Exophthalmida elytrodon Yunakov, Bollino, Pancini and Anderson, 2024

Yunakov, Nikolai, Bollino, Maurizio, Pancini, Lorenzo & Anderson, Robert, 2024, Discovery of Elytrurini in Wallacea with a description of Exophthalmida elytrodon sp. nov. from Morotai Island (Coleoptera: Curculionidae: Entiminae), Zootaxa 5537 (2), pp. 270-280 : 272-278

Exophthalmida elytrodon Yunakov, Bollino, Pancini and Anderson sp. nov.

( Fig. 1 )

http://zoobank.org/ urn:lsid:zoobank.org:act:607A555E-0BA9-4E59-A356-0B200A02B4E7

Material examined

Holotype ♀ ( CMNC): INDONESIA: North Maluku / Morotai Island, Daeo village / XI.2018; Alim Yasin . Paratypes: 10 ♂, 10 ♀, same data as holotype ( CMNC, FCSA, NHMUK, USNM) ; 13♂ 7♀ ( NYC): Indonesia — North Maluku / 7 km North Daeo Majiko Village / ( South Morotai—Morotai I.) XII.2019 —m 350-400 / L.A. Yasin —coll. Bollino (one completely dissected female is stored in a plastic tube with alcohol; wing and mouthparts are mounted on microscope slides) ; 6♂, 6♀ ( MBLI): Indonesia — North Maluku / 7 km North Daeo Majiko Village / ( South Morotai—Morotai I.) X.2019 —m 350-400 / L.A. Yasin —coll. Bollino ; 25♂ 7♀ ( MBLI): Indonesia — North Maluku / 7 km North Daeo Majiko Village / ( South Morotai—Morotai I.) XII.2019 —m 350-400 / L.A. Yasin —coll. Bollino. 1♂ 1♀ ( MSNG): INDONESIA: North Maluku, South Morotai Island / Daeo village / XII.2020 — L.A. Yasin . 1♂ ( NHMUK): INDONESIA: North Maluku, South Morotai Island / Daeo village / XII.2020 — L.A. Yasin . 1♂ ( LPPC) INDONESIA: North Maluku, South Morotai Island / Daeo village / XII.2020 — L.A. Yasin .

Diagnosis

This is the largest (BL: 19.07–23.27 mm) species of Exophthalmida , and the only species having long preapical spines on the elytral declivity in females. Remarkably, similar spines are characteristic of other entimines of the Australasian region, i.e. Elytrurus Boisduval, 1835 ( Kuschel 2008) and particularly Ottistira Pascoe, 1872 ( Riedel & O’Brien 1995).

Exophthalmida elytrodon sp. nov. differs from the other known species in fore tarsus with tarsomere 2 strongly transverse (L/W: 0.52–0.68 vs 0.66–0.83 in E. planirostris ; 0.75–0.83 in E. glauca ); mesanepisternum with broad triangular callosity along mesoventrite; occipital suture linear, without transversal callosity. From Exophthalmida coerulescens Günther, 1938 and Exophthalmida glauca Faust, 1892 it differs by females having basal part of elytral interstriae 3, 5, 7 convex and interstria 9 tuberculate. It resembles E. coerulescens (BL: 13–14mm) in general shape and in the tessellate pattern on the elytra but differs by the flattened pronotal tubercles (raised E. coerulescens ); elytra with straight basilateral margins, and punctures on striae mainly united by a thin sulcus; and protibiae only apically curved (in E. coerulescens thinner and more widely curved). It is also similar to E. glauca (BL: 10-13 mm) in the straight basal margin of the elytra directed slightly obliquely towards the scutellum and the humeral calli, but differs from it in having a tessellated pattern on more elongate elytra (EL/EW: 1.59–1.80 vs 1.47 in E. glauca ); rostrum with thin median carina (in E. glauca with three carinae); granules on elytral interstriae poorly visible due to dense scales (in E. glauca granules clearly visible and scales sparse); subgenal suture distinct, covered but not concealed by scales. Preostial portion of median lobe longer, endophallus longer, apical ostial valve and lateral valves significantly shorter, median lobe longer and evenly dorso-ventrally arcuate ( Fig 4A, B, E ). From Exophthalmida planirostris Heller, 1910 (BL: 14–16 mm) it differs in the elytra broadly acuminate; basal margin straight (in E. planirostris narrowly acuminate, and female with basal margin strongly bisinuate), interstriae with one or two rows of minute granules (coarser and irregular in E. planirostris ); rostrum moderately elongate (RL/ RW: 1.06–1.20 vs. 1.35–1.50 in E. planirostris ), epifrons with thin, flat glabrous carina from the median fovea to frons (in E. planirostris abbreviate, faint, does not reach the frons). From E. laticollis Heller, 1915 (BL: 9.5 mm) the new species differs in having the pronotum with a distinct median longitudinal impression (absent in E. laticollis ); epifrons with thin, flat glabrous carina from the median fovea to frons, scape strongly compressed (rostrum tricarinate, and scape slightly compressed in E. laticollis ); scutellum subrounded (distinctly transverse as in E. laticollis ); interstria 9 with strongly developed tubercles (reduced in E. laticollis ).

Description

Measurements (based on 24 specimens): BL mf: 19.07–23.27 (20.61) mm; BW mf: 7.76–10.02 (8.72) mm; BH mf: 6.10–7.61 (6.87) mm; RL/RW mf: 1.06–1.20 (1.13); VW/ELD mf: 0.51–0.72 (0.63); VW/EfrW mf: 0.40– 0.60 (0.47); RBL: 0.92–1.80 (1.14) mm; PL/PW mf: 0.73–0.89 (0.82); EL/BH mf: 1.94–2.35 (2.15); EL/EW mf: 1.59–1.80 (1.69); EL/PL mf: 3.16–3.98 (3.62); BL/EL mf: 1.36–1.44 (1.40); Wftm1/Wftm2 mf: 0.89–0.97 (0.92); Wftm3/Wftm2 mf: 1.37–1.52 (1.41); Lftm5/Lftm3 mf: 1.20–1.54 (1.38); Whtm1/Whtm2 mf: 0.81-0.98 (0.92); Whtm3/Whtm2 mf: 1.38–1.54 (1.44); Lhtm5/Lhtm3 mf: 1.40–1.59 (1.48); IPW/CCW mf: 1.11–1.35 (1.23); AL/ AW mf: 1.04–1.11 (1.09).

Vestiture and Coloration: Integument dark-brown to black. Body, head and legs with vestiture composed of dense, ovate and lanceolate, pale yellowish and brown scales with slight metallic reflection. Scales form a more or less regular tessellated pattern; in females with large transverse pale spot posterior of the middle. Lateral and ventral sides mainly composed of pale yellowish scales, concentrated on metasternum and lateral side of ventrites. Pronotum covered with dense scales that conceal spaces between tubercles, scales concentrated posterolaterally. Mesanepisternum covered with scales, bears large triangular callosity along mesoventrite. Metasternum in males bears long, dense yellowish setae, abdominal sternites 3-7 also with long but less dense pale setae.

Head: Head capsule slightly broadly constricted posteriorly of eyes. Vertex narrow [VW/ELD mf: 0.51–0.72 (0.63)], flat, with a distinct elongate median fovea. Gena shorter than or subequal to vertical diameter of eye. Rostrum moderately elongate [RL/RW mf: 1.06–1.20 (1.13)], widened apically; epistome glabrous; frons with scattered scales laterally delimited from epistome by a row of setae; epifrons with thin, flat glabrous carina from the median fovea to frons. Antennal scrobe terminates shortly anteriorly of eye. Occipital suture (ocs) linear, without transversal callosity. Subgenal suture (sgs) distinct, covered but not concealed by scales. Eyes large, sub-rounded, slightly transversely oval. ( Fig. 2A–C ).

Mouthparts: Mandible moderately protruding from buccal cavity; lateral surface bears 5–7 long setae; scar large, round. Maxilla ( Fig. 3A ) with 9 even long straight lacinial teeth, stipes 1.3x longer than wide, stipes-palpiger joint movable; palpiger bears ~20 setae. Pm1-2 as long as wide, Pm3 1.5x longer than wide with convex sensillar field; ga-se long and dense. Prementim ( Fig. 3B ) trapezoidal without setae. Labial palpomere 1 enlarged, palpomere 2 abbreviated. Ligula small, not extending beyond anterior margin of prementum.

Antennae: Scape straight, strongly compressed (excluding the apex) [maximal width to minimal width ratio: 2.4], which almost reach the apical margin of the pronotum ( Fig. 2D ). Funicle: funicular segment 2 strongly elongate, remaining segments moniliform: L/W fam1 = 1.57–2.55 (2.01), L/W fam2 = 2.09–2.68 (2.35), L/W fam3 = 0.96– 1.49 (1.20), L/W fam4 = 1.03–1.55 (1.26), L/W fam5 = 0.82–1.45 (1.10), L/W fam6 = 0.94–1.26 (1.13), L/W fam7 = 0.94–1.38 (1.17). Club fusiform [CL/CW = 2.77–3.54 (3.23)], with well-defined antennomeres. ( Fig. 2E )

Thorax: Pronotum: Slightly transverse [PL/PW mf: 0.73–0.89 (0.82)], with rounded sides, wider in the middle, with very flattened and scattered shiny tubercles, very approximate and fused along the weak, but distinct median longitudinal impression. Metasternum depressed in the middle, with a fairly large fovea before the posterior margin. Scutellum parallel-sided, with rounded posterior margin, 1.5x longer than wide. Elytra: [EL/EW mf: 1.59–1.80 (1.69)], elongate, with humeral calli, parallel-sided in proximal 2/3, broadly acuminate, in female with spiniform process in preapical part interstria 1; basal margin straight, slightly oblique towards scutellum and humeral calli. Ten striae visible, stria 10 reaches metacoxae, thin, with small circular punctures, mainly united by a thin sulcus. Elytral interstriae wide, with one or two irregular rows of minute, weakly convex shiny granules; in males regularly evenly weakly convex; in female basal part of elytral interstriae 3, 5, 7 distinctly convex, interstria 9 with strongly developed tubercles. Metendosternite: Stalk long, narrow; anterior tendons somewhat convergent medially. ( Fig. 3C ). Metathoracic wings: ( Fig. 3D ) Fully developed, elongate, 1.8x longer than elytra; 3x longer than wide; crossvein between radial system and medial recurrent broad (rm), heavily sclerotized; branch 2 of Cu (Cu2) separated into two fragments; medial stripe (mst) complete, connected to medial sclerotisation (msc); median branch 1 (M1) distinct.

Femora: Edentate, strongly clavate. Tibiae linear with small mucro; protibiae apically curved; metatibiae with a long apical fringe, and corbel closed, lenticular, glabrous, delimited along its inner margin by a fringe of setae, and along outer margin by a row of enlarged tibial surface setae. Tibiae: Bear scattered long pale setae, longer on the inner margin of the protibiae. Metatibial corbel developed, bare. Mucro covered by dense grooming brush. Setal comb of protibia of 16–18 short brown setae not extending beyond lateral margin of tibiae. Tarsi: Large ( Fig. 2F ), tarsomere 1 triangular (L/W ftm1: 0.96–1.16); 2 strongly transverse (L/W ftm2: 0.52–0.62); 3 broad, deeply bilobate (L/W ftm3: 0.65–0.69); 5 sublinear, slightly wider in the middle (L/W ftm5: 3.58–4.18). Claws free.

Abdomen: Intercoxal process somewhat wider than coxal cavity [IPW/CCW mf: 1.11–1.35 (1.23)]. Ventrites finely punctate, slightly elongate [AL/AW mf: 1.04–1.11 (1.09)]; anal ventrite in female subacute, in males obtuse coarsely punctate. ( Fig. 2G, H )

Male genitalia: Median lobe ( Fig. 4A ) elongate (L/W=6.11), apically subacute; apodemes 0.36x as long as median lobe. Endophallus in rest folded inside median lobe; endophallic sclerite spiniform, with developed flagellar sheath; apical ostial valve oblong; lateral ostial valves small, ovate (visible in base of everted endophallus). Everted endophallus ( Fig. 4B ): Bean-shaped, with a developed ventrobasal bump, followed by a short tubuliform portion that ends with a ventral bump smaller than the basal one; subglobose ventroapical bump, from which the heavily sclerotized ejaculatory duct emerges, transformed into the flagellar sheath of endophallic sclerite (es-fs); apical ostial valve (aov) with a small, sharp-tipped protuberance located about halfway along its length. Sternite 9 well sclerotized, composed of lanceolate hemisternites. ( Fig. 4D ).

Female genitalia: Ovipositor heavily sclerotized, lanceolate; baculum well developed from basal margin of coxite to basal margin of valvifer; styli elongate. Sternite 8: lamina sagittate, biapical, densely setose apically; apodeme 2.5x as long as lamina, basal part of apodeme forked, caput of apodeme not defined. Spermatheca Jtype; nodulus swollen, elongate, enlarged compared to cornu, with basal appendix (no-a); ramus reduced; collum pedunculate. Spermathecal duct short. Bursa copulatrix reduced. ( Fig. 4C ).

Distribution and biogeography

North Maluku: Morotai Island. The genus Exophthalmida is one of a growing number of curculionid genera that transverse Lydekker’s Line and now has a species occurring in Wallacea. ( Fig. 5A ). The discovery of Exophthalmida elytrodon sp. nov. on Morotai Island challenges previous biogeographic assumptions about the distribution of Elytrurini , which were thought to be confined to regions eastward of New Guinea. Further exploration of other islands in Wallacea may yield more exciting discoveries.

Figures

FIGURE 1. Exophthalmida elytrodon sp.n., morphology. A. Dorsal and B. Lateral habitus of female, holotype; C. Dorsal, and D. Lateral habitus of male, paratype.

FIGURE 2. Exophthalmida elytrodon sp.n., morphology. A. Head dorsal, B. Lateral, C. Ventral view. D. Antennal scape, E. Funicle, F. Fore tarsus of male, G. Female ventrites, H. Male ventrites. Abbreviations: see Material and Methods.

FIGURE 3. Exophthalmida elytrodon sp.n., morphology. A. Maxilla, B. Prementum, C. Metendosternite, D. Metathoracic wing. Abbreviations: see Material and Methods.

FIGURE 4. Exophthalmida elytrodon sp.n., morphology. A. Aedeagus dorsal and lateral view. B. Female genitalia lateral and ventral view. C. Male sternites 8 and 9. D. Everted endophallus. E. Everted endophallus of Exophthalmida glauca Faust, 1892. Abbreviations: see Material and Methods.

FIGURE 5. Distribution maps. A. Exophthalmida species. B. Elytrurini.