Page 18 - Black Range Naturalist Vol. 4 No. 1

The Covers
Megetra punctata, a blister beetle, graces the front cover of this issue. The photographs on the front cover and below were taken on August 22, 2016 in Hillsboro, New Mexico. The species is typically seen between July and September. In the U. S. this species is generally found at elevations between 4,000 and 5,000 feet (photographed at about 5,200’). In Mexico it is found at elevations as high as 8,500 feet. The range of this species is limited to south-eastern Arizona and southwestern New Mexico in the United States and to Chihuahua, southwestern Coahuila, and southern Durango in Mexico - a range which is close to that of the species discussed below. There are two other species in the genus, both have similar ranges to M. punctata.
A photograph from April 16, 2015, of an individual of the Cysteodemus wislizeni species, graces the back cover. This species is generally seen between May and September. The photograph was taken just east of Hillsboro, New Mexico. The English common name for the genus Cysteodemus is Desert Spider Beetle. The English common name for C. wizlizeni rolls off the tongue like honey - Black Bladder-bodied Meloid. There are two species in this genus in the United States, this one is native to the Chihuahuan Desert, which basically defines its range. The other species, C. armatus, is native to the Mojave Desert.
Estefany Karen López-Estrada, Isabel Sanmartín, Mario García- París, and Alejandro Zaldívar-Riverón recently performed research on the question of why blister beetles show low species diversity (there are few species) and “wild body-shape variation”. They published their findings in “High extinction rates and non-adaptive radiation explains patterns of low diversity and extreme morphological disparity in North American blister beetles (Coleoptera, Meloidae)”; Molecular Phylogenetics and Evolution, Vol. 130; January 2019; pp 156-168. The graphic below is from that article.
They found that during the extinction event which occurred between the Miocene and Pliocene most of the diversity previously seen in this family (Meloidae) was extinguished (extinction is forever). Subsequent to that “extinction event” the remaining species underwent rapid morphological changes without species diversification. Thus, when walking in the Black Range, you may find beautiful examples of species which survived a major ecological disaster, underwent significant morphological change, but did not generate significant numbers of new species.
The “back stories” of the species we regularly encounter in the Black Range often provide key insights into the natural history we find about us today.
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