Zwicknia gen. n., a new genus for the Capnia bifrons species group, with descriptions of three new species based on morphology, drumming signals and molecular genetics, and a synopsis of the West Palaearctic and Nearctic genera of Capniidae (Plecoptera)
Author
Murányi, Dávid
muranyi@zool.nhmus.hu
Author
Gamboa, Maribet
maribetg@gmail.com
Author
Orci, Kirill Márk
muranyi@zool.nhmus.hu
text
Zootaxa
2014
2014-06-06
3812
1
1
82
journal article
5365
10.11646/zootaxa.3812.1.1
fd5ba21e-09ce-4ac6-b84f-56632ed93917
1175-5326
4919079
7847D731-9F66-4856-A79F-9435FED25B1D
Capnia
Pictet, 1841
sensu lato
(
Figs. 11–16
,
26–28
,
36–38
)
Capnia
Pictet, 1841
—
Nelson & Baumann 1989: 291
. (revision of the Nearctic species, partly refers to
Arsapnia
Banks, 1897
and
Capnia
Pictet, 1841
sensu stricto
);
Zhiltzova 2003: 318
. (revision of the Palaearctic species (excluded
Japan
and the Himalayan ranges), partly refers to
Capnia
Pictet, 1841
sensu stricto
and
Zwicknia
Murányi
,
gen. n.
).
Species included.
In addition to the species treated as
Capnia
s.s.
above, 1 valid species from the West Palaearctic, 49 from the East Palaearctic, 46 from the West Nearctic and 1 is Transnearctic (
DeWalt
et al.
2014
,
Nelson
& Baumann 1989
); 47 examined (see Appendix 1).
Remarks.
An adequate diagnosis cannot be given for this artificial assemblage of taxa, and the species excluded from the sensu stricto diagnosis will need to be placed in existing or newly erected genera. A revision of these species is out of the scope of the present work, and most of the East Palaearctic species were not studied; some remarks on certain groups can be made on the basis of species examined:
Capnia
s.l.
cordata
species group sensu
Zhiltzova 2001
This group is restricted to the high mountains of Asia with nine known species (
Li & Yang 2009
,
Li
et al.
2011
,
Zhiltzova 2003
); three further species, known from only females, are attributed to this group on the basis of the female genitalia (
Zhiltzova 2003
). Morphologically they form a rather uniform lineage that is closer to
Zwicknia
, but distinctly differs in the males with entire Ep-scl and the lack of Ec (studied in
C. s.l. prolongata
Zhiltzova, 1969
:
Figs. 11–12
), and females have a narrow, dark Sg.
Capnia
s.l.
excavata
and
C. s.l. nana
groups sensu
Nelson
& Baumann 1989
As mentioned above, these
West Nearctic
groups of three and six species (
Nelson
& Baumann 1989
) may belong to the genus
Arsapnia
. The morphology of their epiproct is similar, however, distinctly differ in shape
.
Capnia
s.l.
fialai
Nelson
& Baumann, 1990
In its original description, this Californian,
U.S.A.
species was noted for its resemblance to
Paracapnia
Hanson,
1946
in many features. Recently, it was suggested by
Kondratieff & Lee (2010)
that
C. fialai
could be placed in
Paracapnia
. Despite obvious similarities, we propose to retain it in
Capnia
s.l.
pending further comparative studies, because of the presence of caudal setae on the epiproctal sclerite and tergal processes on Tg 5–7. These features are lacking on other species currently placed in
Paracapnia
. Their inclusion in the generic diagnosis should further restrict the already few diagnostic features of that genus.
Capnia
s.l.
gracilaria
and
C. s.l. vernalis
groups sensu
Nelson
& Baumann 1989
With respect to the structure of their terminalia, these Nearctic groups of four and three species (
Nelson
& Baumann 1989
) probably belong to the genus
Mesocapnia
Raušer, 1968
, with the exception of
C. lacustra
Jewett, 1965
(see below). The distinctive apical spine of the epiproct of
Mesocapnia
was thought to be a compact structure (
Baumann
et al.
1977
,
Raušer 1968
,
Nelson
& Baumann 1989
). However, SEM studies showed that it is a dorsally open structure like the epiproct apex of any other
Capniidae (
Lee & Baumann 2011
)
.
Capnia
s.l.
zukeli
Hanson, 1943
, a species from
Idaho
that was not classified in these species groups by
Nelson
& Baumann (1989)
, probably also belongs to
Mesocapnia
.
Capnia
s.l.
lacustra
Jewett, 1965
This odd species, restricted to Lake Tahoe,
Nevada
,
U.S.A.
is aquatic in both the larval and adult stages, differing from all other
Capniidae
by having Tg 10 entire, and exceptionally reduced ventral thoracic sclerites. The male terminalia is closer to
Mesocapnia
but differ in lacking caudal setae on the epiproct. However, its designation as a separate genus would need further specimens for study. The few available specimens are nearly transparent and morphological details were difficult to ascertain using stereomicroscopes. Specimens were not examined by SEM to avoid damaging these specimens. It is worthy to note that one of the females examined, the entire abdomen and thorax to the cervical region was filled with eggs, a further uniqueness that may be related to the exceptional underwater life of this species.
FIGURES 11–16.
Male terminalia of East Palaearctic
Capnia
s.l.
—11–12:
C. s.l. prolongata
Zhiltzova; 13–14:
C. s.l. pedestris
Kimmins; 15–16:
C. s.l. arensi
Zhiltzova; 11, 13, 15: dorso-caudal view; 12, 14, 16: ventro-caudal view (B-scl: basal sclerite; Ep-scl: main epiproct sclerite (shaded in grey); I-scl: inner sclerite; Tg 10: tergite 10)—not to scale.
FIGURES 17–22.
Male terminalia of Nearctic
Capniidae
—17–18:
Bolshecapnia gregsoni
(Ricker)
; 19–20:
Isocapnia grandis
(Banks)
; 21–22:
Eucapnopsis brevicauda
(Claassen)
; 17, 19, 21: dorso-caudal view; 18, 20, 22: ventro-caudal view (B-scl: basal sclerite; Ec: eversible crest; Ep-scl: main epiproct sclerite (shaded in grey); I-scl: inner sclerite; Lb-scl: laterobasal sclerite; Tg 10: tergite 10)—not to scale.
Capnia
s.l.
nelsoni
Kondratieff & Baumann, 2002
The species was related to the
C. s.l.
decepta
group in its original description, but the authors reluctantly placed it in the above group because of notable morphological differences (
Kondratieff & Baumann 2002
,
Heinold
et al.
2013
). Indeed, its genital characters differ greatly from the diagnosis of
Arsapnia
(
C. s.l.
nelsoni
has large B-scl, Lb-scl divided from Ep-scl and Ep-scl is longitudinally divided), but also cannot placed in any existing groups.
Capnia
s.l.
pedestris
species group sensu
Zwick & Sivec 1980
This group was erected for nine, mainly Central Asian species and two additional species known only from females (
Alouf 1992
,
Zhiltzova 2003
,
Zwick & Sivec 1980
). The main distinguishing character in males is a highly developed, bicuspidate Tg 9. In addition, these taxa are characterized by laterally and dorsally reduced Ep-scl and a large B-scl (
Figs. 13–16
). However, the studied
C. s.l. pedestris
Kimmins, 1946
and
C. s.l. arensi
Zhiltzova, 1964
differ in many features of the terminalia (
Figs 13–16
,
27–28
,
36, 38
), and at least the latter Caucasian-Anatolian species is not monophyletic with the rest of the group.
Capnia
s.l.
spinulosa
Claassen, 1937
This species from
California
,
U.S.A.
has both laterally and ventrally highly divided Ep-scl. The large, complex membranous parts of the epiproct lack I-scl but possess an Ec, and the Fp is fused with Rp. The combination of these genital features does not occur in any of the other species studied during this study, but this taxon may belong to the East Palaearctic genera
Takagripopteryx
or
Capniella
.
Capnia
s.l.
valhalla
Nelson
& Baumann, 1987
Despite superficial resemblance to
Capnia
sensu stricto
, the epiproctal structure of another
California
,
U.S.A.
restricted species, is similar to
Allocapnia
. However, it differs from
Allocapnia
by having a long and narrow Fp, and Sg fused with St 9 but not with Tg 9; the latter feature occur only in
Capnura
Banks, 1900
among the studied taxa (see
Fig. 43
). Most probably, this species should be placed into a separate genus, but comparative studies with the East Palaearctic genera will be needed.
Capnia
s.l.
vidua
Klapálek, 1904
It shares all the characters enumerated in the diagnosis of
Allocapnia
, regarding also to the rather special structure of the epiproct (
Figs. 5–6
,
Tables 1–5
); similarities were already mentioned by
Zwick (1973)
. Its classification in the previously strictly East Nearctic genus would explain its peculiar distribution, as the only stonefly found in
Iceland
. This species additionally has a patchy distribution in southeastern Europe through the N British Isles and NW Scandinavia, with five named subspecies (
Fochetti 2004
,
Hynes 1955b
,
Lillehammer 1972
,
Lillehammer
et al.
1986
,
Vinçon & Sivec 2011
). However, molecular studies do not readily confirm the morphological characteristics, and further studies are needed to clarify the generic placement.