrow was going to insist on obeying Wheeler's orders, then Cope would go over Wheeler's head and get new orders. He and Yarrow traveled to Santa Fe to put the issue before the regional commander, General Gregg. Yarrow presented his case and written instructions to Gregg while Cope explained how these orders prevented him from succeeding in his paleontological research. Gregg, who was more sympathetic to scientific research than Wheeler, proceeded to overrule him, siding with Cope. Still problems continued, as Yarrow, trying to hold onto shreds of authority, objected to Cope's demands that they divert the mission to the headwaters of the San Juan River, to search for Eocene formations that likely existed there. Eventually, he overrode the hapless Yarrow's objections and took off with two guides, a collector, and a packhorse. As he had anticipated, Cope found the long sought-after Eocene formations which, according to him, were the most important geological find of his career.

Shortly thereafter, Cope was ordered to report in person to Wheeler. With trepidation, he returned to meet with his superior only to find that Yarrow had given up and left the expedition. One of the party had been killed accidentally and the defeated Yarrow used the excuse of returning to Washington to settle the man's affairs as a way to leave the expedition. He never returned. The delighted Cope was put in charge of the group and given the mules and men he had requested to continue the fossil collecting.

In an 1877 report of the expedition's paleontology, Cope included a 364-page account of the fossils found in the New Mexico formations. Yarrow in an earlier publication, Volume 5 of the U.S. Geographical Surveys: Report of the Expedition for Exploration West of the 100th Meridian, 1875, reported on the mammals, birds and herps. In chapter 4, he described the amphibians and reptiles collected in Arizona, California, Colorado, New Mexico, Nevada and Utah from 1871 to 1874. Interestingly, on page 569 in this report, his oldnemesis , Edward D. Cope, described Sceloporus jarrovii in his honor. Apparently, three specimens collected in southern Arizona by Henry Henshaw, another naturalist on the expedition, were sent to Cope by Yarrow for identification, suggesting that the two had mended fences. The name jarrovii resulted since there is no y or w in Latin and the nearest equivalents, j and v had to be substituted. Possibly, Cope felt somewhat guilty over his previous treatment of Yarrow as he named other species after him as well (e.g., an Eocene mammal, Pelycodus jarrovii and two fish - a sucker, Minomus jarrovii, and a spinedace, Lepidomeda jarrovii).

After his return from the Wheeler Survey, Yarrow became a professor of dermatology at George Washington University. Spencer Baird offered him the honorary position of the first curator of reptiles at the National Museum which he accepted on a part time basis from 1879 to 1889. During his tenure he published the Check list of North American reptilia and amphibia, with catalogue of specimens in the United States National Museum (1883). He also served as an assistant with the US Fish Commission and was one of the founders of the Washington Cosmos Club (a well-known gathering place for scientists). Yarrow died in 1929 and was buried with full military honors at the National Cemetery in Arlington.

Cope continued his consuming rivalry with Marsh, until his death in 1897. Over his career, he named more than 1200 vertebrate species and published 1395 papers (170 on recent amphibians and reptiles). Financially ruined in his final years from privately supporting his expeditions, Cope had to sell his house and move in with his museum specimens at the University of Pennsylvania. A scientist to the end, he left his brain and skeleton to science. The latter eventually ended up in the possession of paleontologist Bob Bakker who in 1993 described it as the type specimen for the species, Homo sapiens. Although a somewhat lesser distinction than to be the type specimen for the human race, the American Society of Ichthyologists and Herpetologists named their scientific journal Copeia in his honor.

SOURCES:
Adler, Kraig A. 1989. Herpetologists of the past. Pp. 5-141 in K. A. Adler (ed.) Contributions to the history of herpetology. Contributions to herpetology, Number 5. Society for the Study of Amphibians and Reptiles.
Burns, Thomas A. 1969. Ecology and physiology of Sceloporus jarrovi in the Graham Mountains, Arizona. PhD dissertation, Arizona State University.
Burns and Hume- Cope, E. D. 1900, The crocodilians, lizards, and snakes of North America. Ann. Rep. Smith.Inst. 1898, Pp. 153-1270.
Hume, Edgar E. 1942. Ornithologists of the United States Army Medical Corps. The John Hopkins Press, Baltimore.
Jaffe, Mark. 2000. The gilded dinosaur, the fossil war between E. D. Cope and O. C. Marsh and the rise of American science. Crown Publishers, New York.
Yarrow, Henry C. 1875. Report upon the collections of batrachians and reptiles made in portions of Nevada, Utah, California, Colorado, New Mexico, and Arizona, during the years 1871, 1872. 1873, and 1874.Chapter IV in G. M. Wheeler. Report upon geographical and geological explorations and surveys west of the one hundredth meridian, Vol. V - Zoology, Washington Government Printing Office.
Woodin, William H. 1953. Notes on some reptiles from the Huachuca area of southeastern Arizona. Bull. Chicago Acad. Sci. 9(15): 285-296