Three new species of Rasahus, with clarifications on the identities of three other Neotropical corsairs (Heteroptera: Reduviidae: Peiratinae)
Author
Swanson, Daniel R.
text
Zootaxa
2018
2018-09-06
4471
3
446
472
journal article
29468
10.11646/zootaxa.4471.3.2
99ca680a-4cc1-42d0-82e8-e686851d3f0c
1175-5326
1439906
3E6513AE-948D-4474-97CA-389AE05F9931
Rasahus abolitus
sp. nov.
(
Figs. 3
,
10B
,
11C
)
Diagnosis
: Easily separated from all other species of
Rasahus
by the combination of small size (male less than
12 mm
) and the obsolete pronotal sulci and granules. The external genitalia of the male also are unique in possessing the combination of a strongly-bent, apically-tapering median process of the pygophore.
Coloration
: Blackish, except apical spine of scutellum, apical interior of clavus from scutellar spine to apex, adjacent part of corium from base to apex of clavus, three spots on hemelytral membrane (ovoidal spot near base, narrow arcuate spot near apex of corium, and forked spot at apex), anterior half of connexiva (dorsally and ventrally, with adjacent part of ventrite), apex of coxae, base of metafemur, base of all tibiae, and meso- and metatarsi whitish. Incisures of antennal segments (plus, base of scape), protarsi, and fossula spongiosa brownish.
Structure
: Anteocular region covered on all surfaces with short silvery pile, laterally with few long dark setae. Interocular region with width subequal to width of eye, with three setae in triangle and silvery pile dorsally (less so than anteocular but possibly abraided). Postocular region with short longitudinal sulcus reaching cephalad from transverse sulcus. Neck dorsally glabrous, laterally and ventrally with short pile.
Antennae: as per description under
Rasahus
.
Eyes in lateral view surpassing dorsal margin and nearly reaching ventral margin.
Ocelli large, somewhat raised, separated from each other by width of one ocellus, separated from eye by less than width of one ocellus.
Rostrum: as per description under
Rasahus
.
Pronotum: Anterior pronotal lobe with sulci essentially obliterated, short and long setae in remains of sulci, glabrous inbetween, disc unarmed, deep sulcus on midline in front of transverse suture that extends cephalad to middle of lobe. Posterior pronotal lobe smooth, without wrinkles or sulci, pilose along lateral and posterior margins.
Scutellum mostly obscured by pin, apex prolonged in dorsally-setose spine.
Pleura: Propleuron smooth. Metapleuron slightly transversely wrinkled, glabrous, metapleural sulcus narrow between carinae.
Sterna: Metasternum medially obscured by pin, possibly carinate midlongitudinally.
Hemelytra slightly but distinctly exceeding abdominal apex, veins of corium bearing semi-erect setae.
Forelegs: Profemur with ventral setae arranged in two rows. Protibial fossula spongiosa long, greater than halflength of tibia.
Middle legs: Tibia generally more pilose (more densely so ventrally) and with fewer distinct dorsal setae, mesotibial fossula spongiosa relatively shorter, about half-length of tibia. All else as fore legs.
Hind legs: as per description under
Rasahus
.
Abdomen connexiva with long thin seta at posterolateral angle, sutures poorly indicated. Apex of seventh ventrite strongly pilose.
Male genitalia: Eighth ventrite extended caudad as median triangular spine. Pygophore sparsely pilose, posterior margin concave between median process and base of parameres, median apical process tall, strongly sinuate (left margin strongly curved, right margin weakly so), broad and bent sinistral in basal half, curving dextral in apical half, apically tapering to acuminate point. Parameres large, asymmetrical, both spade-shaped, more pilose than pygophore, especially near apex, left paramere larger, with attenuated, mesally-bent, somewhat flattened apex, right paramere slightly broader with non-attenuated tectiform apex. Aedeagus not examined.
Female: unknown.
Measurements (in mm): total length (apex of head to apex of hemelytra): 10.2; head length: 1.7; head width (across eyes): 1.2; anteocular length: 0.7; postocular length: 0.3; neck length: 0.3; scape length: 0.8; pedicel length: 2.2; basiflagellum length: 1.8; distiflagellum length: 2.3; antennal segment ratio: 1.0: 2.75: 2.25: 2.9; eye length: 0.7; eye width: 0.4; rostral segment 1 length: 0.6; rostral segment 2 length: 1.0; rostral segment 3 length: 0.6; rostral segment ratio: 1.0: 1.67: 1.0; prothorax length: 2.4; prothorax width (across humeri): 2.5; anterior pronotal lobe length: 1.7; posterior pronotal lobe length: 0.7; scutellum length: 1.2; scutellum width (at base): 0.9; hemelytra length: 8.1; procoxa length: 1.6; protrochanter length: 0.6; profemur length: 2.7; protibia length: 2.5; protibial fossula spongiosa length: 2.0; protarsi length: 0.6; protarsal segment ratio: 1.0: 1.6: 1.6; mesocoxa length: 0.7; mesotrochanter length: 0.6; mesofemur length: 2.9; mesotibia length: 2.4; mesotibial fossula spongiosa length: 1.5; mesotarsi length: 1.1; mesotarsal segment ratio: 1.0: 2.1: 2.1; metacoxa length: 0.8; metatrochanter length: 0.7; metafemur length: 4.4; metatibia length: 5.0; metatarsi length: 1.9; metatarsal segment ratio: 1.0: 2.5: 2.0; abdomen length: 5.7; abdomen (widest) width: 2.7; pygophore length: 1.4; pygophore width (across widest point): 1.1.
Material examined
:
FRENCH GUIANA
: Kaw Mountains,
2 km
N. Route D6, MV light,
4°33.91’N
,
52°9.38’W
,
22 December 2000
, V. R. Block,
INHS
Insect Collection 780,124 [
1 male
,
holotype
] (
INHS
).
Distribution
: Known only from the
type
locality (
Fig. 4
).
Etymology
: The specific epithet is the Latin adjective
abolitus
, -
a
, -
um
, formed from the Latin verb
aboleo
‘to destroy, abolish, efface, annihilate, check the growth of, retard, decay’. This name was chosen to highlight the “effaced” sulci and granulations of the pronotal lobes.
Remarks
: The new species is very similar to
Rasahus scutellaris
auct. (nec
Fabricius, 1787
) (see below) in structure, color pattern, and small size (both
10–10.5 mm
in males). The color pattern also is similar to
R. sulcicollis
and to a lesser extent,
R. castaneus
, although their larger size precludes any of these species and their associated junior synonyms from being conspecific with R.
abolitus
sp. nov.
Morphologically, however,
R. abolitus
sp. nov.
and
R. scutellaris
auct. differ markedly in the structure of the pronotum. Coscarόn (1983a) noted in her redescription of
R. scutellaris
auct.: “[English transl.] Anterior [pronotal] lobe with granulations in the sulci and more or less well-marked basal depression where joins the lateral internal sulci.” In contrast, the anterior pronotal sulci of the new species are not at all well marked, being rather obsolescent. Granulations also appear to be essentially absent in the lateral internal sulci, but in the external and middle lateral sulci minor sculpturing is apparent under higher magnification (
Fig. 3C
). Coscarόn (1983a) also noted of
R. scutellaris
auct.: “[English transl.] Posterior [pronotal] lobe with granulation, rugosities, and hairs.”, and the posterior pronotal lobe of the new species is very smooth, lacking any granulation (ignoring microsculpture). The anteocular part of the head also is a slightly longer, composing a larger proportion of the overall head length than in
R. scutellaris
auct. Two other species, i.e.,
R. albomaculatus
and
R. surinamensis
, also lack granulations and well-defined sulci, but each possesses more extensive pale patterning on the hemelytra and is much larger (
21–25 mm
in
R. albomaculatus
and
16–18 mm
in
R. surinamensis
). Based on Coscarόn’s (1983a) plates, the genitalia closely resembles
R. scutellaris
auct., although
R. abolitus
sp. nov.
might differ in possessing a more acuminated apex of the median process (
Fig. 5D
) and a less attenuated left paramere (
Fig. 5E, F
).
As mentioned, the color pattern is very similar to
R. scutellaris
auct. In addition to generally sharing the same pale maculations, both species appear to be distinctive in their bicolorous scutellum: black with a whitish spine. However, a few differences exist. First, the claval stripe does not extend beyond the base of the scutellar spine in
R. abolitus
sp. nov.
, occupying approximately the apical third of the clavus, whereas in
R. scutellaris
auct. the claval stripe extends well beyond the base of the scutellar spine, occupying at least the apical half of the clavus. Second, the oblique pale corial stripe adjacent to the clavus (paraclaval stripe) is essentially complete in
R. abolitus
sp. nov.
, whereas it is nearly interrupted near the base in
R. scutellaris
auct. Third, a pale marginal stripe connects the paraclaval stripe to the central corial spot and continues along the posterior margin of the hemelytra in
R. abolitus
sp. nov.
; yet, this pale marginal stripe appears to be missing or obsolete in
R. scutellaris
auct. Fourth, the connexiva are pale in the basal half in
R. abolitus
sp. nov.
, rather than in the basal two-thirds in
R. scutellaris
auct. Finally, the apical pale spot of the membrane appears to follow the two apical veins, forming an inverted “Y”, in
R. abolitus
sp. nov.
, whereas the spot appears as a regular oval, enveloping the area between the two apical veins, in
R. scutellaris
auct. It is recognized that some of these color characters might be shown to vary intraspecifically in one or both species, as more specimens are examined.
Two other species of
Rasahus
were taken syntopically with
R. abolitus
sp. nov.
: a single adult male of
R. sulcicollis
(INHS Insect Collection 780,186) and a single adult female of
R. castaneus
(
Fig. 6A
). The two specimens bear an identical locality label to the holotype of
R. abolitus
sp. nov.
and were determined by the author. The latter specimen represents the first record of
R. castaneus
from French Guiana.
The identity of
Reduvius scutellaris
Fabricius, 1787
.
In order to confirm that
R. abolitus
sp. nov.
was not conspecific with
R. scutellaris
, images of the
holotype
of
Reduvius scutellaris
from
ZMUC
were studied. The species was described from “Cajennae” [=Cayenne,
French Guiana
] by
Fabricius (1787)
, and
Stål (1868)
later reported that the single
type
specimen was greatly damaged, with only portions of the head, thorax, scutellum, clavus, [hemelytral] membrane, and [hind] wings remaining. Receiving these images (
Fig. 7
) confirmed this highly-damaged status. However, the images also revealed that
Rasahus scutellaris
auct. (nec
Fabricius, 1787
) is not the same species as
Reduvius scutellaris
Fabricius, 1787
. Coscarόn (1983a) apparently had not studied the
type
of
Reduvius scutellaris
, nor had she examined material of this species from
French Guiana
.
FIGURE 3.
Rasahus abolitus
sp. nov.
, adult male (holotype): (A) dorsal habitus; (B) lateral habitus; (C) pronotum, dorsal view; (D) pygophore, caudal view; (E) labels. Scale bar = 2 mm.
FIGURE 4.
Map indicating type locality of
Rasahus nesiotes
sp. nov.
,
R. deliquus
sp. nov.
, and
R. abolitus
sp. nov.
It can be clearly seen that
Reduvius scutellaris
is a species of
Rasahus
in which a small pale spot is fully contained in the apical portion of the medial membranal cell, as opposed to
R. abolitus
sp. nov.
, the species referred to
Rasahus scutellaris
examined by
Champion (1899: pl. 13, fig. 9)
, and the species referred to
Rasahus scutellaris
figured by Coscarόn (1983a: pl. 18, fig. A). Contrary to Coscarόn’s (1983a) redescription,
Stål (1868)
stated that the length of
Reduvius scutellaris
was
15 mm
. The true identity of
Reduvius scutellaris
, based on plates in the revision (i.e., Coscarόn 1983a), should be one of the following species:
R. amapaensis
,
R. arcitenens
,
R. arcuiger
, or
Rasahus rufiventris
(
Walker, 1873
)
, as Coscarόn (1983a) had examined the
type
of each. Of these,
R. arcitenens
and
R. arcuiger
have a strong pale postscutellar macula (not apparent in
holotype
of
R. scutellaris
) and a larger pale spot of the medial membranal cell. Similarly,
R. amapaensis
also possesses a postscutellar spot, although it is not as striking. Conversely,
R. rufiventris
(
Fig. 6B
) matches well the damaged
holotype
of
Reduvius scutellaris
in the lack of a distinct postscutellar spot, the shape of the arcuate spot of the cubital membranal cell, and the small spot of the medial membranal cell.
Thus,
Pirates rufiventris
Walker, 1873
is here considered to be a junior synonym of
Reduvius scutellaris
Fabricius, 1787
syn. nov.
Additional specimens from the
type
locality compared with the remains of Fabricius’ mutilated
type
material will be useful to corroborate this status.
The identity of
Pirates myrmecinus
Erichson, 1848
.
Given the confounded identity of
R. scutellaris
, images of the
holotype
of
Pirates myrmecinus
from
ZMHB
were also studied. This is the only junior synonym of
R. scutellaris
, which was established by
Stål (1868)
;
Cimex scutatus
Gmelin, 1788
is clearly a misspelling of Fabricius’ specific epithet, as Gmelin referred to Fabricius’ original description.
Like
R. scutellaris
, the
holotype
of
P. myrmecinus
(
Fig. 8
) is badly damaged. Despite this damage, some important morphological features are still visible, allowing the status of this taxon to be further clarified. Simultaneously under study by me were two complete specimens from
Belize
that share these conspicuous morphologies (see Remarks below) and agree well with the
holotype
in other general facies. Thus, the taxon
Pirates myrmecinus
Erichson, 1848
, is here resurrected as a valid species, transferred to
Rasahus
, and redescribed, based on the Belizean specimens: