The insupportable validity of mosquito subspecies (Diptera: Culicidae) and their exclusion from culicid classification
Author
Harbach, Ralph E.
0000-0003-1384-6972
r.harbach@nhm.ac.uk
Author
Wilkerson, Richard C.
0000-0001-6366-1357
wilkersonr@si.edu
text
Zootaxa
2023
2023-06-15
5303
1
1
184
http://dx.doi.org/10.1094/PDIS-04-22-0755-PDN
journal article
53758
10.11646/zootaxa.5303.1.1
55cb0aa4-25b5-43fc-b545-54697a22b641
1175-5326
8043342
DE9C1F18-5CEE-4968-9991-075B977966FE
Aedes
(
Collessius
)
elsiae
(Barraud)
subspecies
elsiae
(
Barraud, 1923a
)
—original combination:
Finlaya elsiae
. Distribution:
Cambodia
,
India
,
Malaysia
,
Nepal
,
People’s Republic of China
,
Taiwan
,
Thailand
,
Vietnam
(
Wilkerson
et al
. 2021
).
subspecies
vicarius
Lien, 1968
—original combination:
Aedes
(
Finlaya
)
elsiae vicarius
. Distribution:
Taiwan
(
Lien 1968
).
The nominotypical subspecies was described from male and female cotypes (
Barraud 1923a
) and other conspecifics from Shillong,
Assam
,
India
. Using exuviae from the cotypes and additional specimens to document variation,
Barraud (1923c)
described the larva with illustrations of the siphon and antenna.
Barraud (1934)
then described in more detail the adults (both sexes) and larva, with illustrations of the larval head, thorax and siphon.
Darsie (2010)
described the pupa of
elsiae
(as a species of
Ochlerotatus
Lynch Arribálzaga, 1891a
) from sites in
Nepal
relatively close (about
400 km
) to the type locality of
elsiae
in northern
India
.
Townsend (1990)
reported
19 syntypes
of
elsiae
in the collection of the Natural History Museum, London, but not the cotypes or larval exuviae.
Subspecies
vicarius
was described and illustrated in all life stages, except the egg, from Chuchi, Chiai Hsien,
Taiwan
, but was also documented from many other localities in the original description. It is apparently found only on
Taiwan
. It and
elsiae
are similar in many respects in the adult and larval stages. In the larval stage, the two nominal forms have setae 1-M and 1-T very stout and borne on prominent tubercles, and seta 1-S stout and aciculate. The unusual character of these stout thoracic setae is also found in
Aedes
(
Collessius
)
shortti
(
Barraud, 1923a
)
and
Ae
. (
Col
.)
macfarlanei
(
Edwards, 1914
). The larval cuticle of subspecies
vicarius
is, however, densely covered with spicules, a significant difference from
elsiae
.
Lien (1968)
summarized the differences between
elsiae
and
vicarius
in the original description: “
The mosquito
[
vicarius
], in most respects, shows a close resemblance to
Aedes elsiae
and is therefore described here as a new subspecies of
Aedes elsiae
. It differs from
type
species chiefly as follows: The venter of adults mainly dark brown instead of ‘mainly yellowish’; a patch of broad dark scales sandwiched by two patches of broad white scales on upper and middle aspects of
ppn
[postpronotum] instead of ‘narrow yellow and broad white scales on lower border of
ppn
’; antennal hair [seta] 1-A of larva inserted at about basal third of shaft and bifid instead of ‘at about middle’ and ‘with 3–5 branches’; thoracic and abdominal integument densely spiculate. The male terminalia is [
sic
] almost indistinguishable from that of
type
species.” We instead judge these differences to clearly indicate separate species. We do not accept the reasoning that since the two forms are similar that they should be subspecies.
The pupal stage of
elsiae
was not available to
Lien (1968)
when he published a detailed illustration of the pupa of
vicarius
. The description and illustration of the pupa of
elsiae
by
Darsie (2010)
allowed direct comparison of the pupae of the two nominal forms.
Darsie (2010)
wrote: “From the illustration it can be separated from the subspecies
elsiae
pupa as follows: in
Oc
.
e
.
vicarius
seta 1-II has 4 branches and
Oc
.
e
.
elsiae
has 10–16 branches; seta 9-VII has 4 branches in the former and 8–10 branches in the latter.” We compared the illustrations of the two nominal forms and confirm the differences noted by Darsie. However, we also note many other obvious differences, such as nearly universal differences in the length and number of branches of setae (shorter and fewer in
vicarius
) and a very differently shaped paddle (~1.25 times longer than wide in
vicarius
; nearly round in
elsiae
). It is always possible that this is attributable to an undetected species complex, misidentification or a mix-up of specimens or illustrations, but the differences in the larval stage and adults remain to support our conclusions.
Given the significant morphological differences and the geographic isolation of subspecies
vicarius
, we hereby recognize its status as a species:
Aedes
(
Collessius
)
vicarius
Lien, 1968
.
Aedes vicarius
is currently listed as a species in the Encyclopedia of Life.
Aedes
(
Col
.)
elsiae
has one synonym:
Aedes
(
Finlaya
)
simulatus
Barraud, 1931
. It was described from a single female from
Assam
, Haflong, Cachar Hills,
India
and was listed as a synonym, without comment, in
Barraud (1934)
. There are no synonyms of
Ae.
(
Col
.)
vicarius
.