A note on Gigantometopus Schwartz and Schuh (Heteroptera: Miridae: Isometopinae) with the description of a new species from Borneo.
Key words: Gigantometopus, Isometopinae, Heteroptera, Miridae.
Gigantometopus rossi was described by Schwartz and Schuh (1990) as a new genus and new species based on a single female from Sumatra. The large size of the specimen was unusual within the range known for all previously described isometopines and has since then been regarded a unique feature that has been used for identification. I had the opportunity to study a collection of Isometopinae from South East Asia that includes a new species of Gigantometopus and the examination of which suggests the large size of G. rossi may be unique for the species but not for the genus. The new species is hereby described and the limits of Gigantometopus are redefined.
All measurements are in millimeters unless where proportions are used. The type specimen is deposited in the Natural History Museum, London, designated as BMNH.
Gigantometopus schuhi, new species
HOLOTYPE: Male: BORNEO: Brunei: Bukit Sulang nr. Lamunin. 20.VIII-10.IX.1982, Insecticide fogging on Shorea maerocarpa N. E. Stork (BMNH).
DESCRIPTION: Male: Length 3.28. Maximum width across hemelytra 1.44. Head width across vertex 0.41; dorsal length 0.27; facial width 0.73; facial length 1.06. Anterior inter-ocular space 0.20; posterior space 0.60; minimum frontal space 0.12. Dorsal width of eye 0.13; maximum width 0.36; height 0.53. Height of gena 0.32; height of lorum 0.26. Ocellus width 0.05; interocellar space 0.10. Rostrum 1.84. Antennae I 0.14; II 0.91; III 0.93; IV 0.20. Maximum width of pronotum 1.44; median length 0.60. Scutellum length 0.64; width 0.69. Cuneus length 0.53; width 0.31.
Head: from above rather broadly reclined over anterior pronotal region, somewhat kidney-shaped in outline (Fig. 1A), about half as long as pronotum; frontal area more or less conical with bucculae prominently projecting snout-like (Fig. 1B), about 0.68x as broad as high. Vertex impunctate, only moderately convex, reddish. Frons similarly evenly convex, distinctly rugose punctuate; ivory to whitish ochraceous with narrow basal band plus large apical blotch reddish. Gena about 0.68x as high as eye; shallowly excavated proximally, more deeply so distally forming pocket-like depression beneath antennophore. Eyes large, reddish, distinctly separated (0.12 apart) frontally and behind vertex; strongly emarginate near ocelli and recurved to produce rather deep concavity behind vertex; sparsely obscurely hairy. Ocelli large, grayish translucent and somewhat appressed, about twice width of each apart. Rostrum with segment I deep red; apical band on IV, rather discrete spots towards base and apex on dorsal surface of III, darkened; otherwise pale to whitish and shortly erectly hairy, extending as far back as sixth abdominal sternite. Antennal segment I dark brown with fine reddish markings, pallid on extremities, half as thick as long. II largely dark brown, somewhat paler at base; more or less cylindrical and about 0.71 x as thick as I; broadly recurved and dense with erect hairs equal or subequal to segment thickness. III and IV darkened, somewhat striated and together appearing whip-like; dense with semi-erect hairs slightly longer that segment thickness. Thorax: Pronotum subcampanulate, about 2.19x as broad as long; disk strongly convex, inclined forwards, densely transversely rugose punctuate; lateral margin finely explanate, pale hyaline with reddish extremity; posterior margin sinuately convex to weakly bisinuate. Disk largely reddish-brown to dark-red, rather broad median area plus posterolateral angles somewhat paler. Mesoscutum and scutellum strongly tumid, largely reddish with tip of scutellum whitish; both punctuate, scutellum more coarsely so and transversely rugose. Hemelytra: largely dark golden to reddish-brown; radial vein, somewhat crescentic macula on disk of corium, sub-basal and sub-apical bands on clavus plus claval suture, all pale to whitish. Embolium with broad sub-apical band dark reddish-brown, otherwise whitish; cuneus reddish with basal mesal angle whitish. Corium and clavus thickset with pit-like punctures, embolium and cuneus impunctate. Membrane glabrous, distinctly biareolate; hyaline with veins contrasting reddish. Dorsum: generally shiny, densely pubescent with semi-reclining to semi-erect or erect golden hairs; those on corium somewhat darker. Venter: generally reddish to dark-reddish; pale to whitish on prosternum, extensive areas on propleura and abdominal sternites 3-7; mostly dense with semi-erect to erect golden yellow hairs. Prostemal xyphus weakly conically produced. Pleura coarsely punctuate, abdominal sternites 2-4 more finely so laterally. Legs." Fore and mid coxae largely whitish with variable proportions on ental surface reddish; hind coxae largely reddish-brown with whitish extremities. Remainder of foreleg with apical three-quarters of tibia, broad dorsal and ventral streaks plus some irregular patches on femur, pale hyaline to whitish; otherwise dark-reddish. Other units of mid and hind legs missing. GENITALIA: Fig. 2.
ETYMOLOGY: The new species is named in honor of Dr. Randall T. Schuh to mark his 70th birthday, his retirement, the fruitful professional relationship we have had over the last four decades and his outstanding contribution to the systematics of the Miridae in particular and the Heteroptera in general.
REMARKS: The description of Gigantometopus was based on a single female specimen that was quite unique for its large size of 6.98 mm that was previously unknown among all Isometopinae. The large size, however, seems peculiar to the nominotypic species G. rossi Schwartz and Schuh, and not of the genus, as can be seen in the much smaller size of the new species, G. schuhi now being described. The genus is characterized by the strongly vertical head with the anterior third or so projected upwards and weakly to distinctly deflexed over anterior pronotal margin. The gena is high and weakly to distinctly excavate with the antennophore located at its apex, far removed from the ventral eye margin. The lorum is elongate and distinctly excavate, forming together with the gena striking lateral concavity beneath the eye. The juga and tylus have prominent lateral carinae that form a striking V-shaped impression on the dorsal surface of the head. The pronotum is subcampanulate or weakly trapeziform with the disk strongly tumid and inclined forwards; and the calli are either prominently raised and confluent with rather large median fossa posteriorly or hardly evident but with the median fossa distinct. The scutellum is broader than long with the disk strongly tumid, and either weakly to distinctly heart-shaped or distinctly humped. Hemelytra commissure is much reduced, less than half as long as scutellum. The legs have 3-segmented tarsi, and a high femoral trichobothrial number, ranging from 5 mesofemoral to 5-6 metafemoral, all with distinct sunken bothria and compact trichomae. The pretarsi are devoid of preapical teeth. The distinctly elongate head, the scutellum broader than long in addition to forming a distinct commissure, the high number of femoral trichobothria with distinct sunken bothria and compact trichomae are features that place the genus in the Myiommini where it is very close to Isometopidea Poppius. It shares with the latter genus some of the general features of the head, the femoral trichobothrial number and pattern, and the structure of the pronotum, especially the presence of the median fossa. The head in Isometopidea is, however, much less elongate, the hemelytra commissure is usually much more than half as long as the scutellum, and in particular the antennophore is located at the base of the gena very close to, or abutting directly on the ventral eye margin. I have examined a female specimen from S. India deposited in the USNM collection (ref. USNM 2060278), which was identified as Gigantometopus prob. rossi. It however differs materially in some respects from G. rossi: the length for example being 5.67 mm while the rostrum is much longer, reaching as far back as the sixth abdominal sternite. This again suggests that Gigantometopus spp. manifests considerable size variations.
I am grateful to Dr. T. J. Henry of the Systematic Entomology Laboratory, ARS, USDA, c/o National Museum of Natural History (USNM), Smithsonian, Washington, DC, for the loan of the specimen from S. India.
Schwartz, M. D. and R. T. Schuh. 1990. The world's largest isometopine, Gigantometopus rossi, new genus and new species (Heteroptera: Miridae). Journal New York Entomological Society, 98(1): 9-13.
A. E. AKINGBOHUNGBE
Department of Crop Production and Protection, Obafemi Awolowo University, Ile-Ife 220005, Osun State, NIGERIA, email: email@example.com
Please note: Illustration(s) are not available due to copyright restrictions.
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|Date:||Jan 1, 2012|
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