New enigmatic species of the genus Pediobius (Hymenoptera, Eulophidae) from Afrotropics, with notes on related genera
Author
Gumovsky, Alex
text
Zootaxa
2018
2018-06-21
4438
2
201
236
journal article
29842
10.11646/zootaxa.4438.2.1
bef88811-0d50-4fd7-90c3-153cfaa6f0e8
1175-5326
1294718
688C9DA1-BE32-4FC6-B726-65CA36358473
Pediobius
Walker, 1846
(
Fig. 2
)
Microterus
SPinola, 1811: 151
–152. TyPe sPecies:
Diplolepis petiolatus
SPinola, by subsequent designation of Gahan & Fagan 1923: 89. Synonymized by Bouček 1965: 7. Regarded as
nomen oblitum
in favor of
Pediobius
walker
by Hansson 2002: 146.
Pediobius
walker, 1846
: 184 (as a subgenus of
Entedon
Dalman
). TyPe sPecies:
Entedon
(
Pediobius
)
imbreus
walker, by subsequent designation of Ashmead 1904: 344, 384.
Pleurotropis
Förster, 1856: 78
, 82. TyPe sPecies:
Pleurotropis isomerus
Förster
, by subsequent designation of Förster 1861: xxxvii. Synonymized by Ferrière 1953: 400.
Pediobomyia
Girault, 1913: 155
. TyPe sPecies (by original designation):
Pediobomyia darwini
Girault.
Syn.
n.
Rhynchentedon
Girault, 1919: 166
. TyPe sPecies (by original designation):
Rhynchentedon maximum
Girault.
Syn.
n.
For full synonymy and diagnoses see Hansson (2002), Hansson & Nishida (2002), Cao
et al
. (2016).
Pediobius
is rather species-rich and morphologically diverse, and the species described below expand the concepts of morphological diversity within the genus. If all data is combined, the genus may be diagnosed as follows (
Fig. 2
): body dark, black or with metallic tint (
Fig. 2A
); head with complete frontal sulcus, more or less flat (most species,
Fig. 2D
) or largely smooth, convex (
afroteres
group,
Figs 9B–D
,
10A, C, D
); lower face slightly (most species,
Fig. 2D, F
) or considerably narrowed (groups
askari
:
Figs 12C
,
13A, C, D
,
14E, F
;
afroteres
:
Figs 9B–D
,
10A, C, D
;
maximus
:
Fig. 3B
,
darwini
:
Fig. 3D, E
); pronotal collar marked by a weak or strong carina (
Fig. 2B
); propleurae widely curved over lateral panel of pronotum (
Fig. 2B
, pl1/f); mesoscutum without a median groove, with notauli marked at least by depressions (often traceable as deep marginated foveae); mesoscutellum mostly without median groove, lightly or coarsely reticulated, occasionally with lateral groves (
P. alcaeus
Walker
,
P. bisulcatus
Cao & Zhu
); mesosternum with narrowly extended anterior border slightly overlapping posterior border of prepectus (
Fig. 2B
, eps2/p); transepimeral sulcus present, grooved, weakly or strongly curved (
Fig. 2B
, tps); metapleuron with a tooth-like protrusion; propodeum with lateral plicae and small anterior foveae (
Figs 2C, E
,
18
); median area of propodeum with two carinae diverging posteriorly (most species,
Fig. 2C, E
), which may be modified as a raised keel (
alcaeus
species group) or narrow submedian strip (
darwini
group, see below); posterior part of propodeum elongate in varying degrees and often forming a delimited area, ‘nucha’ (
Figs 2C, E
,
3C
); metasomal petiole distinct, robust and sculptured, often with raised upper edges (
Figs 2C, E
,
3C
,
18
).
Hosts and biology.
The species of the genus are characterized by conceivably the widest host spectrum among
Entedoninae
: the reliable records range from larvae and pupae of Lepidoptera, Diptera and Coleoptera to larvae of thrips and egg sacks of spiders; hyperparasitoids are also common among species of the genus (Bouček 1965; Noyes 2017). Ironically, the data on immature stages are limited for such a biologically diverse genus. The available records suggest that
Pediobius
species are endoparasitoids with three larval instars (e.g., Bledsoe
et al
. 1983).
Revisions.
The first comparative revision of
Pediobius
was provided by Bouček (1965) for its European species; which is still mostly up to date half a century after its publication, apart from a few nomenclatural changes. The Nearctic species were reviewed by Peck (1985) and the species occurring in the Japanese islands were keyed by Kamijo (1986). These reviews remain the main inventories for these regions. The Australasian species were listed and reviewed by Bouček (1988), and later reviewed by C. Burwell in his PhD thesis (Burwell 1995, unpubl.). The most recent comparative reviews are the revisions of Neotropical species by Hansson (2002) and of the Chinese species by Cao
et al
. (2017). The species from Indomalayan (
Oriental
) realm were reviewed by Kerrich (1973) in his revision of the tropical and subtropical species of this genus. The Afrotropical species were very selectively reviewed and many hitherto described species as well as major part of museum materials were omitted in that same article. So, the Afrotropical fauna remains one of the most challenging parts of the species diversity of the genus.
Comparative remarks.
Pediobius
Walker
is the core genus of its genus complex, which was proposed to include also
Rhynchentedon
Girault
,
Pediobomyia
Girault
,
Myrmokata
Bouček
and
Microdonophagus
Schauff (Gumovsky 2001)
. The complex was characterized (Gumovsky 2001, 2003) by the wide and robust propleural flange (bending to anterior margin of the pronotal panel,
Fig. 2B
, pl1/f), the anterior edge of mesosternum being narrowly extended and overlapping the prepectus (
Fig. 2B
, eps2/p), the lateral metapleural callus toothed, the metasomal petiole wide, robust, the propodeum with submedian foveae and more or less developed submedian propodeal carinae (
Figs 2C, E
,
3C
,
4E
). Hansson
et al
. (2011) suggested sister-group relationships between the genera
Horismenus
and
Microdonophagus
, which were supported by the sculpture of propodeum in the newly described species of the latter. The close relationships between
Pediobius
,
Rhynchentedon
and
Pediobomyia
were confirmed by Burks
et al
. (2011); however, the hierarchy of these relationships was not established due to disagreement of the phylogenetic patterns resultant from different analyses.
Rhynchentedon
,
Pediobomyia
and
Myrmokata
were also characterized by the narrowed lower face resembling the species of
Pediobius
described below. The wide range of the head shape and sculpture, as well as the variety of other characters (e.g. the sculpture of dorsum) in the species described below in the
marjoriae
,
afroteres
and
askari
groups, suggest reconsideration of the status of some genera of the
Pediobius
complex.
The genus
Rhynchentedon
was described by Girault (1919) and then reviewed by Bouček (1988) and Gumovsky (2001, 2004). The genus is characterized by the narrowed and elongate lower face with concave genae, the reduced mandibles, wide propleural flange, densely setose axilla, transepimeral sulcus continued into a dropshaped fovea, and the propodeum with spiracles situated in depressions and with diverging submedian carinae (
Fig. 3A–C
; Gumovsky 2001). In general, apart from the narrowed lower face and reduced mandibles,
Rhynchentedon
species resemble coarser sculptured and more setose representatives of
Pediobius
. The concave genae covered with dense setae may be considered a distinctive feature of
Rhynchentedon
(
Fig. 3B
). However, the presence of the very weakly setose genae in
R
.
narendrani
Gumovsky
hampers the diagnostic value of this character (Gumovsky 2004). The excessive setation, which is present in places in
R. maximus
Girault
and
R. achterbergi
Gumovsky
, is shared by some Afrotropical
Pediobius
species, namely
P. setigerus
Kerrich
and
P. multisetis
Bouček. The
reduced mandibles lacking the cutting edge, are also present in some species of
Pediobius
, e.g.
P. derroni
Bouček
(
Fig. 2F
, md). Finally, different degrees of elongation of the face occur in species of
Pediobius
, as described below (
Fig. 17A–D
).
The genus
Pediobomyia
was erected by Girault (1913) for his species
P. darwini
Girault
described from Australia. The genus was briefly discussed by Bouček (1988) and Gumovsky (2001). Hansson (2002) updated its diagnosis for two newly described Neotropical species. Narendran
et al
. (2007) reviewed this genus based on materials from the Indomalayan (Oriental) realm and synonymized
Bomyiabius
Narendran
(described earlier: Narendran 2004) with
Pediobomyia
. If all concepts are combined, the genus may be diagnosed as a group of entedonines with the lower face narrowed ventrally towards a very small mouth opening, mandibles lacking the cutting edges, scrobal and frontal sulci short grooved (
Fig. 3D, E
), metascutellum with longitudinal carina at lateral margins, propodeum elongate with plicae converging towards petiolar foramen, submedian propodeal carinae diverging posteriorly or subparallel, and propodeal spiracle placed on an elevation, with long pliciform protrusion below it (Bouček 1988, Gumovsky 2001, Hansson 2002). Also, Hansson (2002) suggested that the pronotum is strongly reduced and hardly visible in dorsal view in the Neotropical species assigned to
Pediobomyia
. The genus has been considered as morphologically distinct, if its species were compared to the described species of
Pediobius
or
Rhynchentedon
(Gumovsky 2001)
. However, if the representatives of
Pediobomyia
are compared to the species of
afroteres
group of
Pediobius
(described below:
Figs 8–11
), the differences in head shape and propodeum appear gradual. Furthermore, the representatives of the
marjoriae
(
Figs 5–7
) and
askari
(
Figs 12–15
) groups which are also described below, demonstrate a range of character states being gradual between the
afroteres
group and the most other
Pediobius
species.
FIGURE 1.
Some localities Where collections Were made: A, B, semi-deciduous rainforest betWeen Yedi and Uesa villages (Ituri Province, DRC): A, habitat, B, collecting; C, disturbed area at MongbWalu mining camP (“behind the Titanic block”) (Ituri Province, DRC); D, E, Yangambi, research Plot 1 of COBIMFO Project (Orientale Province, DRC): border betWeen abandoned shamba and secondary forest; F, G, Palabora reserve (LimPoPo Province, South Africa): F, “Dolerite road” site, G, Molengraaf farm; H, I,
Tamarix
trees at “Madala site” (Gauteng Province, South Africa): H, in APril, I, in November, under Windy Weather bringing dust from nearby mines; J, K, areas near Agnes Mine, vicinities of Barberton (MPumalanga Province, South Africa); A, B, the tyPe locality of
P. nganga
; C–I, localities Where
P. afroteres
Was
collected (F, its tyPe locality); J, K, localities Where
P. askari
Was
collected (J, its tyPe locality).
FIGURE 2.
MorPhology of the sPecies of
Pediobius
: A,
P. arcuatus
Kerrich
, habitus of the female; B,
P. bruchicida
(Rondani)
(head and mesosoma, lateral vieW, SEM); C,
P. imbreus
walker (tyPe sPecies of
Pediobius
), ProPodeum, SEM; D–F,
P. derroni
Bouček
, SEM: D, face; E, ProPodeum; F, loWer face (md, mandible).
FIGURE 3.
A–C,
Pediobius
sPP.: A–C, formerly classified in
Rhynchentedon
, D–E, formerly classified in
Pediobomyia
. A,
P. achterbergi
(Malaysia)
; B–C,
P. maximus
(SingaPore)
: B, head in frontal vieW With mouth oPening and mandibles in inset; C, mesosoma and anterior Part of metasoma of the holotyPe (BMNH); D, E,
P
.
darwini
(Australia)
: D, head, mesosoma and anterior Part of metasoma in lateral vieW, E, loWer face and mandible in lateral vieW.
FIGURE 4.
Myrmokata diparoides
(DRC): A, B, head, mesosoma and anterior Part of metasoma: A, lateral vieW, B, dorsal vieW; C, head and anterior Part of mesosoma, vieWed under angle; D, face; E, Posterior Part of mesosoma, ProPodeum and anterior Part of metasoma With tiny scutellar seta arroWed in inset.
A direct comparison of the species of
Rhynchentedon
and
Pediobomyia
with the species of
Pediobius
mentioned above suggests the gradual nature of the characters used to distinguish them. So, notwithstanding their odd general appearance, the species which have been classified in
Rhynchentedon
and
Pediobomyia
(as well as the species described below) appear derived groups within speciose and diverse genus
Pediobius
. Therefore, morphological evidence suggests that keeping all these species in separate genera putatively renders
Pediobius
paraphyletic.
The close relationships of
Pediobius
with
Rhynchentedon
and
Pediobomyia
were demonstrated by Burks
et al
. (2011) using molecular markers. The genera were always closely related in all phylogenetic analyses provided by the authors, and at least in the Bayesian molecular-only results and in the combined morphological and molecular results,
Rhynchentedon
+
Pediobomyia
appeared as a derived node within
Pediobius
with high bootstrap support (Burks
et al
. 2011). So, based on original morphological data and in part on results of molecular research of other authors, the generic names
Rhynchentedon
Girault
and
Pediobomyia
Girault
are hereby considered junior synonyms of
Pediobius
Walker
(
syn. n.
). The following new combinations are resultant from this synonymy:
P. maximus
(Girault)
,
P. achterbergi
(Gumovsky)
,
P. narendrani
(Gumovsky)
,
P. brevicaulis
(Hansson)
,
P. canaliculatus
(Hansson)
and
P. darwini
(Girault)
(
comb. n.
).
Bomyiabius frontus
Narendran
,
Pediobomyia budaicus
Narendran
and
Pediobomyia lankicus
Narendran
, described from Indomalayan realm by Narendran (2004) and Narendran
et al
. (2007), were reported as differing from
Pediobomyia darwini
Girault
in rather superficial or misinterpreted characters. For instance,
P. darwini
was reported as differing from three other species listed above in having F2 shorter than pedicel and darker legs with metallic tint, and the three species differ chiefly by the relative length of F1. However, these characters appear variable within series collected in various regions, their dimensions (relative length of F1 and F2) depend on measurement points (including or excluding petiole of the funiculars) and the degree of collapse when specimens are dried. Based on available descriptions and the morphology of the studied materials from Australasian, Indomalayan and Afrotropical realms (partly listed in Gumovsky 2001), all three specific names mentioned above are proposed to be junior synonyms of
Pediobius darwini
(Girault)
(in its new combination,
Fig. 3D, E
) (
syn. n.
). The species that have been previously classified in
Rhynchentedon
and
Pediobomyia
are proposed to represent two species groups within
Pediobius
:
maximus
and
darwini
,
respectively.
Myrmokata
Bouček
was described as an aberrant ant-associated Afrotropical entedonine genus for
M. diparoides
Bouček
from
Cameroon
(Bouček 1972). The material of
M. diparoides
from RMCA (
♀
, “Coll. Mus.
Congo
, Basoko, Yawinawina,
VIII.1948
, P.I.G. Benoit”,
Fig. 4
) expands distribution range of this species to
DRC
(
new record
).
Myrmokata
was characterized by the considerable reduction of pubescence on the dorsum of mesosoma, reduced number of setae on subcosta of submarginal vein (to one seta only), first gastral (second metasomal) segment with raised edges, unusually short tarsi, short frontal sulcus, and weak sexual dimorphism, including antennae (
Fig. 4
, here; Bouček 1972). Although it was described as having the dorsum of mesosoma without setae, a pair of very short setae is situated near the posterior edge of the mesoscutellum (
Fig. 4E
, inset). The propodeum characters were not mentioned among the diagnostic features of the genus; however, it was mentioned that the propodeum is “distinctly constricted to a nucha” and with a “vestigial median carina”. The actual morphology of
M. diparoides
suggests that the median area of propodeum is indeed bearing a median strip delimited laterally by fine carinae (
Fig. 4E
). Another interesting character of this genus is the elongate lower face with long genae (
Fig. 4D
) resembling to some extent the face of the
Pediobius
species described below. One of them,
P. marjoriae
, is also associated with ants, similarly to
M. diparoides
. The general habitus, the wide propleural flanges and the prepectus overlapped by mesosternal projection suggest the similarity of
Myrmokata
with
Pediobius
, whereas the other diagnostic characters of the genus may be secondary modifications associated with its parasitism in ants. However, the wide propleural flanges and prepectus overlapped by mesosternal projection are characteristics shared with the genera
Horismenus
and
Microdonophagus
, and the males of the latter demonstrate numerous morphological reductions associated with life in ant nests. Possible relationships between
Myrmokata
and
Horismenus
were also suggested by Bouček (1972). So, the status of
Myrmokata
may remain unrevised until more data (for instance, molecular) are available.