Halorhynchus remii Chamorro & Steiner, 2022

Chamorro, Maria Lourdes & Steiner, Warren, 2022, A new species of Halorhynchus from Madagascar (Coleoptera, Curculionidae, Cossoninae, Onycholipini), ZooKeys 1100, pp. 103-116 : 103

Halorhynchus remii Chamorro & Steiner sp. nov.

Figs 1A-D , 2A , 3B

Material examined.

Holotype: USNMENT00896694 Madagascar: Prov. Toliara; Ifaty 23°09'S, 43°37'E, 18 September 1993 // under leaf litter beneath spreading plants on dry dunes; coll. W.E. Steiner, R. Andriamasimanana (USNM).

Diagnosis.

The new species strongly resembles the Western Australian species Halorhynchus caecus , but can be distinguished from it by the pronotum being wider 2/3 from the base, the shallower and relatively smaller pronotal punctation, the more acutely pointed apex (uncus) of the foretibiae, the hind tarsi in lateral view with setose, elongate, sclerotized tarsal extensions, and clawlessness.

Description.

Size: 2.0 mm. Reddish-brown, oval, shiny, with elongate stramineous lateral setae on body. Head: short, not basally constricted. Frons convex, foveola reduced. Eyes absent. Rostrum as long as wide (dorsal and lateral view), narrower than frons and head, widening apically, dorsally with weak longitudinal depression at base of rostrum; apex truncate. Scrobes short, reaching base of rostrum, directed ventrad, expanding proximally, shallow. Antennae short, located approximately one-third from base of rostrum; scape short, almost subequal to first funicular segment; funicle 5-segmented, segment 1 equal to 2 and 3 combined, segments 2-5 dorso-ventrally compressed, subequal size and shape; club short, elliptical, as long as segments 2-5 combined, shiny, appearing 1-segmented, apex with clump of medially directed elongate, stout, stramineous setae. Hypostomal tooth pronounced. Proventriculus not dissected. Thorax: Prothorax trapezoidal with rounded anterior and posterior angles, widest at basal third, narrowed anteriorly but not compressed or rimmed; punctation sparse, shallow, small. Scutellum absent. Elytra oval; with 9 well-marked striae, interstriae slightly raised, rugous almost serrate, toothed apicad (posterad) and laterad humeri weak. Hind wing not dissected. Forecoxae narrowly separated, distance less than tarsal width, mid-coxae slightly more separate than forecoxae, hind coxae widely separated, distance twice greatest coxal diameter. Mesanepisternal suture distinct, mesanepisternum broadly deltoid, widest anterad, mesepimeral suture distinct, mesepimeron small, deltoid, approximately a quarter the size of mesanepisternum. Metasternum three times wider than long, femoral impression absent; sclerolepidia present; metanepisternum narrow, elongate, almost four times longer than wide; metanepisternal suture becoming obscure posterad; venter sparsely and shallowly punctate, apically. Legs: moderately-sized, femora unarmed; tibiae apically expanded, with strong, curved uncus on outer, anterior (dorsal) margin, foretibia bearing a row of stramineous setae, uncus of mid- and hind tibiae shorter and more blunt, hind tibiae fossorial; tarsi with 4 subequal tarsomeres, linear, fourth tarsomere absent, fifth tarsomere apically acute with 2 distal setae (homology assessment based on the reduction of the fourth tarsomere in most Curculionoidea , however there are Curculionoidea that have five visible tarsomeres, a secondary elongation of 4th tarsomere, as in Dryophthorus Schönherr and Stenommatus Wollaston); tarsal claws obsolete, hind tarsi in lateral view with setose, elongate, sclerotized tarsal extensions (Fig. 1B ). Abdomen: ventrites 1 and 2 without visible suture, apparently fused, ventrites 3-5 as long as 1 and 2 combined. Single specimen not dissected.

Etymology.

The species is named in honor of the late Rémy Lemagnen, who was devoted to the study of weevils on the island of Reunion. The specific epithet also suggests the Latin word for oar (remus) given the weevil’s sand burrowing and ‘rowing’ habit.

Biology.

Halorhynchus geniculatus was reported from saltbush ( Atriplex sp.) from Geraldton, Western Australia ( Lea 1900). Atriplex spp are suffruticose coastal species that have a woody base but apical parts that die off after flowering. Lea (1900) also indicated he found H. caecus on the beach near the roots of spinifex grasses approximately 4 inches below the surface. Atriplex perrieri Leandri is the only species of the genus known to occur on Madagascar, on the coastal areas of the southern part of the country ( Sukhorukov 2013). Given several assumptions, Halorhynchus remii may be found to be associated with Atriplex perrieri or other coastal adapted plant species.

Figures

Figure 1. A-D Halorhynchus remii, new species, holotype A dorsal view B lateral view C anterior view D detail of antenna, lateral view E-H Halorhynchus caecus, NHMUK 014016642, type E dorsal view F lateral view G labels H detail of antenna, lateral view.

Figure 2. A-D Leipommata calcarata, NHMUK 014016712, lectotype A dorsal view B lateral view C labels D detail of antenna, lateral view E-H Onycholips bifurcata, NHMUK 014016644, syntype E dorsal view F lateral view G labels H detail of antenna, lateral view.

Figure 3. A Halorhynchus remii, holotype, ventral view B Distribution of Halorhynchus species: circle: Halorhynchus remii; triangle: Halorhynchus caecus and H. geniculatus C distribution of Dryotribus mimeticus and ocean currents; red lines depict warm surface currents, blue are deeper, cold currents (sources Intergovernental Panel on Climate Change via Smithsonian magazine; rendition by Taina Litwak, USDA ARS SEL).