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A New Species of Xenotriphleba Buck (Diptera: Phoridae) fromBaltic AmberAuthor(s): Brian V. BrownSource: Proceedings of the Entomological Society of Washington, 111(1):33-37.2009.Published By: Entomological Society of WashingtonDOI: http://dx.doi.org/10.4289/0013-8797-111.1.33URL: http://www.bioone.org/doi/full/10.4289/0013-8797-111.1.33
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A NEW SPECIES OF XENOTRIPHLEBA BUCK (DIPTERA: PHORIDAE)FROM BALTIC AMBER
BRIAN V. BROWN
Entomology Section, Natural History Museum of Los Angeles County, 900
Exposition Boulevard, Los Angeles, CA, 90007, U.S.A. (e-mail: firstname.lastname@example.org)
Abstract.A new fossil species of the enigmatic genus Xenotriphleba Buck, X.antiqua, is defined from a single specimen in Baltic amber. Its differences from andsimilarities with the single extant species, X. dentistylata Buck, are discussed.
Key Words: Diptera, Phoridae, Xenotriphleba, fossil, amber
The genus Xenotriphleba Buck is one of
the most unusual non-metopinine phorids
that has been described in recent years.
Because specimens of the sole species, the
European X. dentistylata Buck, bear a
suite of characters that make their rela-
tionship to other phorid genera highly
problematic, Buck (1997) tried but was
unable to place them within the systematic
framework proposed by Brown (1992).
Specimens of X. dentistylata Buck are
rarely collected, and their natural history
is unknown. The type series included
specimens found in Germany and Swit-
zerland, and there are additional male
specimens in the collection of the Natu-
ral History Museum of Los Angeles
County (LACM) from Russia (near
Moscow) and far eastern Russia (see
also similar records in Michailovskaya
2004). Records of occurrence in Hungary
(Papp 2002) and Poland (Durska et al.
2005) further indicate the widespread
distribution of this species.
Because of the systematic questions
raised by this enigmatic genus, the
discovery of a fossil specimen is of great
interest. The new species is defined
below, with emphasis on differences
from X. dentistylata.
Xenotriphleba Buck, 1997: 351. Type
species: Xenotriphleba dentistylata
Buck, by original designation.
Xenotriphleba dentistylata Buck
Xenotriphleba dentistylata Buck, 1997:
Material examined.RUSSIA: Mos-
cow, Friazevo, 55.75uN, 37.70uE, 1-,25.vii.2000, M. Tretiakov, Malaise trap
in garden; Primoskiy krai, Gornotayozh-
noye, 43.66uN, 132.25uE, 1 -, vii.2000,M. Michailovskaya, yellow pan trap
Xenotriphleba antiqua Brown,new species
Recognition.This fossil is classified
in the genus Xenotriphleba based on the
presence of large tibial setae, one pair of
reclinate supra-antennal setae, large
rounded surstyli with thick, peglike setae
medially, and the lack of wing vein* Accepted by David R. Smith
PROC. ENTOMOL. SOC. WASH.
111(1), 2009, pp. 3337
Figs. 12. Xenotriphleba antiqua. 1, Head, anterior. 2, Right wing, dorsal.
34 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON
A1+CuA2. It differs from the definitionof X. dentistylata by the much larger
body size, the presence of wing vein R2+3,
the presence of a long foretibial seta, and
other details listed in the description and
Description of holotype.Body
length 3.2 mm (not including termina-
lia). Frons relatively narrow, approxi-mately 0.34 head width (Fig. 1). Usual
12 frontal setae (arranged 4-4-4) present,
plus one pair of reclinate supra-antennal
setae (Fig. 1). Flagellomere 1 oval,
slightly pointed, arista dorsal, preapical.
Palpal setae relatively short. Anepister-
num bare, without furrows. Scutellum
with two subequal pairs of setae. Winglength 2.85 mm. Costa 0.56 wing length.
Vein R2+3 present (Fig. 2). First costal
sector not measurable, second costal
sector (insertion of vein R1 to insertion
of vein R2+3) 1.8 times length of sector 3
(R2+3 to end of costa). Vein Rs notthickened, with row of about 20 extreme-
ly short, widely spaced setae extending to
approximate level of vein R2+3. Vein
A1+CuA2 (fourth thin vein) not visible(Fig. 3). Foretarsomeres elongate, not
shortened as in X. dentistylata. Foretibia
with one long dorsal seta near midlength
and eight smaller ones more distally(Fig. 3). Midtibia with pair of setae near
base, one anterior and one posterior, and
one long anterior seta near apex; apical
seta clearly longer than width of tibia.
Hind tibia with two long anterodorsal
setae, one slightly basal to midlength and
one near apex (Fig. 3), and one poster-
odorsal seta near base. All tibiae lackingsetal palisades and ctenidia. Male termi-
nalia largely obscured (on left side by
lobelike distortions of the abdominal
membrane), but small rounded cercus
and large surstyli visible (Fig. 4), as in X.
Fig. 3. Xenotriphleba antiqua, habitus, left lateral (blank areas obscured by milky substance in amber).
VOLUME 111, NUMBER 1 35
dentistylata. Medial surface of at least
left surstylus with peglike setae (Fig. 5,
only visible from right side by tilting
Derivation of species name.From
Latin antiquus for old.
Holotype.-, Baltic amber, localityunknown, specimen number G 1283,
University of Gottingen collection, Ger-
Systematic affinities.Buck (1997)
proposed some apomorphic characters
for genus Xenotriphleba based on male
and female specimens of X. dentistylata.
Three of these were given as definite apo-
morphies of the group: absence of vein
R2+3, absence of vein A1+CuA2, andstructure of female tergite 6. Based on X.
antiqua, however, the absence of vein R2+3might have occurred after the origin of the
genus, in the lineage leading to X. dentis-
tylata only. Similarly, the lack of a
dorsobasal foretibial seta in X. dentistylata
may be the result of a loss of this structure
after the origin of Xenotriphleba.
Many of the character states in which
X. antiqua visibly differs from X. dentis-
tylata seem to be present in a primitive
state in X. antiqua (Table 1). One inter-
esting character in this regard is the
presence of a nearly complete row of
setulae along the dorsal surface of vein
Figs. 45. Xenotriphleba antiqua, male terminalia. 4, Left lateral. 5, Apex, right lateral.
Table 1. Comparison of character states in specimens of extinct fossil Xenotriphleba antiqua and
extant X. dentistylata.
Character State X. antiqua X. dentistylata
body length large (3.2 mm) small (1.3 mm)
frontal width narrow (0.34 head width) broad (0.61 head width)
palpus with short setae with long setae
anterior scutellar seta subequal to posterior much smaller than posterior
vein R2+3 present absent
vein Rs setulose with one basal seta
vein Rs thin thickened
foretibia with dorsal seta without setae
foretarsomeres elongate short
36 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON
Rs. Although this character is useful for
separating some modern genera (such asAnevrina Lioy and Aenigmatias Meinert),
it is also unexpectedly present in some
fossil species of modern genera that lack
it, such as Hypocera Lioy and Chaeto-
pleurophora Schmitz (Brown in press).
Possibly this character was a groundplan
condition of the common ancestor of
these groups. Some primitive charactersof X. antiqua, such as the presence of
vein R2+3 and the setulose Rs, are also
found in another phorid with separate,
subequal surstyli, Burmophora Beyer, a
genus that Brown (1992) proposed re-
tained the most primitive male surstyli
known at the time.
Characters that might be apomorphic inX. antiqua, relative to X. dentistylata, are
the narrow frons and the short setae of the
palpus. Without detailed knowledge of the
outgroup of Xenotriphleba, however, it is
difficult to know whether these characters
are truly apomorphic within the genus.
Unfortunately, the new fossil species
does not give us any new insights into theclosest relatives of Xenotriphleba. The
ancestry of phorid genera is a question
being addressed using molecular data by B.
Brown and P. Smith (in preparation), after
preliminary work by Cook et al. (2004).
Illustrations were skillfully producedby Brian Koehler. I thank Mike Reich
for the loan of phorid specimens in
amber from the collection in Gottingen,Germany, G. Kung for commenting on
an earlier version of the manuscript, and
reviews by M. Buck and H. Disney. My
research on non-metopinine phorids is
funded by NSF grant DEB 0516420 to B.
Brown and P. Smith.
Brown, B. V. 1992. Generic revision of Phoridae of
the Nearctic Region and phylogenetic classifi-
cation of Phoridae, Sciadoceridae and Irono-
myiidae (Diptera: Phoridea). Memoirs of the
Entomological Society of Canada, No. 164,
. In press. Novel character states in fossil
species of modern phorid genera (Diptera:
Phoridae). Studia Dipterologica.
Buck, M. 1997. A new genus and species of
Phoridae (Diptera) from central Europe with
remarkably primitive male genitalia. Entomo-
logica Scandinavica 28: 351359.
Cook, C. E., J. J. Austin, and R. H. L. Disney.
2004. A mitochondrial 12 s and 16 s rRNA
phylogeny of critical genera of Phoridae
(Diptera) and related families of Aschiza.
Zootaxa 593: 111.
Durska, E., E. Kaczorowska, and R. H. L. Disney.
2005. Scuttle flies (Diptera: Phoridae) of saline
habitats in the Gulf of Gdansk, Poland.
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tera: Phoridae) of the Far East of Russia.
Russian Academy of Sciences, Far Eastern
Branch, V. L. Komarovs Mountain-Taiga
Station. Dalnauka, Vladivostok. 148 pp.
Papp, L. 2002. New records of Phoridae (Diptera)
from Hungary. Folia Entomologica Hungarica
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