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
Mansonia
(
Mansonioides
)
africana
Theobald
subspecies
africana
(
Theobald, 1901c
)
—original combination:
Panoplites africanus
. Distribution:
Angola
,
Benin
,
Botswana
,
Burkina Faso
,
Cameroon
,
Central African Republic
,
Côte d’Ivoire
,
Democratic Republic of the Congo
,
Equatorial Guinea
,
Ethiopia
,
Gabon
,
Ghana
,
Kenya
,
Liberia
,
Mali
,
Mozambique
,
Nigeria
,
Senegal
,
Sierra Leone
,
South Africa
,
South Sudan
,
Sudan
,
Tanzania
,
Gambia
,
Uganda
,
Zambia
(
Wilkerson
et al
. 2021
).
subspecies
nigerrima
Theobald, 1910
—original combination:
Mansonia nigerrima
(varietal status by
Edwards 1913a
; subspecific status by
Harbach & Howard 2007
). Distribution:
Senegal
,
Tanzania
,
Uganda
(
Wilkerson
et al
. 2021
).
Mansonia africana
is a well-known African species of the subgenus
Mansonioides
Theobald, 1907
; however, like most Afrotropical species of
Culicidae
, the larval and pupal stages of this species have not been fully described and illustrated. Descriptions of the adults of subspecies
nigerrima
lack illustrations and are brief and superficial, and the immature stages are unknown.
Theobald (1901c)
described
Mn. africana
(as
Panoplites africanus
) from “Quite a number of this species in the collection from Asaba”, a city in southern
Nigeria
. He added that “The specimens collected at Asaba differ in no respects from those in the other parts of West and Central Africa.” According to
Townsend (1990)
,
two syntypes
are present in the Natural History Museum, London—“
Malawi
:
2 female
[head only of 1, on slide],
Zomba
, Chiromo, Lower Shire.… This is one of the
syntypes
from ‘West and Central Africa’ referred to generally in the description and listed more fully in
Theobald (1901c: 188)
.” It is not clear to which of the
two females
this applies, but we assume it is not the one represented by the slide-mounted head. In either case, the localities listed by
Theobald (1901c)
for his (second) description of
Panoplites africanus
do not include Asaba [they include Chiromo, Fort Johnstone (now called
Mangochi
) and Lower Shire (Shire River) in former British Central Africa (present-day
Malawi
), and
Lagos
and Old Calabar (contemporary Duke Town) in
Nigeria
]. It is unfortunate that
Stone
et al
. (1959)
and
Knight & Stone (1977)
did not arrange Theobald’s early publications in strict chronological order.
Theobald (1901c)
[??/09/1901] predates
Theobald (1901c)
[
12/11/1901
] by two months; consequently, it seems that the specimens from Asada,
Nigeria
are non-extant and the two “
syntype
” females have no taxonomic status.
Theobald (1910)
described
Mansonia nigerrima
based on a single female from Mpuma,
Uganda
(Mpuma, now known as Mpuma-Luga, is a city in the
Mukono District
, Central Region, located about
28 km
east of
Kampala
).
Edwards (1913a)
placed
Ma. major
Theobald, 1903a
and
Mn. nigerrima
in synonymy with
Mn. africana
(as
Mansonioides africanus
) but then, seemingly reluctantly, treated
nigerrima
as a variety, saying: “
M. nigerrima
may perhaps rank as a good variety; it is much darker than the
type
: the thorax is darker, with hardly a trace of pale markings; the dark scales of the wings are much more numerous than the light, and the white rings at the bases of the hind tarsal joints are much narrower than in typical
M. africanus
. The male genitalia, however, do not differ in any way. This form has up to the present only been found in
Uganda
.”
Edwards (1932a
,
1941
) was the only taxonomist post-Theobald (1901c, 1901d) to recognize and treat
nigerrima
as a separate form. Later workers,
Hopkins (1936
,
1952
),
da
Cunha
Ramos & Ribeiro (1975)
,
Service (1990)
,
Jupp (1996)
and
Becker
et al
. (2020)
, only recognized the nominotypical form, perhaps because they considered
nigerrima
to merely be a morphological variant. These authors were, of course, with the possible exception of Becker
et al
., unaware that
Harbach & Howard (2007)
had raised
nigerrima
to subspecific rank based on provisions of the
International Code of Zoological Nomenclature
: “Despite Edwards’ (1913a) apparent reluctance to treat
nigerrima
as a variety, implying that it should perhaps be regarded as an infrasubspecific entity, it is deemed to have subspecific rank because it was adopted (originally) as the valid name of a species before 1985 (Article 45.6.4.1).” In the absence of concrete morphological differentiation and evidence of geographical isolation, we believe that the action taken by Harbach & Howard, based merely on provisions of the
Code
, was ill-considered. Of course
nigerrima
could possibly be a separate species, but until this is conclusively proven, based on comparative morphological study of all life stages and molecular assessment, we believe it is prudent to consign
nigerrima
to synonymy:
nigerrima
Theobald, 1910
, junior subjective synonym of
Mansonia
(
Mansonioides
)
africana
(
Theobald, 1901c
)
. Consequently,
Mansonia nigerrima
should be removed from the species of
Mansonia
listed in the Encyclopedia of Life.
As indicated above, contrary to
Wilkerson
et al
. (2021)
,
Mn. major
Theobald, 1903a
was synonymized with
Mn. africana
by
Edwards (1913a)
, not
Edwards (1932a)
, who stated that “
M. major
was described from a flattened, but typical female specimen [of
Mansonioides africanus
].” There is no reason to doubt this synonymy, and it is retained, along with
Mn. nigerrima
, as a synonym of
Mn. africana
.