Revision of the Australian species of the weevil genus Trigonopterus Fauvel

Abstract The Australian species of the genus Trigonopterus Fauvel are revised. Eight previously recognized species are redescribed and 24 additional new species are described: Trigonopterus allaetus Riedel, sp. n., Trigonopterus athertonensis Riedel, sp. n., Trigonopterus australinasutus Riedel, sp. n., Trigonopterus australis Riedel, sp. n., Trigonopterus bisignatus Riedel, sp. n., Trigonopterus bisinuatus Riedel, sp. n., Trigonopterus boolbunensis Riedel, sp. n., Trigonopterus cooktownensis Riedel, sp. n., Trigonopterus daintreensis Riedel, sp. n., Trigonopterus deplanatus Riedel, sp. n., Trigonopterus finniganensis Riedel, sp. n., Trigonopterus fraterculus Riedel, sp. n., Trigonopterus garradungensis Riedel, sp. n., Trigonopterus hasenpuschi Riedel, sp. n., Trigonopterus hartleyensis Riedel, sp. n., Trigonopterus kurandensis Riedel, sp. n., Trigonopterus lewisensis Riedel, sp. n., Trigonopterus montanus Riedel, sp. n., Trigonopterus monteithi Riedel, sp. n., Trigonopterus mossmanensis Riedel, sp. n., Trigonopterus oberprieleri Riedel, sp. n., Trigonopterus robertsi Riedel, sp. n., Trigonopterus terraereginae Riedel, sp. n., Trigonopterus yorkensis Riedel, sp. n.. All new species are authored by the taxonomist-in-charge, Alexander Riedel. Lectotypes are designated for the following names: Idotasia aequalis Pascoe, Idotasia albidosparsa Lea, Idotasia evanida Pascoe, Idotasia laeta Lea, Idotasia rostralis Lea, Idotasia sculptirostris Lea, Idotasia squamosa Lea. A new combination of the name Idotasia striatipennis Lea is proposed: Trigonopterus striatipennis (Lea), comb. n.. A key to the species is provided. Australian Trigonopterus occur in coastal Queensland, narrowly crossing into New South Wales. The southern parts of the range are inhabited by species found on foliage. A rich fauna of 19 edaphic species inhabiting the leaf litter of tropical forests is reported for the first time from the Australian Wet Tropics.


Introduction
Trigonopterus Fauvel is a genus of wingless weevils of the subfamily Cryptorhynchinae (Alonso-Zarazaga and Lyal 1999) and highly species-rich in the tropical forests of southeast Asia and Melanesia (Tänzler et al. 2012). New Guinea appears to be the center of its diversity, with more than 300 species recorded (Riedel 2010, Tänzler et al. 2012. Trigonopterus is currently the subject of studies on its ecology , Tänzler et al. 2012, biogeography , Tänzler et al. 2016) and functional morphology (van de Kamp et al. 2011, van de Kamp et al. 2014, van de Kamp et al. 2015. The need for a stable taxonomy with valid names became urgent, and a fast-lane approach of taxonomy (Riedel et al. 2013a) was established to describe 200 new species from Indonesia and Papua New Guinea (Riedel et al. 2013b. The number of Australian Trigonopterus species is relatively small. Nevertheless, from a biogeographical perspective this continental and presumably old fauna is of great interest. Eight species have been described from Queensland to date (Pullen et al. 2014). A study of museum collections and a limited amount of field work resulted in the discovery of a modest number of additional, undescribed species. Many of them were first collected by Geoff Monteith (QMBA), who also discovered an edaphic group of species by sifting leaf litter. All the previously known Australian species had been collected from vegetation.
Despite these advances there are problems remaining. Some Australian Trigonopterus are difficult to characterize using morphological characters alone: species of the T. politus-group (e.g., comprising the Australian T. aequalis Pascoe, T. evanidus Pascoe and T. albidosparsus (Lea)) and of the T. squamosus-group offer only few morphological characters, whereas molecular data indicate highly divergent lineages. Therefore we have to leave many museum specimens unidentified. Still, we believe that it is timely to present a first summary now, with the aims of 1) redescribing the known species based on their type material and 2) providing names for those new species that can be safely recognized based on morphological characters alone. Hopefully this study will instigate the additional field work needed to arrive at a more comprehensive understanding of the Australian Trigonopterus fauna.

Materials and methods
This study is based on 673 specimens, including 11 type specimens of old collections. Some of the material was collected specifically for this project from vegetation with the help of a beating sheet, or by sifting the litter of primary forests and subsequent extraction of specimens from it using Winkler eclectors (Besuchet et al. 1987). DNA sequences were obtained for 86 of the freshly collected specimens. Holotypes of new species were selected from these sequence vouchers whenever possible. DNA was extracted nondestructively as described by Riedel et al. (2010). Type and other old specimens from collections were treated in the same way, which has also proved to be the most conservative method for the extraction of genitalia and at the same time allows saving the presumably more or less degraded DNA. Unfortunately all our trials of PCR using this old collection material failed, but it may be feasible in future with improved sequencing methods. The genitalia of most specimens did not require maceration after DNA extraction and could be directly stained in an alcoholic solution of chlorazol black and stored in glycerol in microvials attached to the pin of the specimens. Genitalia of specimens whose abdominal muscle tissue was not sufficiently digested after DNA extraction were macerated in a 10% KOH solution and rinsed in 3% acetic acid before staining. Illustrations of habitus and genitalia were prepared from holotypes. Finally, type series were supplemented with specimens stored in ethanol and older material from museum collections. Type depositories are cited using the following codens:

ANIC
Australian National Insect Collection, Canberra, Australia BMNH The Natural History Museum, London, UK QMBA Queensland Museum, Brisbane, Australia SAMA South Australian Museum, Adelaide, Australia SMNK Staatliches Museum für Naturkunde, Karlsruhe, Germany The methods applied for DNA sequencing and sequence analysis are described by Riedel et al. (2010) and Tänzler et al. (2012). Morphological descriptions are limited to major diagnostic characters, as outlined by Riedel et al. (2013a, b). Negative character states (i. e. the absence of a character) are only mentioned explicitly where this appears appropriate. For example, some species of the T. politus-group have a weakly carinate dorsal margin of the eyes. In these cases the character is described, but for the majority of species, in which the eyes are dorsally simple and evenly rounded with the forehead, this condition is not mentioned. Common practice would require stating explicitly "eyes dorsally simple, rounded with forehead". Although formally accurate, in groups comprising hundreds of species this leads to inflated descriptions that distract the reader from the important information by enumerating the absence of rare character states.
Morphological terminology follows Beutel and Leschen (2005) and Leschen et al. (2009), i.e. the terms "mesoventrite" / "metaventrite" are used instead of "mesosternum" / "metasternum", and "mesanepisternum" / "metanepisternum" instead of "mesepisternum" / "metepisternum"; "penis" is used instead of "aedeagus" as the tegmen is usually without useful characters in Trigonopterus and therefore omitted from species descriptions. Descriptions were prepared using a Leica MZ16 dissecting microscope and a fluorescent-light desk lamp for illumination. Measurements were taken with the help of an ocular grid. The length of the body was measured in dorsal aspect from the elytral apex to the front of the pronotum. The width of the elytra was measured between the humeri at their greatest extent and across both elytra. Legs were described in an idealized laterally extended position; there is a dorsal / ventral and an anterior / posterior surface. Habitus illustrations were compiled using a DFC450 camera with L.A.S. 4.6.0 software adapted to a Z6 APO (all from Leica Microsystems, Heerbrugg, Switzerland). Photographic illustrations of genitalia were made using a JVC KY70 camera (JVC Professional Products) adapted to an Axio Imager M2 microscope (Carl Zeiss Microscopy), with 5× or 10× A-Plan lenses; the resulting image stacks were combined using the Helicon Focus 6.2.2 software (Helicon Soft Ltd). For photography the genitalia were temporarily embedded in glycerol gelatin, as described by Riedel (2005), with their longitudinal axis somewhat lifted anteriorly to adequately illustrate structures of the down-curved apex. All photographs were enhanced using Adobe Photoshop CS2 and CS6, but care was taken not to obscure or alter any features of the specimens illustrated.
Sequence data were submitted to the European Molecular Biology Laboratory (EMBL), and the accession numbers are provided under each species e.g. as "(EMBL # LN888232)". Data on genetic material contained in this paper is published for noncommercial use only. Utilization for purposes other than non-commercial scientific research may infringe the conditions under which the genetic resources were originally accessed, and should not be undertaken without contacting the corresponding author of the paper and/or seeking permission from the original provider of the genetic material.
Material examined. Type specimens. Male, lectotype by present designation ( Distribution. New South Wales: Tamworth. Notes. Pascoe (1872) did not designate a holotype nor specify the number of specimens examined but gave two localities, "Cape York" and "Rockhampton". Only the syntype from the first locality could be located in the BMNH. Presumably the missing syntype from Rockhampton represents a different species. A lectotype is designated here to achieve stability of nomenclature.
The question mark behind the name of the type locality ("Cape York ?") suggests that there was doubt about its validity already in Pascoe's times. This is supported by the fact that we could only examine one additional specimen, identified by Lea, from the village of Warrah, south of Tamworth in New South Wales. Additional field work should verify the occurrence of the species in this area.
Etymology. This epithet is a combination of the Latin prefix ad-(next to; near) and the specific epithet of T. laetus (Lea), a closely related species.
Etymology. This epithet is a combination of the Latin adjective australis (southern) and the specific epithet of T. nasutus (Pascoe), also an adjective.
Notes. This species is closely related to T. nasutus (Pascoe) and T. gibbirostris (Faust) from New Guinea. From the former it can be distinguished by a longer and spiniform transfer apparatus, from the latter by its medially pointed apex of the penis.
Biology. Sifted from leaf litter in primary forest; occasionally found in pitfall traps. Etymology. This epithet is a combination of the Latin prefix bi-(two) and the participle sinuatus (curved) and refers to the outline of the elytral base.
Distribution. Queensland: Mt. Boolbun. Biology. Sifted from leaf litter in primary forest. Etymology. This epithet is an adjective and refers to the name of the type locality, Mt. Boolbun.
12. Trigonopterus deplanatus Riedel, sp. n. http://zoobank.org/A0B05E4E-B897-4A78-941D-E0B9F4B48EB3 Diagnostic description. Holotype (Fig. 12a). Length 2.98 mm. Color black; antenna and legs ferruginous. Body with marked constriction between pronotum and elytron; in profile convex. Rostrum in basal half with median costa and pair of submedian costae, intervening furrows with rows of mesad directed setae; in apical third scabrous; epistome posteriorly with transverse ridge; base dorsally weakly protruding, weakly projecting from profile. Forehead coarsely punctate. Pronotum subquadrate, sides weakly converging, apex subtruncate; disk punctate-reticulate; interspaces between punctures narrow,   Fig. 13e). Length 3.19 mm. Color black. Body subovate, almost without constriction between pronotum and elytron; in profile evenly convex. Rostrum with median costa and pair of submedian ridges; intervening furrows with rows of white scales; apical 1/3 rugose-punctate. Eyes with dorsal margin bordered by furrow. Forehead sparsely punctate. Pronotum with disk densely punctate with small punctures; interspaces not microreticulate; sides foveate; base medially weakly extended towards elytral suture. Elytra subglabrous, striae marked by very shallow lines; along base and humeri with row of large punctures; apex with dense rows of small shallow punctures. Legs. Femora microreticulate, punctate. Metafemur dorsally with elongate patch of dense white scales; posterior surface with ventral edge rimmed by costa and row of scales, with longitudinal furrow containing row of scales parallel to indistinct dorsoposterior edge. Mesotibia apically with uncus and larger premucro fused in basal half, diverging in apical half. Metatibia apically with uncus and small angular premucro. Abdominal ventrite 2 swollen, with posterior edge projecting, medially forming common cavity with ventrite 1; ventrite 5 concave, dull, microreticulate, punctate. Penis (Fig. 13f) with sides of body subparallel; apex with median triangular extension somewhat confluent with outline of apex; transfer apparatus short, dentiform, bordered by S-shaped sclerites; ductus ejaculatorius without bulbus. Female lectotype (Fig. 13a-d). As male except: length 2.56 mm. Rostrum punctate-rugose, with weak  Notes. The lectotype here designated has a circular label reading "Holotype" fixed to its pin by staff of the BMNH, but Pascoe (1872) did not designate a holotype in the original description nor specify the number of specimens examined. As other syntypes may exist, we here designate the one in the BMNH as the lectotype to ensure stability of nomenclature in case additional syntypes are discovered that belong to different species.

Etymology. This species is named in honor of Jack Hasenpusch (Garradunga), who preserves the habitat of this and other Trigonopterus species on his insect farm.
Notes. Trigonopterus hasenpuschi Riedel, sp. n. was coded as "Trigonopterus sp. 554".
Biology. Beaten from foliage in rainforest. Notes. Lea (1913) did not designate a holotype in the original description nor specify the number of specimens examined. The original description is based on more than one specimen. One pair with the male marked "TY" and one syntype from Sue Island could be examined, but other specimens may exist. The male is here designated as lectotype.
Etymology. This epithet is based on the adjective montanus (belonging to a mountain) and refers to the isolated occurrence of the species on the summit of Mt. Bellenden Ker.
Biology. Sifted from leaf litter in primary forest.
Etymology. This species is named in honor of Geoff Monteith (Brisbane), who collected the majority of the new Australian Trigonopterus species for the first time and whose help was essential for the success of this study.
Diagnostic description. Lectotype (Fig. 29a). Length 2.10 mm. Color ferruginous; integument partly covered with brown or white scales, partly abraded. Body subrhomboid, with weak constriction between pronotum and elytron; in profile evenly convex. Rostrum with median ridge and pair of less distinct submedian ridges; covered with white scales. Eyes large, in subdorsal position. Forehead punctate, covered with brown scales. Pronotum coarsely punctate, covered with scales inserting at punctures, interspaces polished; disk clothed with brown scales, laterally and subapically with white scales. Elytra with striae deeply incised, narrow; intervals flat, each with two rows of scales largely covering surface, sutural interval with only one row; abraded scales leaving small punctures at point of insertion; subbasally and subapically clothed with white scales, remainder with brown scales and sparse white scales. Legs. Fore-and hind leg broken off and glued separately to card; largely covered with white scales except subglabrous posterior face of mesoand metafemur. Profemur with anteroventral ridge basally abruptly ending forming blunt angle; with subovate, slightly concave subbasal callus. Tibial apex with uncus and minute premucro. Abdominal ventrite 1-2 laterally swollen, medially concave. Penis (Fig. 29b) Fig. 29e), ARC4036 (PCR failed). Female, paralectotype (SAMA), ARC4035 (PCR failed), same data as lectotype. Other specimens (QMBA, SMNK): Queensland: 7 exx, Fraser Isl., Lake Allom, S25°11', E153°13', ANZES Exped., XI-1992. Distribution. Queensland: Caloundra, Fraser Isl.. Biology. Beaten from foliage of undergrowth in relatively dry forest. Notes. Lea (1928) did not designate a holotype in the original description nor specify the exact number of specimens examined. One pair with the female marked "TY" could be examined but other specimens may exist. The male syntype is here designated lectotype. The diagnosis of this species is difficult, and E. C. Zimmerman (unpublished note in QMBS) and Pullen et al. (2014) considered its name to be synonymous with that of T. striatipennis (Lea). However, specimens collected at one locality of North Stradbroke Island fall into two highly divergent clusters based on CO1 sequences. These sequence clusters are correlated with relatively subtle differences in the male genitalia. One is identical to the species described from North Stradbroke Island by Lea (1928), i.e. T. striatipennis; the other is close to T. squamosus. There remains some uncertainty whether all populations of this complex belong to the same two sibling species or if additional cryptic species exist. Sequence data from specimens of additional localities need to be analyzed for a final clarification. The specimen illustrated by Zimmerman (1992, p. 377, plate 492) shows a specimen of T. striatipennis Lea.

Trigonopterus striatipennis (Lea), comb. n.
Idotasia striatipennis Lea, 1928: 155. Diagnostic description. Holotype (Fig. 30a). Length 2.43 mm. Color ferruginous; integument partly covered with brown or white scales, largely abraded. Body subovate; with weak constriction between pronotum and elytron; in profile evenly convex. Rostrum in apical half with submedian rows of punctures, sparsely covered with white scales. Eyes large, in subdorsal position. Forehead punctate, covered with brown scales. Pronotum coarsely punctate, covered with scales inserting at punctures, interspaces polished; disk clothed with brown scales, laterally and subapically with white scales. Elytra with striae deeply incised, narrow; intervals flat, each with two rows of scales largely covering surface, sutural interval with only one row; abraded scales leaving small punctures at point of insertion; subbasally and subapically clothed with white scales, remainder with brown scales and sparse white scales. Legs. Left foreleg broken off and missing; largely covered with white scales except subglabrous posterior face of meso-and metafemur and where abraded. Profemur with anteroventral ridge basally abruptly ending forming blunt angle; with subovate, slightly concave subbasal callus. Tibial apex with uncus, without premucro. Abdominal ventrites 1-2 medially flat. Terminalia (Fig. 30b). Male (ARC3663, Fig. 30e). Male rostrum with median ridge and pair of submedian ridges; covered with white scales. Abdominal ventrites 1-2 laterally swollen, medially concave. Penis (Fig. 30f)  Notes. Lea (1928) stated in his description that the "type" was a "unique" specimen, and it therefore has to be regarded as the holotype. Regarding the distinction of this species from T. squamosus (Lea), see the remarks above. Diagnostic description. Holotype (Fig. 31a). Length 2.50 mm. Color black; antenna and legs ferruginous. Body subovate, in dorsal aspect with marked constriction between pronotum and elytron; in profile convex. Rostrum with median ridge and pair of submedian ridges; intervening furrows with rows of coarse punctures each containing one mesad directed scale; epistome posteriorly with curved ridge. Forehead coarsely punctate-rugose. Pronotum with sides subparallel, anteriorly abruptly rounded to distinct subapical constriction; irregularly foveate-reticulate; each fovea containing one inconspicuous seta. Elytra with striae deeply incised, with coarse punctures; intervals costatecarinate; subglabrous, sparsely punctate, with sparse scales; base bisinuate. Legs. Femora densely punctate. Profemur with subbasal callus anteriorly projecting. Tibiae subbasally with acute tooth; metatibia with suprauncal tooth. Abdominal ventrite 1 concave; abdominal ventrite 2 posteriorly transversely costate. Penis (Fig. 31b) with sides of body subparallel, apex subangulate, medially rounded; orifice with pair of curved sclerites; transfer apparatus short, dentiform; ductus ejaculatorius subapically with weak bulbus. Diagnostic description. Holotype (Fig. 32a). Length 1.84 mm. Color black, antenna and tarsi ferruginous. Body subrhomboid, without constriction between pronotum and elytron; in profile evenly convex. Rostrum punctate-rugose, with sparse white scales, median ridge indistinct. Eyes large, in subdorsal position. Forehead punctate, with scattered brown scales. Pronotum coarsely punctate, interspaces between punctures polished; with sparse narrow brown scales inserting in punctures. Elytra subglabrous; striae marked by indistinct rows of minute punctures each containing minute narrow brown scale; at apical margin with few white almond-shaped scales. Legs. Femora dorsally clothed with white scales; anteroventral furrow with sparse row of white scales. Profemur with anteroventral ridge basally abruptly ending forming blunt angle; with somewhat indistinct subbasal callus. Tibial apex with uncus, without premucro. Abdominal ventrites 1-2 laterally swollen, medially concave; ventrite 5 coarsely punctate, at middle concave. Penis (Fig. 32b) with sides of body subparallel to subangulate apex; transfer apparatus simple, elongate, with pair of small basal sclerites; ductus ejaculatorius without bulbus. Intraspecific variation.  Distribution. Queensland: Mt. Misery, Massey Range. Biology. Beaten from foliage in relatively dry forest. Etymology. This epithet is an adjective based on the Cape York Peninsula, where the type locality is located.

Discussion
The most recent description of an Australian Trigonopterus species prior to this study was by Lea in 1928, reflecting a general taxonomic neglect of Australian Cryptorhynchinae, and in particular of the small sized Trigonopterus. The hitherto described species are found on foliage, whereas all the edaphic species dwelling in the leaf-litter are undescribed -a result agreeing with observations on other groups of tropical insects (Stork et al. 2008). Many of the new edaphic species are endemic to small areas of tropical forest on mountains of the Cape York Peninsula. Most likely, wingless weevils are sensitive to environmental changes, e.g. a warming climate (Staunton et al. 2014), and, considering their high level of endemism, they should be of concern to conservation. The Australian Trigonopterus fauna is divided into a few species-groups, each restricted to geographical areas and specific life-styles: the edaphic fauna inhabiting leaf litter is shared among the T. australis and T. bisinuatus-groups. The former ranges with three species from Cooktown to the Iron Range, whereas the 16 species of the latter occur between Mission Beach and the Mt. Finnigan area. A few less diverse speciesgroups found on foliage are restricted to the northern Cape York, i.e. the T. nasutusgroup (a single species from the Iron Range) and the T. illitus-group (three species in the area north of Cooktown). The T. politus and the T. squamosus-groups are relatively widespread and can be found on foliage in coastal areas ranging from northern New South Wales to the Cape York Peninsula. The taxonomy of these two species groups is problematic and could not be dealt with adequately herein, because male genital as well as external characters are relatively uniform among different species. This situation is unfortunate as the T. politus-group comprises the greatest ecological band width of the Australian Trigonopterus -its numerous species occur in wet rainforests as well as savannah habitats. Furthermore, the T. politus-group represents the largest portion of Australian Trigonopterus specimens stored in collections; in many cases these are incorrectly identified, if identified at all. Therefore, identification records of T. aequalis Pascoe, T. albidosparsus Lea and T. evanidus Pascoe should be treated with caution. Presumably a dense sampling of specimens with molecular data covering the east coast of Queensland and northern New South Wales would be the most efficient way to delineate species boundaries reliably. Thus, a solution of these taxonomic problems mainly depends on freshly collected material suitable for DNA sequencing. The geographical ranges and ecologies of these "difficult species" will become sufficiently clear with such a study, hopefully allowing the safe identification of all the unnamed specimens stored in museum collections.  (6) Pronotum dorsally with coarse punctures (Fig. 19a)