Xantholinus dvoraki Coiffait, 1956, the only valid species of the subgenus Meneidophallus Bordoni, 1999, with remarkably variable internal sac of aedeagus (Coleoptera, Staphylinidae)
Author
Gusarov, Vladimir I.
text
Zootaxa
2002
2002-02-11
21
1
11
journal article
10.5281/zenodo.4620282
f4ae5f19-1b63-4c0c-a145-56482c714b29
11755326
4620282
Xantholinus
(
Meneidophallus) dvoraki
Coiffait, 1956
(
Figs. 1–7
)
Xantholinus
(s.str.)
dvoraki
Coiffait, 1956a: 163
Xantholinus
(s.str.)
roubali
Coiffait, 1956b: 142
,
syn. nov.
Xantholinus
(s.str.)
dissimilis
Coiffait, 1956b: 143
,
syn. nov.
Xantholinus
(s.str.)
alaiensis
Coiffait, 1966a: 125
,
syn. nov.
Xantholinus
(s.str.)
schweigeri
Coiffait, 1966b: 22
,
syn. nov.
Xantholinus
(s.str.)
schweigeri
Coiffait, 1971: 431
Xantholinus
(
Meneidophallus
)
balaton
Bordoni, 1973a: 47
,
syn. nov.
Xantholinus
(
Meneidophallus
)
varhegyanus
Bordoni, 1973b: 152
,
syn. nov.
Xantholinus
(
Meneidophallus
)
lichtneckerti
Tóth, 1985: 173
Xantholinus
(
Meneidophallus
)
magyaricus
Tóth, 1985: 174
,
syn. nov.
Xantholinus
(
Meneidophallus
)
pseudobalaton
Tóth, 1985: 175
,
syn. nov.
Xantholinus dvoraki
: Lohse, 1987: 138
.
Xantholinus lichtneckerti
: Lohse, 1987: 138
(as synonym of
X. dvoraki
)
.
Xantholinus schweigeri
: Lohse, 1987: 138
.
Xantholinus magyaricus
: Lohse, 1987: 138
(as synonym of
X. schweigeri
Coiffait, 1971
)
Xantholinus
(
Meneidophallus
)
dvoraki
: Gusarov, 1998: 105
Xantholinus schweigeri
Coiffait, 1971
: Herman, 2001a: 32 (as synonym of
X. schweigeri
Coiffait, 1966
)
Type
material
Holotype
of
X. dissimilis
, (1Sb(1+1)M),
Slovakia
: Bystrica (MNHN);
holotype
of
X. roubali
, (1Sb(1+1)M),
Slovakia
: Bratislava (MNHN);
holotype
of
X. varhegyanus
, (1Sb1M),
Romania
: Varhegy (Zoppa) (CB).
Material additional to the above
types
Russia
: Belgorod reg.: (1Sb1M), Borisovka (D.Krasil’nikov)
1619.x.1988
; (1Sb1M), 2 (1Sb(1+1)M), ditto but
1316.x.1988
; (1Sb1M), (1Sb(1+1)M), ditto but
1013.x.1988
; (2Sb(1+1)M), ditto but (V.A.Krivokhatskiy)
6.iv.1985
; Voronezh reg.:
(1Sb(1+1)M), Voronezh (V.Kozlov)
15.v.1960
(all – DESPU); (1Sb(1+1)M),
25km
NNE Voronezh, Usmanskiy Bor (M.N.Tsurikov)
2.x.1992
; (1Sb(1+1)M), ditto but
23.x.1992
(all – CT); (1Sb(1+1)M), ditto but
21.iii.1995
; (2Sb(1+1)M), ditto but
5.iv.1995
; Samara reg.: (2Sb(1+1)M), Zhigulyovskiy Nature Reserve (Yu.P.Krasnobayev)
217.v.1988
; Rostov reg.: (2Sb(1+1)M), RostovnaDonu (E.A.Khachikov)
v.1992
; (1Sb(1+1)M), ditto but
29.viii.1976
(all – DESPU); 2 (2Sb(1+1)M), Kamensk, (E.A.Khachikov)
7.viii.1996
(DESPU, CK); (0Sb1M), 4 (1Sb(1+1)M), (2Sb(1+1)M), Shchepkinskiy Les (E.A.Khachikov)
15.ix.1991
(DESPU, CK); (2Sb(1+1)M), (2Sb1M), ditto but
10.ix.1992
(DESPU); KabardinoBalkarskaya Aut. Republic: 2 (1Sb(1+1)M), Nal’chik, B.Kizilovka (A.Kravets)
23.v.1987
;
Turkey
: (2Sb(1+2)M) W.
Anatolia
, Abant Gölü,
1450m
(G.Fagel),
v.1967
; 3 (1Sb2M, 1Sb(1+2)M, 2Sb(1+1)M) W.
Anatolia
, Abant Dagh,
14001550m
(G.Fagel),
v.1967
(all – IRSNB);
Kazakhstan
: (1Sb(1+1)M) Dzhambul (ZFMAK).
Diagnosis
Among other species of
Xantholinus
specimens of
X. dvoraki
can be easily recognized by the combination of: black head; dark brown pronotum, elytra and abdomen; reddish brown antennae, palpi and legs; head with transverse microsculpture, often erased in the center of the disc; pronotum without microsculpture or with weak transverse microsculpture near lateral margin; aedeagus with 15 isolated spines in the middle portion of internal sac (
Figs. 37
).
Discussion
In the subgenus
Meneidophallus
the internal sac includes the following structures (
Figs. 12
): two apical rows of spines (A1A2), the median group of isolated spines (M), the subbasal group of isolated spines (Sb), four basal rows of spines (B1B4) and the basal group of scales (L). Relative position of these structures refers to everted sac. When it is packed inside the aedeagus capsule the apical structures of the sac lie at the bottom of the aedeagus while the basal structures of the sac are located close to the aedeagus apex.
FIGURES 12.
Xantholinus dvoraki
Coiffait
(1 – Turkey, Abant Dagh; 2 – Russia, Rostovna Donu).
1 – aedeagus, dorsal view; 2 – partially everted internal sac of aedeagus. A1A2 – two apical rows of spines; B1B4 – four basal rows of spines; L – basal group of scales; M – median group of isolated spines; Sb – subbasal group of isolated spines. Scale
0.25 mm
(1),
0.4 mm
(2).
The basal group of scales (L), four basal (B1B4) and two apical (A1A2) rows of spines were present in all specimens that I examined. Coiffait (1956b) reported that in the
holotype
of
X. dissimilis
the apical rows of spines were entirely missing. However, the reexamination of the
holotype
demonstrated that both apical rows were in fact present. The genitalia preparation made by Coiffait is very pale, probably because of overexposure to KOH, and apparently Coiffait did not notice the spines of the apical rows.
FIGURES 37.
Internal sac of aedeagus of
Xantholinus dvoraki
Coiffait
(3, 5, 6 – Russia, Borisovka; 4, 7 – Russia, RostovnaDonu). Scale 0.4 mm.
The median and subbasal groups of isolated spines are subject to variation in
Meneidophallus
. The number of spines in these groups varies, and the spines within a group may be separate or close to each other (
Figs. 37
). In the latter case a pair of spines is enclosed in the shared pocket which is clearly visible when the sac is not everted (
Figs. 67
). In this paper I will use abbreviations to describe the number of spines in the median (M) and subbasal (Sb) groups. For example, the abbreviation 2Sb(1+1)M means that the sac has two juxtaposed spines (in the shared pocket) in the subbasal group and 2 separate spines in the median group.
It is worth mentioning that the characters of internal sac are often hard to observe and even harder to illustrate when the sac is packed inside the aedeagus capsule. It is easy to miss a spine if it is blocked by other structures. For example, in his description of
X. varhegyanus
Bordoni (1973b)
illustrates and describes the internal sac as 0Sb
1M.
However, the reexamination of the
holotype
demonstrated that the correct formula was 1Sb
1M.
Unfortunately, it is impossible to evert the internal sac of the specimens that have been preserved in alcohol or dried. To illustrate the spines of the median and subbasal groups it is more convenient to dissect the aedeagus and remove the internal sac, as has been done by Tóth (1985) and done in this paper (
Figs. 37
).
Traditionally, the specimens with different sets of median and subbasal spines were assigned to separate species. In fact, the number and relative position of these spines were the only reliable characters used to distinguish between the species described in
Meneidophallus
(
Table 1
).
TABLE 1.
Different types of internal sac traditionally assigned to separate species in the subgenus
Meneidophallus
.
Number of spines in the group
Species name Subbasal group of isolated spines (Sb) Median group of isolated spines (M) The examination of available material shows that the specimens with different
types
of internal sac occur in the same localities and often in the same samples. To illustrate this fact I compiled the data both from published records and the material that I examined (
Table 2
). Considering that the specimens with different
types
of internal sac occur in the same localities and do not differ in any other characters, I regard all these specimens as one and the same species with variable internal sac. Below I present the motives for the synonymy of each name in more details.
|
X. pseudobalaton
|
0 |
1+1 |
|
X. alaiensis
|
0 |
1+1+2 |
|
X. balaton
|
1 |
1 |
|
X. varhegyanus
|
1 |
1 |
|
X. roubali
|
1 |
1+1 |
|
X. dissimilis
|
1 |
1+1 |
|
X. schweigeri
|
1 |
2 |
|
X. dvoraki
|
1+1 |
2 |
|
X. magyaricus
|
2 |
1 |
|
X. lichtneckerti
|
2 |
1+1 |
I did not examine the
holotype
of
X. dvoraki
(
type
locality: felákovice,
Czech Republic
). According to the drawing by Coiffait (1956a: Fig. III) the
holotype
has internal sac of (1+1)Sb2M
type
. The original description of
X. dvoraki
agrees with the specimens examined by me (including the males from
Slovakia
) in all characters except the
type
of internal sac, which I consider to be extremely variable in this species.
The
holotype
of
X. roubali
examined by me does not differ externally from other specimens listed in the material and has internal sac of 1Sb(1+1)M
type
, which was found to cooccur with four other
types
of internal sac (
Table 2
).
TABLE 2.
Cooccurrence of different types of internal sac in the same locality (++, examined material; +, published data).
|
A
|
B
|
C
|
D
|
E
|
F
|
G
|
H
|
I
|
J
|
|
A
0Sb1M
|
|
++ |
++ |
++ |
|
B
0Sb(1+1)M
X. pseudobalaton
|
|
+ |
|
C
1Sb1M
X. balaton
X. varhegyanus
|
|
++ |
+ |
++ |
|
D
1Sb(1+1)M
X. roubali
X. dissimilis
|
++ |
++ |
|
++ |
++ |
|
E
1Sb2M
X. schweigeri
|
|
++ |
+ |
++ |
++ |
|
F
1Sb(1+2)M
|
++ |
|
++ |
++ |
|
G
(1+1)Sb2M
X. dvoraki
|
+ |
|
|
H
2Sb1M
X. magyaricus
|
++ |
++ |
+ |
|
++ |
|
I
2
Sb(1+1)M
X. lichtneckerti
|
++ |
+ |
++ |
++ |
++ |
++ |
++ |
|
++ |
|
J
2Sb(1+2)M
|
++ |
++ |
++ |
|
The
holotype
of
X. dissimilis
examined by me has internal sac of 1Sb(1+1)M
type
, the same as the
holotype
of
X. roubali
, and I could see no significant difference between the two in any other character. According to Coiffait (1956b:
Fig. 7
) the apical rows of spines in internal sac of the
holotype
of
X. dissimilis
were entirely missing. My reexamination of the
holotype
demonstrated that both apical rows were in fact present. The genitalia preparation made by Coiffait is very pale, probably because of overexposure to KOH, and apparently Coiffait did not notice the spines of the apical rows.
I did not examine the
holotype
of
X. alaiensis
(
type
locality: SakhiMardan,
Kyrgyzstan
), which has internal sac of 0Sb(1+1+2)M
type
according to the drawings by Coiffait (1966a:
Figs. 34
). The original description of
X. alaiensis
corresponds to the specimens examined by me (including the male from
Kazakhstan
(1Sb(1+1)M)) in all characters except the
type
of internal sac which I consider to be extremely variable in
Meneidophallus
.
I did not see the
holotype
of
X. schweigeri
Coiffait, 1966
b or
X. schweigeri
Coiffait, 1971
[These two names were synonymized by Herman (2001a) and probably have one and the same specimen as the
holotype
] (
type
locality: lake Abant,
Turkey
). According to the drawings (Coiffait 1966b:
Fig. 1
; Coiffait 1971:
Fig. 1
, A) both
holotypes
have internal sac of 1Sb2M
type
. Both descriptions published by Coiffait agree with the specimens listed in the material, including four males from near the
type
locality which have four different
types
of internal sac (1Sb2M is one of them).
I did not examine the
holotype
of
X. balaton
(
type
locality: Zalavár,
Hungary
) which has internal sac of 1Sb1M
type
(Bordoni 1973a:
Fig. 2
). The description of
X. balaton
corresponds to the specimens examined by me (including the males from
Slovakia
and
Romania
) in all important characters. Three different
types
of internal sac were found to cooccur with 1Sb1M
type
(
Table 2
).
The
holotype
of
X varhegyanus
examined by me has internal sac of 1Sb1M, and not 0Sb1M, as illustrated by Bordoni (1973b: Fig. B). In all important characters the
holotype
is similar to the specimens listed in the material.
I did not examine the
holotype
of
X. lichtneckerti
(
type
locality: Sukoró,
Hungary
) which has internal sac of 2Sb(1+1)M
type
according to the drawing by Tóth (1985:
Fig. 1
). The description of
X. lichtneckerti
corresponds to the specimens listed in the material (including the males from
Slovakia
and
Romania
) in all important characters. Lohse (1987) considered
X. lichtneckerti
to be synonymous with
X. dvoraki
. Eight other
types
of internal sac were found to cooccur with 2Sb(1+1)M
type
(
Table 2
).
I did not see the
holotype
of
X. magyaricus
(
type
locality: Sukoró,
Hungary
, the same as in
X. lichtneckerti
), which has internal sac of 2Sb1M
type
according to Tóth (1985:
Fig. 2
). The description of
X. magyaricus
agrees with the specimens listed in the material (including the males from
Slovakia
and
Romania
) in all important characters. Lohse (1987) considered
X. magyaricus
to be a synonym of
X. schweigeri
Coiffait, 1971
. Four different
types
of internal sac were found to cooccur with 2Sb1M
type
(
Table 2
).
I did not examine the
holotype
of
X. pseudobalaton
(
type
locality: Siófok,
Hungary
) which has internal sac of 0Sb(1+1)M
type
(Tóth, 1985:
Fig. 3
). The description of
X. pseudobalaton
fits the specimens examined by me (including the males from
Slovakia
and
Romania
).
Because the number of spines in the internal sac is the only major difference between the forms originally described as separate species of the subgenus
Meneidophallus
, I consider all these forms to be conspecific and place them in synonymy with
X. dvoraki
. I could not see any significant difference between the specimens from Central Europe,
Turkey
and Central Asia.
X. dvoraki
is a widespread WesternCentral Palaearctic species. The information on its distribution in the Eastern part of the range is fragmentary because the males of
X. dvoraki
seem to be active in spring and autumn, and rare in summer time, when most collections are made. It is not clear if the females of
X. dvoraki
are present through the summer, because it is hard to distinguish the females of
X. dvoraki
from the females of other widespread and common species, such as
X. linearis
(Olivier, 1795)
and
X. longiventris
Heer, 1839
. Special efforts to collect early and late in the season are needed to clarify the geographical distribution of
X. dvoraki
.
FIGURE 8.
Frequency distribution of different types of internal sac in examined material.
The possibility of variation in internal sac of
Xantholinus
has already been mentioned by Lohse (1987) who saw some specimens of
X. linearis
with one of the normal two big spines missing. Lohse believed that similar variability might occur in
Meneidophallus
. He assumed that
X. dvoraki
,
X. schweigeri
and
X. pseudobalaton
might be the forms of the same species, but he did not make the final decision since he did not have enough specimens available. I am not aware of any special study of the variability of internal sac in staphylinids, but such work has been done on some species of carabid genera
Harpalus
Latreille, 1802
and
Ophonus
Dejean, 1821 (Kataev 1995)
. The variation in internal sac of
X. linearis
and carabids differs from variation in
X. dvoraki
in one important respect. In the first two the abnormal forms are relatively rare (their frequency is about 26% in the five species of carabids studied by Kataev), while in
X. dvoraki
it is not even possible to tell what
is
normal (
Fig. 8
). The frequencies of the two most common forms are 49% and 26%. This is a very unusual example of high intraspecific variability of the internal sac. It seems reasonable to assume that in
X. dvoraki
the middle portion of the sac is not as important in copulation and is not controlled by selection pressure as tightly as the apical and basal portions.