Submitted to: Annales Zoologici
Department of Entomology and
University of Florida
P.O. Box 110620
Gainesville, FL 32611-0620
A NEW SPECIES OF PETALACMIS FIREFLY (COLEOPTERA: LAMPYRIDAE)
FROM BOLIVIA WITH A KEY TO THE KNOWN SPECIES OF THE GENUS.
MARC A. BRANHAM
Department of Entomology and Nematology
University of Florida
P.O. Box 110620
Gainesville, FL 32611-0620
A new species of Petalacmis firefly, P. triplehorni, is described from Bolivia and
compared to the other two described species in this genus. Illustrations of the male dorsal
and ventral habitus are included as well as a key to the known species of this genus.
Key Words: Lampyridae, Petalacmis, Lampyrini
The genus Petalacmis is an interesting and unique genus in the family Lampyridae due to
its a distinctive antennal morphology. Members of this genus have only nine
antennomeres with the ninth being very elongate and paddle-shaped. Petalacmis is
restricted to South America and presently consists of two species, P. praeclarus, known
from Brazil, Bolivia and Peru and P. wittmeri known only from Brazil. Here a third
species, P. triplehorni is described; it is only known from Bolivia.
MATERIALS AND METHODS
Petalacmis triplehorni Branham, new species
Description.- Male: General coloration of specimens: antennae light brown turning to a
dark tan towards the apex of the ninth antennomere; eyes black, head dark brown with
mouthparts tan; pronotum yellowish-tan with a dark brown to black discal region;
scutellum and legs tan; elytra dark brown.
Length: 5.0mm, maximum width 0.7mm.
Head: hidden from above by pronotum; eyes large, not ventrally contiguous; mandibles
of the specialized type found in Lampyrini; maxillary palps 4-segmented; apex of 4th
segment narrowing to form a conical spike-like projection; antennae 9-segmented, with
the last antennomere greatly elongated and blade-like; antennomeres 3-8 wider than long,
with 5 and 7 being wider than 6 and 8, with the width of 7 and 8 approximating the width
Pronotum: wider than long, dorsal surface moderately punctate and covered with medium
length setae; anterior edge is slightly pointed, sides roughly parallel, base emarginate
with posterior corners and medial edge extending farther back than the rest of the hind
margin; all external borders curved upwards, forming a depression between the disc and
pronotal borders; discal region is moderately punctate, sub-rectangular.
Scutellum: triangular and bearing few setae.
Elytra: slightly wider than pronotum; explanate margins narrow, extending from the
humerus to about one quarter of the length of the elytra, dark brown throughout; elytral
Legs: compressed; tibial spurs lacking; claws simple.
Abdomen: ventral abdominal segments 2 to 5 dark brown to black, 6 and 7 with the
medial one half of the ventral surface covered by photic organs, 8 and 9 very light in
Etymology. This species is named for Dr. Charles Triplehom, the Ohio State
University, who collected the first specimens ofPetalacmis (Petalacmispraeclarus) the
author first encountered as a graduate student while investigating the systematics of the
family Lampyridae. Dr. Triplehom has been both a mentor and an inspiration to me. It is
with great appreciation and respect for Dr. Triplehorn that I name this species after him.
Material Examined. Holotype, male: Bolivia: Santa Cruz, 3.7km SSE of Buena Vista,
Hotel Flora and Fauna, 405m. 5-15-XI-2001, 1729.949'S; 63033.152W, coll. M.C.
Thomas & B.K. Dozier, tropical transition forest.
Paratypes, males: Bolivia: (6 males) Santa Cruz, 3.7km SSE of Buena Vista, Hotel Flora
and Fauna, 405m. 5-15-XI-2001, 1729.949'S: 63033.152W, coll. M.C. Thomas & B.K.
Dozier, tropical transition forest; (2 males) Santa Cruz, 3.7km SSE ofBuena Vista, Hotel
Flora and Fauna, 430m. 5-15-XI-2001, 1729.949'S: 63033.152W, coll. M.C. Thomas,
Blacklight trap, tropical transition forest; (3 males) Santa Cruz, 3.7km SSE of Buena
Vista, Hotel Flora and Fauna, 430m. 2-13-III-2000, coll. M.C. Thomas, tropical transition
forest; (1 male) Santa Cruz, 3.7km SSE of Buena Vista, Hotel Flora and Fauna, 430m.
14-19-X-2000, coll. M.C. Thomas, tropical transition forest.
Petalacmis was erected for the species P. praeclarus by Olivier in 1908. In a later work
(Olivier 1910) he placed the genus in subfamily Photininae. Green (1959) redefined the
tribe Lampyrini and limited it to only those genera that possessed a mandible of the
"modified" type. Green defined this type of mandible as "small, more or less porrect,
coarsely pubescent externally, and with quite slender glabrous tips that are variably
discontinuous in curvature with the rest of the mandible." In this 1959 work, Green
moved Petalacmis to the superfamily Lampyrinae and the tribe Lampyrini. Green's
placement of Petalacmis was followed in McDermott's subsequent taxonomic work on
Lampyridae (1964) and his 1966 catalog.
The locality data for Olivier's P. praeclarus is simply "Brazil." It has since been
collected in Bolivia and Peru (Olivier 1908; Reichardt 1963;McDermott 1964, 1966,
Lawrence et. al. 2001). In 1964, Reichardt described the second species, P. wittmeri
which was collected at Estado do Para, Ananindena, Brazil. P. triplehorni n. sp. was
collected near Buena Vista, Santa Cruz, Bolivia. The three species of Petalacmis are
easily diagnosable by size (Table 1), antennal morphology (Fig. 4), and the shape of
Key to the Species of Petalacmis
1. Elytra with outer edges (when folded) roughly parallel, elytron generally of equal
width across its length, tapering slightly toward the distal tip.......................2
1'. Elytra with outer edges (when folded) not parallel, elytron widest in middle and
tapering at proximal and distal tips.................Petalacmis wittmeri Reichardt
2(1). Elytral explanate margin extending one half to two thirds of elytral length and
yellowish, antennomeres 5 and 7 being equal in width to 6 and 8.
Petalacmis praeclarus Olivier
2'. Elytral explanate margin extending one third of elytral length and the same color as
the rest of the elytron brown, antennomeres 5 and 7 being wider than 6 and 8.
Petalacmis triplehorni new species
Due to the presence of large eyes and photic organs in the male, one might expect that
both the male and female of these species are luminous and use luminous signals for pair-
formation. The large size of these photic organs in the males and the fact that they cover
most of the sternite indicate that they most likely produced "flashed" signals rather than
"glows" (Branham and Wenzel 2003). Due to the fact that no females are currently
known for any of the three species in this genus might suggest that they are sedentary,
perhaps brachypterous or even apterous. Alternatively, these species may be so
uncommonly encountered that no females have been collected.
Charles Triplehom for collecting the specimens that made me aware of this genus and for
being the great friend and mentor that he is. Cleida Costa for comparing the new species
to the holotype of P. wittmeri. Michael Thomas for collecting the series of specimens
described in this manuscript and making them available for to study. James E. Lloyd
and Paul "Skip" Choate for commenting on a draft of the manuscript and Ale Maruniak
for help translating Spanish. The holotype ofPetalacmis triplehorni is deposited in the
Museo de Historia Natural, Departamento Entomologia, Santa Cruz de la Sierra, Bolivia;
paratypes are held at the Florida State Collection of Arthropods, Gainesville, FL (FSCA),
the Ohio State University, Columbus, OH (OSUC), the Museu de Zoologia, Universidade
de Sao Paulo, Sao Paulo, Brazil (MZSP) and the personal collection of Marc A. Branham
(MABC). This is the University of Florida Agricultural Experimental Station journal
Branham, M.A. and J.W. Wenzel 2003. The origin of photic behavior and the evolution
of sexual communication in fireflies (Coleoptera: Lampyridae). Cladistics
Green, J.W. 1959. Revision of the species of Microphotus with an emendation of the
Lampyrini (Lampyridae). Coleopterists' Bulletin 13: 80-96.
Lawrence, J.F., A.M. Hastings, M.J.Dallwitz, T.A. Paine and E.J. Zurcher 2001.
Elateriformia (Coleoptera): Descriptions, Illustrations, Identification, and
Information Retrieval for Families and Sub-families. Version: 22nd December
McDemott, F.A. 1964. The taxonomy of Lampyridae (Coleoptera). Transactions of the
American Entomological Society. 90: 1-72.
McDermott, F.A. 1966. Pars 9 Lampyridae. In: W.O. Steel (ed.), Coleopterorum
Catalogus Supplementa. W. Junk, The Hague, 149pp.
Olivier, E. 1908. Description d'un nouveau genre et d'une nouvelle espece de
Lampyrides (Col.). Bulletin de la Societe Entomologique de France 1908: 186-
Olivier, E. 1910. Pars 9. Lampyridae. In: S. Schenkling (ed.). Coleopterorum Catalogus.
W. Junk, Berlin, 68pp.
Reichardt, H. 1963. Notas sobre el genero Petalacmis, con description de una especie
nueva (Coleoptera, Lampyridae). Neotropica 9: 107-110.
List of Tables:
Table 1. Comparative measurements between the three known species of Petalacmis.
List of Figures:
Figure 1 and 2. Petalacmis triplehorni n. species, male, 1. dorsal habitus. 2. ventral
Figure 3. Petalacmis triplehorni n. species, male, pronotum, dorsal view.
Figure 4. Comparison between the antennal morphologies of a) Petalacmispraeclarus, b)
Petalacmis wittmeri, and c) Petalacmis triplehorni, scale bar = 1.0mm
Dimensions (mm) P praeclarus P wittmeri P. triplehorni
Total Length: 8.6 6.8 5.0
Pronotal Length: 1.8 1.5 1.0
Pronotal Width: 2.5 2.2 1.3
Elytral Length: 6.8 5.3 4.0
Greatest Elytral Width: 3.1 3.4 0.7