Bulletin, So. Calif. x'\cademy of Sciences Vol. 60. Part 1, 1961 
A NEW TROGLODERUS FROM THE AEOLIAN 
SALINE DUNES OF SOUTHERN CALIFORNIA 
(Notes on North American Coleoptera, No. 15) 
By Charles S. Papp 
The Tenebrionid genus Trogloderus, which is one of the most 
interesting paleo-entomological groups of rare beetles, has been 
treated by Ira La Rivers (1942). The generic relationship in com- 
parison to some of the closely related genera also were discussed 
by him (1948). In another paper La Rivers (1946) modified the 
specific value of all species known at that time, and except for 
costatus LeC, he sank all into subspecific rank. His excellent dis- 
cussion and evaluation of concrete facts and theoretical ideas con- 
cerning the evolution of this remarkable Tenebrionid is a must for 
those who are engaged in the study of our deserts. Here is an 
example of an insect, entirely bound to the ground, with some 
special and as yet unknown processes of complete adaptation to 
the great environmental changes that have occurred. This genus 
could be used as a stepping stone to a greater understanding of 
the evolutionary processes through the ages. 
The geological past of this area often has been discussed by 
several authors (Van Dyke 1932, Spieth 1950, Jaeger 1955, 1957). 
The old fauna probably appeared during the Oligocene or Early 
Miocene, when possibly a broader connection between North and 
South America existed, as a route for the migration of species of 
the southern fauna. Then, when the climate became cooler and the 
once flat land began to rise, a great change took place in this 
territory. The species of warmer origin were exposed to great 
climatic stress. Those that survived began to change in habits and 
also in form. Many of them, however, such as the phytophagous 
forms, could not survive so well, and they .gradually disappeared. 
These environmental changes have been frequently discussed, but 
first hand information, ("on the spot" observations) of this fasci- 
nating problem is needed to understand all those dramatic events 
which give our deserts their thousand faces. The writings of Jaeger 
(1957, etc.) and Spieth (1950) are highly recommended to those 
concerned with North American deserts. 
Sporadically there are a few reports (other than those of La 
Rivers, cited earlier) on Trogloderus from the southwestern 
United States. Most recently Papp and Pierce (1960) reported 
the collection of fairly large numbers of this rare beetle in stored 
32 
Bulletin, So. Calif. Academy of Sciences Vol. 60, Part 1, 1961 
chicken feed in the high desert area of Mojave. These were T. cos- 
tatus tuberculatus Blaisd., collected in September 1958. I did not 
have the good fortune to observe other specimens before or since, 
until I received a large number of beetles (99% Tenebrionids) 
from Dr. W. W. Mayhew, Assistant Professor of Zoology, Uni- 
versity of California, Riverside, Calif. These beetles had fallen 
into his traps that were set for desert reptiles in the aeolian saline 
sand dunes near Dale Dry Lake, San Bernardino County, in the 
Lower Mojave Desert. This interesting habitat is very seldom 
visited by collectors. It is a highly arid portion of the Mojave 
Desert approximately 22 miles east of the desert town of Twenty- 
nine Palms. In this material the writer found 6 specimens of 
Trogloderus, collected on October 16th, 1960. Another two speci- 
mens were picked up with other trapped Tenebrionids by May- 
hew's coworkers (Walter Moberly and Betty Aaron) on Decem- 
ber 23rd, 1960 at the same location. No Trogloderus were found 
in all the trapped material Dr. Mayhew obtained from other areas 
of the desert (Palm Springs and Algodones Dunes). After careful 
study of these specimens, I found this group to be new to science 
and will describe it below. There is now one species (T. costatus 
LeC.) and four subspecies (including this new one) known to 
science, and all are members of the fauna of North America 
(Papp, 1961 -a). 
Trogloderus costatus mayhewi Papp, new subspecies (Plate 
11). — It is easily recognized by its black color, strongly de- 
veloped longitudinal ridges on the elytra and by its broad prono- 
tum. — The Head is slightly wider than long, very coarsely, irreg- 
ularly granulate. The transverse impression of the vertex deep at 
base; on the deepest anterior edge very finely at the shallower 
posterior edge very coarsely granulate. The central elevation with 
rough granulation is slightly divided by an irregular short groove. 
The pre-ocellar edge widely rounded, labial margin slightly curved, 
heavily granulated. Eyes small, deeply set and partially covered by 
the end of the transverse groove of vertex. — Pronotum as wide 
(?) or wider { $ ) than the elytra on its widest point. Lateral 
margin evenly rounded, slightly wider behind middle, more or 
less evenly annulated; the annules somewhat sharp and each annule 
with a short but strong black seta (which can not be indicated on 
the enclosed illustration). Anterior angles sharp, pointed, with a 
deeply set anterior, and with a more or less even posterior margin, 
with a short but sharp posterior angles. Sides broad, almost flat, 
very coarsely granulated; just before the elevated center portion 
begins with large irregularly shaped impressions with sharp and 
shiny edges. The elevated portion similarly but somewhat finely 
granulated, with a shallow transverse impression, which occasion- 
ally in deeper in its posterior end. — ■ Elytra as wide ( 5 ) or 
slightly wider ( 5 ) than the pronotum, with four prominent 
Bulletin, So. Calif. Academy of Sciences 
Vol. 60, Part 1, 1961 
PLATE 11 
Trogloderus costatus mayhezvi Papp, new subspecies. 
(Drawing by the author) 
34 
Bulletin, So. Calif. Academy of Sciences Vol. 60, Part 1, 1961 
longitudinal ridges, from which the two external costa shallow, the 
others gradually higher toward the middle of the elytra, the 
fourth is the highest. All the ridges are continuous, shiny, slightly 
uneven in their longitudinal line. The caudal ends shallow and are 
individual endings. The intercostal spaces are sharply concave, 
more or less opaque, with a very slim remains of shallow punc- 
tures, which are hardly visible on some specimens. There are no 
setae present. — Legs, especially the anterior pair, roughly granu- 
late, the others smoothly punctulated, all on their ventral side with 
golden, sharp setae. The pro femora with a blunt tooth, the protibiae 
with a broad tooth dorsally and with two narrower ones ventrally. 
— Abdomen flat, somewhat concave, sides smoother, other parts 
finely granulated and sporadically covered with short golden yel- 
low setae. — Length: Males 8.0-11.7 mm., Females 9.5-13.5 mm. 
Locality : Dale Dry Lake, southern San Bernardino County 
(the lower Mojave Desert area), California. Six specimens were 
collected on October 16, 1960, two specimens on December 23, 
1960. The area was generally discussed in another paper (Papp, 
1961-b) in connection with the description of a new Saprinus. — 
Type (male) deposited in the type collection of the Department 
of Entomology, Los Angeles County Museum, Los Angeles, Calif.; 
female specimen deposited at the same place. — , Paratypes : One 
specimen in the collection of the Division of Life Sciences, Uni- 
versity of California, Riverside, Calif.; one specimen in the British 
Museum (Natural History), London, England; one specimen in 
the Rijksmuseum van Natuurlijke Historic, Leiden, Nederland; 
one specimen in the collection of the Swedish Academy of Sciences, 
Rijksmuseum, Stockholm, Sweden. 
Specimens of Trogloderus costatus tuberculatus Blaisd. also 
have been sent to the above mentioned institutions, plus the Mu- 
seum Georg Frey, Tutzing bei Miinchen, Germany. 
BIBLIOGRAPHY CITED 
AscHMAN, Homer (1959) : The evolution of a wild landscape 
and its persistence in southern California. — Ann. Assoc. 
Amer. Geogr. 49 (3, part 2) :34-57, 15 figs. 
Jaeger, E. C. (1955) : The California Deserts. — Stanford Univ. 
Press, 3rd edition, 211 pp., illustrated. 
Jaeger, E. C. (1957) : The North American Deserts. — Stanford 
Univ. Press, 308 pp., 355 figs. 
La Rivers, Ira (1942) : A new Trogloderus from Nevada, with a 
key to the known species. — Ann. Ent. Soc. Amer. 35 (4) : 
435-440. 
35 
BuLLETix, So. Calif. Academy of Scie>-ces Vol. 60, Part 1, 1961 
La Rivers, Ira (1946) : On the genus Trogloderus LeConte. — 
Ent. News, 57(2) :35-44. 
La Rivers, Ira (1948): Notes on the Eleodini. — Ent. News 
59(4) :96-101, 1 map. 
Pallister, J. C. (1954) : The Tenebrionid beetles of North Cen- 
tral Mexico collected on the David Rockefeller Mexican Ex- 
pedition of 1947. — Amer. Mus. Novit. No. 1697, 55 pp., 
12 f^gs. 
Papp. C. S. (1961a) : Checklist of Tenebrionidae of North Amer- 
ica. North of the Panama Canal. — Opusc. Ent., 26(1) :l-44. 
Papp, C. S. (1961b) : Saprinus mayhewi new species and distri- 
butional records on other American Histeridae. — Ent. Ber. 
(in press). 
Papp, C. S. and H. D. Pierce (1960) : Ecological remarks on 
some Tenebrionids connected with stored animal food in the 
Mojave Desert, California. — Journ. Kans. Ent. Soc, 
33(4) :154-156, 5 figs. (Fig. 2: Trogloderus costatus tuber- 
culatus Blaisd.) 
Pierce, W. Dwight (1957): Insects. — Geol. Soc. of Amer., 
Memoir 67 :943-952. 
Spieth, H. T. (1950) : The David Rockefeller Mexican Expedi- 
ition of the American Museum of Natural History. Intro- 
ductory accaunt. — Amer. Mus. Novit. No. 1454, 67 pp., 
52 figs. 
Van Dyke, E. C. (1933) : Peculiarities of the Coleopterous fauna 
of semiarid southwestern North America. — Ve Congres In- 
ternal. d'Ent., Paris 1932, p. 471-477. 
36