Neotropical Mecoptera (Insecta): New generic synonymies, new combinations, key to families and genera, and checklist of species
Author
Machado, Renato Jose Pires
Author
Godoi, Fabio Siqueira P.
Author
Rafael, José Albertino
text
Zootaxa
2009
2148
27
38
journal article
40809
10.5281/zenodo.275008
22dec5a8-3bff-4088-9b50-b4ba1ce5494d
1175-5326
275008
Bittacus
and
Thyridates
The genus
Bittacus
was created for the European species,
B. italicus
(Müller, 1766)
(=
B. tipularia
(Fabricius, 1775)
. Subsequent to that, the first New World species,
B. stigmaterus
Say, 1823
, was described. Nowadays
Bittacus
is the most diverse genus of
Bittacidae
, with species in all biogeographical regions.
Navás (1908)
proposed the creation of the genus
Thyridates
for
Bittacus chilensis
Klug, 1838
, but Esben-
Petersen (1921)
considered the differentiating characters proposed by Navás inconsistent and synonymized
Thyridates
with
Bittacus
, which was accepted by subsequent authors (
Byers 1972
;
Penny 1975
;
Penny & Byers 1979a
,
b
).
The synonymy between
Thyridates
and
Bittacus
was questioned by
Willmann (1983)
, who proposed the revalidation of
Thyridates
and transferred 12 species from
Bittacus
to it. This author pointed out two characters to support the group: the origin of Rs1+2 forming nearly a right angle and extra costal crossveins present beyond the humeral crossvein. In the same paper the author also used a biogeographical discussion to support his hypothesis, pointing out that
Bittacus
is broadly distributed in Eurasia and North
America
(Laurasian distribution) but does not occur in the Australian region, and thus,
Bittacus
cannot be the predominant genus of
Bittacidae
in South
America
.
Collucci and Amorim (2000
,
2001
) adopted Willmann’s classification, described four new species of
Thyridates
, and transferred another three species from
Bittacus
to
Thyridates
. These authors pointed out that
Bittacus
is probably Holarctic, while
Thyridates
is a Neotropical genus. They also proposed another five synapomorphies to emphasize the consistency of the group: fork of Rs more basal than the apex of Sc; crossvein sc-r apical; thyridium evident; pterostigma elongate; and species relatively large.
Petrulevičius (2003)
reiterated the consistency of
Thyridates
and discussed the characters introduced by
Willmann (1983)
and
Collucci and Amorim (2000)
. The author considered two of the characters as least problematic: origin of Rs1+2 making nearly a right angle as proposed by
Willmann (1983)
, and elongated pterostigma as proposed by
Collucci and Amorim (2000)
; he emphasized that the strongest character was the presence of two or three pterostigmal crossveins, which distinguish an elongated pterostigma (
Fig. 1
). In addition to these two characters
Petrulevičius (2003)
also proposed one more: presence of a forked
Kreuz der Bittaciden
(bifurcations of veins Rs3+4, M1+2 and M3+4, arising at the same level, where the bifurcation in M1+2 becomes more basal, almost at the same level as crossveins rs4-m1+2 and m1+2-m3+4). Based on these three characters the author described a fossil species from
Argentina
(
Thyridates novokschonovi
Petrulevičius, 2003
) and transferred seven African species from
Bittacus
to
Thyridates
, thus expanding the geographical distribution of
Thyridates
.
He suggested a Gondwanan origin for the group, before it became restricted to the Neotropical region.
Although these authors considered
Thyridates
a valid genus and introduced some putative synapomorphies, other authors have ignored these works and have not accepted
Thyridates
(
Byers 1996
,
2004
;
Byers & Roggero 1992
), which has caused nomenclatural instability.
For the development of this work we have examined specimens of 25 species (see examined specimens below) from the New World, mainly to analyze the three characters pointed out by
Petrulevičius (2003)
. The first one, the origin of Rs1+2 at nearly a right angle, is the most constant character state among the South American species now classified in
Thyridates
. However, this character state is not present in all species from South
America
and Africa (
Petrulevičius 2003
) and also can be found in some Nearctic species of
Bittacus
, such as
B. chlorostigma
MacLachlan, 1881
,
B. occidentis
Walker, 1853
,
B. pilicornis
Westwood, 1846
,
B. punctiger
Westwood, 1846
, and
B. stigmaterus
Say, 1823
. The second character state, an elongate pterostigma with two or three crossveins, is also variable.
Bittacus maculosus
Byers, 1965
,
B. diversinervis
Souza Lopes & Mangabeira, 1942
,
B. pintoi
Souza Lopes & Mangabeira, 1942
, and
B. femoralis
Klug, 1838
contain specimens with only one crossvein and sometimes with one crossvein on one side of the body and two or three on the other side. Other genera, such as
Pazius
and
Kalobittacus
, also share this character state. The third character, the presence of a forked
Kreuz der Bittaciden
, occurs practically in all species of
Thyridates
and
Bittacus
that we have examined, but in the majority of them the bifurcation M1+2 is a little more apical than the others, and does not reach the level of crossveins rs4-m1+2 and m1+2 -m3+4, the opposite of what
Petrulevičius (2003)
indicated and exactly the same as occurs in some
Kalobittacus
species.
The biogeographical discussion in
Willmann (1983)
was strongly based on the absence of
Bittacus
in the Australian region to explain why
Bittacus
could not occur in the Neotropical region. However this conclusion no longer can be considered valid as
Lambkin (1988)
has described the first Australian
Bittacus
(
B. eremus
Lambkin, 1988
).
The Andes Mountains is one of the most formidable biogeographical barriers for insects in South
America
. The mecopteran fauna in the lowlands west of the Andes is almost completely different than that east of the Andes; only
Bittacus
occurs in both regions, but with just a single species,
B. chilensis
, on the west side. This species, the basis for
Thyridates
(
Navás, 1908
)
, has some peculiar characteristics, such as the large body size and large eleventh tergite. When a comprehensive phylogenetic study related to all of these taxa is done we may have to reconsider resurrection of
Thyridates
, but only for this particular species, not for the others.
Because of the inconsistency of the three characters discussed we opt to not accept
Thyridates
as a valid genus, as Esben-Petersen had concluded in 1921. Thus, we transfer to
Bittacus
all species recently described in
Thyridates
:
Bittacus brunnipenis
(
Collucci & Amorim, 2000
)
n. comb.
,
B. froehlichi
(
Collucci & Amorim, 2000
)
n. comb.
,
B. latreillei
(
Collucci & Amorim, 2000
)
n. comb.
,
B. novokschonovi
(
Petrulevičius, 2003
)
n. comb.
and
B. willmanni
(
Collucci & Amorim, 2001
)
n. comb.
.
As
Thyridates
is again synonymized with
Bittacus
all of the African species that Petrulevičius transferred to
Thyridates
must again be treated in
Bittacus
:
B. chevalieri
Navás, 1908
,
B. erythrostigma
Byers, 1975
,
B. nebulosus
Klug, 1838
,
B. oreinus
Navás, 1914
,
B. stanleyi
Byers, 1968
,
B. testaceous
Klug, 1838
, and
B. weelei
Esben-Petersen, 1913
.