Twenty-eight new species of Trigonopterus Fauvel (Coleoptera, Curculionidae) from Central Sulawesi

Abstract Here we present 28 new species of Trigonopterus from Central Sulawesi, mostly from Mt Dako and Mt Pompangeo: Trigonopterusacutussp. nov., T.ancorasp. nov., T.arcanussp. nov., T.coronasp. nov., T.dakoensissp. nov., T.daunsp. nov., T.ewoksp. nov., T.gundalasp. nov., T.hopplasp. nov., T.kakimerahsp. nov., T.katopasensissp. nov., T.matakensissp. nov., T.moduaisp. nov., T.monssp. nov., T.paramoduaisp. nov.T.pomberimbensissp. nov., T.pompangeensissp. nov., T.puspoisp. nov., T.rosichonisp. nov., T.rubidussp. nov., T.sarinoisp. nov., T.sutrisnoisp. nov., T.tanahsp. nov., T.tejokusumoisp. nov., T.toboliensissp. nov., T.tolitoliensissp. nov., T.tounaensissp. nov., T.unyilsp. nov. This fills important areas of distribution and brings the number of Trigonopterus species recorded from Sulawesi to 132.


Introduction
Trigonopterus is a hyperdiverse genus of flightless hidden-snout weevils (Cryptorhynchinae) ranging over the Indo-Australian-Melanesian archipelago. It originated in Northern Australia and rapidly diversified in New Guinea (Toussaint et al. 2017) before colonizing Sulawesi and dispersing further west to Sundaland Letsch et al. 2020). Thus, Sulawesi acted as a hub for the dispersal to Borneo, Java and the Lesser Sunda Islands. Currently, there are 451 described species (Riedel et al. 2013b(Riedel et al. , 2014Riedel and Tänzler 2016;Narakusumo et al. 2019;Riedel and Narakusumo 2019), but discovery of new species is still far from approaching saturation, especially if new localities are being sampled. In the following, we report on 28 new species from Central Sulawesi Province, mostly based on two field trips to Mt Dako and Mt Pompangeo, plus four species from Mt Torompupu, Mt Katopasa, and Palu from the collection of "Museum Zoologicum Bogoriense". Mt Dako with a maximum elevation of 2304 m was sampled between 700 and 2200 m. Mt Pompangeo with a maximum elevation of 2590 m was sampled between 1800 and 2000 m. The total of Trigonopterus species in Sulawesi and the adjacent islands was recently brought from a single one to 104 species , and with the present paper to 132 species. We refrain from providing a key based on morphological characters for the same reasons as outlined previously (Riedel and Narakusumo 2019: p. 96). Until the number of described species approaches saturation, a traditional key would be incomplete and potentially highly misleading. Old museum specimens can be hard to identify based on cox1 sequences using a PCR / Sanger sequencing workflow, but in many cases, fragments of degraded DNA will be sufficient to allow sequencing by NGS technologies (Staats et al. 2013). Thus, even dry specimens older than 100 years can be safely identified if deemed necessary.
Sulawesi is geologically complex (Hall 2009;Stelbrink et al. 2012) and its biogeography is currently the subject of a detailed study by us utilizing, among other taxa, the genus Trigonopterus. The purpose of this paper is to provide names to these species, especially as some of them had been part of an earlier study on mitogenomes . While many additional new Trigonopterus species can be expected from Sulawesi, the species described herein fill an important gap in the distributional record (Fig. 29). Central Sulawesi is where the formerly separate geological terranes fused together (Hall 2009;Nugraha and Hall 2018), and its fauna may be one of the richest areas on this island.

Materials and methods
This study is based on 866 specimens from Central Sulawesi Province. Holotypes were selected from 197 specimens for which the cox1 gene had been sequenced. DNA was extracted nondestructively as described by Riedel et al. (2010). Genitalia of most specimens did not require extra maceration. They could be directly stained with an 0.01% alcoholic Chlorazol Black solution and stored in glycerol in microvials attached to the pin of the specimens. Genitalia of specimens with tissue not sufficiently digested after DNA extraction were macerated in a 10% KOH solution and rinsed in 5% 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 the dry collection. Long series of the sibling species T. matakensis sp. nov. and T. pompangeensis sp. nov. could not be assigned based on external characters and had to remain unidentified. Type depositories are cited using the following codens:
The methods applied for DNA sequencing and sequence analysis are the same as described by Riedel et al. (2010) and Tänzler et al. (2012), except for samples MZB0217-MZB0240 being sequenced only in reverse direction using the primer HCO. 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 it appears appropriate. In groups comprising hundreds of species enumerating the absence of rare character states leads to inflated descriptions that distract the reader from the important information, i.e., the diagnostic characters present in a given species.
The closest relatives of Central Sulawesi species were identified by creating an alignment of 773 cox1 sequences representing ca. 185 species and generating a maximum likelihood reconstruction using the program IQTREE (Nguyen et al. 2015). The uncorrected p-distance was calculated using dist.dna function with parameter model="raw" and pairwise.deletion="TRUE", in ape 5.0 package (Paradis and Schliep 2019) run on R 3.6.3 (R Core Team 2020). Morphological terminology follows Beutel and Leschen (2005) and Leschen et al. (2009), i.e., the terms "mesoventrite" / "metaventrite" are used instead of "mesosternite" / "metasternite" 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. Specimens were examined with a Leica MZ16 dissecting microscope and a fluorescent 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. 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 DFC495 camera with L.A.S. 4.8.0 software adapted to a Z6 APO (all from Leica Microsystems, Heerbrugg, Switzerland). Photographic illustrations of genitalia were made using a DFC450 camera with L.A.S. 4.8.0 software adapted to an Axio Imager M2 microscope (Carl Zeiss Microscopy), with 5×, respectively 10× A-Plan lenses; resulting image stacks were compiled using the Helicon Focus 6.7.1 Pro software (Helicon Soft Ltd). For photography genitalia were temporarily embedded in glycerol gelatin as described by Riedel (2005), with their longitudinal axis somewhat lifted caudally, to adequately illustrate structures of the curved down apex. All photographs were enhanced using the programs Adobe Photoshop CS2 and CS6. However, care was taken not to obscure or alter any features of the specimens illustrated. Sequence data were submitted to GenBank of NCBI (National Center for Biotechnology Information) and the accession numbers are provided under each species, e.g., as "(GenBank OK481808)".
Notes. Trigonopterus acutus sp. nov. was coded as "Trigonopterus sp. 1207". This species belongs to the T. tatorensis-group. It is closely related to T. daun sp. nov., from which it can be distinguished by the pointed apex of the penis.
Etymology. This epithet is the Latin noun ancora (anchor) in apposition and refers to the sclerite in the male transfer apparatus.
Notes. Trigonopterus ancora sp. nov. was coded as "Trigonopterus sp. 1114" (Narakusumo et al. 2020). The species belongs to the T. satyrus-group and is closely related to T. rosichoni sp. nov. from which it differs by the shape of the transfer apparatus and 9.4-9.6% p-distance of its cox1 sequence.
Notes. Trigonopterus corona sp. nov. was coded as "Trigonopterus sp. 1235". This species belongs to the T. fulvicornis-group and is related to T. seticnemis Riedel, from which it can be easily distinguished by the ferruginous elytra.
Notes. Trigonopterus daun sp. nov. was coded as "Trigonopterus sp. 1116" (Narakusumo et al. 2020). This species belongs to the T. tatorensis-group. It is closely related to T. acutus sp. nov., from which it can be distinguished by the erect metatibial setae, and the truncated apex of the penis. The cox1 p-distance is 10.0-10.5%.
Notes. Trigonopterus ewok sp. nov. was coded as "Trigonopterus sp. 1188" (Narakusumo et al. 2020). This species belongs to the T. impressicollis-group. It is closely related to T. impressicollis Riedel, which differs by the absence of longitudinal impressions on the pronotum, shorter setae on the apex of penis and 17.5-17.7% cox1 p-distance.
Notes. Trigonopterus hoppla sp. nov. was coded as "Trigonopterus sp. 1232". This species belongs to the T. tatorensis-group. It is closely related to T. daun sp. nov., from which it can be distinguished by the pointed apex of the penis and a cox1 p-distance of 7.8%. The marked difference in sculpture between holotype and the single paratype is remarkable, and would usually indicate a separate species. However, genital morphology and cox1 sequence of both specimens are almost identical, so either the coarse sculpture of the holotype, or the smooth sculpture of the paratype may be an aberration. Additional specimens are needed to clarify this matter.
Notes. Trigonopterus kakimerah sp. nov. was coded as "Trigonopterus sp. 1202". This species may belong to the T. fulvicornis-group. The cox1 p-distance to other known species is above 14%.
Notes. Trigonopterus moduai, sp. nov. was coded as "Trigonopterus sp. 1201" and belongs to the T. arachnobas-group. It is very close to T. paramoduai sp. nov. (3.20-4.11% cox1 p-distance) but can be distinguished by the darker elytral color, a slightly shorter rostrum, and the much longer flagellum of the male genital.

Notes.
Trigonopterus paramoduai sp. nov. was coded as "Trigonopterus sp. 1233" and belongs to the T. arachnobas-group. It is very close to T. moduai sp. nov. (3.20-4.11% cox1 p-distance) from which it can be distinguished by the ferruginous elytral color, a slightly longer rostrum, and the shorter flagellum of the male genital.

Biology. On foliage in montane forest.
Etymology. This epithet is a Latinized adjective based on Mt Pompangeo. Notes. Trigonopterus pompangeensis sp. nov. was coded as "Trigonopterus sp. 1198". This species belongs to the T. ovalipunctatus-group. It is closely related to T. ovalipunctatus Riedel, but differs by a more densely punctate pronotum, the apically extended and converging penis, and 7.2-9.7% cox1 p-distance.
Etymology. This species is named in honor of Saleh Poespo, grandfather of the first author, and for his pioneering animal husbandry science in Indonesia. An invariable genitive.
Notes. Trigonopterus puspoi sp. nov. was coded as "Trigonopterus sp. 1113" ) and belongs to the T. palopensis-group. It is closely related to T. tolitoliensis sp. nov., from which it differs by its simple penis surface, the pubescence of the metatibia, and a 16.4-18.1% p-distance of its cox1 sequence.
Notes. Trigonopterus rosichoni sp. nov. was coded as "Trigonopterus sp. 1193". It belongs to the T. satyrus-group and is closely related to T. ancora sp. nov. from which it differs by the shape of the transfer apparatus and 9.4-9.6% p-distance of its cox1 sequence.
Etymology. This epithet is the Latin adjective rubidus, -a, -um (reddish) referring to the elytral color.
Notes. Trigonopterus rubidus sp. nov. was coded as "Trigonopterus sp. 1199". This species belongs to the T. tatorensis-group. It is closely related to T. tatorensis Riedel, from which it differs by denser pronotal punctures, its reddish elytral color and 9.5-9.9% cox1 p-distance.
Notes. Trigonopterus sarinoi sp. nov. was coded as "Trigonopterus sp. 1208". This species belongs to the T. lampros-group. It is closely related to T. yoda Riedel, which differs by its black-bronze elytral color and a 19.3% cox1 p-distance.
Etymology. This epithet is named in honor of Hari Sutrisno, curator of moths and researcher at MZB. An invariable genitive.
Notes. Trigonopterus sutrisnoi sp. nov. was coded as "Trigonopterus sp. 1206". This species belongs to the T. toraja-group. It is related to T. toboliensis sp. nov., which differs by its lateral extensions of the penis and a cox1 p-distance of 15.3-15.5%.
Etymology. This epithet is the Indonesian word for "soil" and a noun in apposition. It refers to the species´ lifestyle on the ground among leaf litter.
Notes. Trigonopterus tanah sp. nov. was coded as "Trigonopterus sp. 1234". It is closely related to T. darwini Riedel, from which it can be distinguished by its coarser sculpture, and the subparallel body of the penis. The cox1 p-distance of both species is 10.8%.
Etymology. This species is named in honor of Slamet Tedjokoesoemo, pioneer of veterinary science in Indonesia and grandfather of the first author. An invariable genitive.
Notes. Trigonopterus tejokusumoi sp. nov. was coded as "Trigonopterus sp. 1200". This species belongs to the T. barbipes-group. It is most closely related to T. barbipes Riedel, but differs by smaller and more irregular elytral punctures, a peculiar obtuse apex of the penis and a 16% cox1 p-distance.

Trigonopterus unyil sp. nov.
http://zoobank.org/74F11B0E-6885-4F20-8886-7484D5C6EF03 Diagnostic description. Holotype. Male (Fig. 28a). Length 1.52 mm. Color largely ferruginous; thorax, sides of elytra and patch at the middle of intervals 2-3 black. Body subovate; in dorsal aspect and in profile with moderate constriction between pronotum and elytron. Rostrum dorsally with dense coarse punctures, areolatereticulate; with sparse suberect setae; epistome, subglabrous, apically with sparse setae, posteriorly with transverse angulate ridge forming median denticle. Pronotum subapically with weak constriction; disk coarsely punctate, reticulate; each puncture bearing a suberect, clavate, apicad directed, yellowish scale; medially with subglabrous costa, subapically shortened. Elytra with striae marked by rows of suberect subclavate scales; intervals costate, glabrous; basal margin bordered by simple ridge. Femora dentate; anterior surface dull, rugose, but without distinct punctures; with sparse suberect scales. Metafemur dorsally rounded; subapically with stridulatory patch. Abdominal ventrites 1-2 flat, dull, with coarse punctures, with sparse suberect scales; ventrite 5 flat, microreticulate, dull. Penis (Fig. 28b) with sides of body subparallel, towards apex rounded, medially pointed, with sparse setae; tensively between 1970 m and 2000 m. Patches of rainforest remaining in the steeper areas are still at risk being affected by regular forest fires. Both Mt Dako and Mt Pompangeo harbour endemic Trigonopterus species, and presumably additional ones could be discovered if longer field trips are conducted in the remaining forest patches. These forest patches among the Sulawesi rainforest still hold the largely unknown diversity of Trigonopterus and other arthropod species. They should be of greater concern to conservation despite or rather because of their fragmentation.