Sycacantha Diakonoff, 1959 from China, with the descriptions of three new species (Lepidoptera: Tortricidae: Olethreutinae)
Author
Feng, Weixing
Author
Zhuang, Jialiang
Author
Yu, Haili
text
Zootaxa
2019
2019-10-31
4691
3
201
214
journal article
25005
10.11646/zootaxa.4691.3.1
58e8ba53-f212-404c-854c-118eff908d2c
1175-5326
3527207
250A8564-B653-40F7-8B11-7391760FE839
Sycacantha
Diakonoff, 1959
Sycacantha
Diakonoff, 1959: 181
.
Type
species:
Phaecasiophora
(
Sycacantha
)
auriflora
Diakonoff, 1959
(described as subgenus of
Phaecasiophora
).
Sycacantha
Diakonoff, 1966: 7
.
Type
species:
Phaecasiophora
(
Sycacantha
)
auriflora
Diakonoff, 1959
.
Species of
Sycacantha
are medium-sized moths that are easily distinguished from other Olethreutini by the mottled forewing pattern, often with a curved subapical band with short, parallel black lines. However, this wing pattern can also be found in some species of
Phaecasiophora
and
Atriscripta
. The deeply cleft socii of the male genitalia are diagnostic for
Sycacantha
and distinguish it from all other genera of Sycacanthae (sensu
Diakonoff, 1973
).
Species of
Sycacantha
usually have the following combination of characters. In the male genitalia the uncus is reduced or rudimentary, dome-shaped or cone-shaped; the socius is deeply cleft forming two processes of different size, covered with spines evenly or apically; the gnathos is a naked transversal band, weakly or strongly sclerotized; the valva is slender, with a bristled costal hump basally, neck distinct, or constricted in varying degree, cucullus with base projecting ventrally, like an elbow of valva; and the phallus is short, with cornuti usually a cluster of variable spines. In the female genitalia the papillae anales are broad; the sterigma has a weakly sclerotized lamella postvaginalis, aciculate, with lateral prominences directed forwards; and the corpus bursae is oval or elongate oval, with signa one, two, or no signa, and depressed patches.
Based on the character of the socii,
Diakonoff (1973)
divided
Sycacantha
into two species-groups: the
S. thermographa
group and the
S. inodes
group. However, in some species the socii are intermediate between the two
types
(
Diakonoff 1973
;
Horak 2006
). Species of this study are not classified because in the new species
S. camarata
the socii are intermediate.
Twenty-five full-length barcodes (658bp) representing 14 species of
Sycacantha
and
Phaecasiophora
are present in GenBank (accessed
30 June 2019
). In the present study, full-length barcodes of 18 exemplar specimens belonging to 14 species (
Table 1
) of
Sycacantha
and
Phaecasiophora
from
China
were successfully sequenced. A NJ tree (
Fig. 1
) based on the above 43 COI gene sequenes was constructed. The barcode sequences in the NJ tree form two distinctive clusters, a
Sycacantha
clade and a
Phaecasiophora
clade.
Phaecasiophora diserta
was embedded within
Sycacantha
and
S. obtundana
fell into
Phaecasiophora
. Although the clades were only weakly supported, the molecular data are consistent with features of the genitalia (the diagnosis will be mentioned later in this article). Thus, we proposed two new combinations. In the
Sycacantha
clade, COI sequences formed three clusters: the first comprised of four species (i.e.,
S. camarata
sp. nov.
,
S. typicusivalva
sp. nov.
,
S. diserta
comb. nov.
and
S. inopinata
), the second of three species (i.e.,
S. decursiva
sp. nov.
,
S. catharia
and
S. complicitana
); and the third of one species (i.e.,
S. inodes
). This result does not agree with the species-groups proposed by Diaknoff (1973). To reveal the relationships among the species and establish species-groups, further studies are needed with more extensive taxon sampling.
The genetic distances within
Sycacantha
are given in
Table 2
. Intraspecific divergence ranged from 0 to 1.7% among the nine species (
S. catharia
,
S. typicusivalva
sp. nov.
,
Sycacantha
sp. B,
S. sphaerocosmana
,
S. castanicolor
,
S. atactodes
,
S. placida
,
Sycacantha
sp. A, and
S. exedra
), and the interspecific divergence among the 19 species ranged from 0 to 11.6%. In
Lepidoptera
, barcode divergence of approximately 2% is generally congruent with morphology-based species-level identifications (
Hajibabaei
et al
. 2006
;
Zahiri
et al
. 2014
). We found the genetic divergence among specimens of
Sycacantha
sp. B,
S. sphaerocosmana
, and
S. castanicolor
to be less than 2%, ranging from 0 to 1.7%; whereas the genetic divergence among these specimens and other species is more than 4%. So we suspect that
Sycacantha
sp. B,
S. sphaerocosmana
, and
S. castanicolor
might be the same species.