Monograph |
Corresponding author: Alexander Riedel ( riedel@smnk.de ) Academic editor: Miguel Alonso-Zarazaga
© 2019 Raden Pramesa Narakusumo, Michael Balke, Alexander Riedel.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Narakusumo RP, Balke M, Riedel A (2019) Seven new species of Trigonopterus Fauvel (Coleoptera, Curculionidae) from the Tanimbar Archipelago. ZooKeys 888: 75-93. https://doi.org/10.3897/zookeys.888.38642
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Based on recent fieldwork, the hyperdiverse weevil genus Trigonopterus Fauvel is recorded for the first time from the Indonesian Tanimbar Archipelago, halfway between Australia and Western New Guinea. All seven species discovered on Tanimbar are new to science, and described here: Trigonopterus atuf sp. nov., T. kumbang sp. nov., T. laratensis sp. nov., T. porg sp. nov., T. selaruensis sp. nov., T. tanimbarensis sp. nov., and T. triradiatus sp. nov. The new species are authored by the taxonomists-in-charge, Raden Pramesa Narakusumo and Alexander Riedel. This fauna appears discordant and established by relatively recent dispersal from New Guinea and other Moluccan islands.
Coleoptera, conservation, cox1, Cryptorhynchinae, DNA barcoding, endemism, hyperdiverse, integrative taxonomy, Moluccas, morphology, Southeast Asia, Tanimbar, turbo-taxonomy, Wallacea, weevils.
Trigonopterus Fauvel is a genus of hidden snout weevils (Cryptorhynchinae) (
The relatively rich Trigonopterus faunas of Sulawesi and Sundaland originated by dispersal from New Guinea and subsequent diversification (
Here, we present the results of a recent survey of the Tanimbar Archipelago, or simply Tanimbar. Tanimbar is a cluster of islands located approximately halfway between Australia in the south (Darwin area, ca. 320 km distant) and Western New Guinea in the north (ca. 340 km). The island of Timor is ca. 380 km to the west, and the Kai and Aru Islands lie ca. 150 km and 240 km, respectively, to the northeast. The Tanimbar Islands are all low, i.e., below an elevation of 300 meters. The climate is relatively seasonal, and forest cover comprises of seasonal evergreen forest, dry deciduous forest and moist deciduous forest (
Here we describe seven new species of Trigonopterus from Yamdena, Larat, and Selaru islands, the three biggest islands of the Tanimbar Archipelago. We follow the “fast-track” taxonomy approach that combines molecular and morphological systematics (
This study is based on 222 specimens of Trigonopterus collected on two field trips to the Tanimbar Islands by the first author. Specimens were collected by beating foliage in primary forest. Holotypes were selected from 44 DNA sequenced specimens. DNA was extracted nondestructively as described by
The methods applied for DNA sequencing and sequence analysis are described by
The closest relatives of Tanimbar species were identified by creating an alignment of 1.154 cox1 sequences representing ca. 1000 species and generating a maximum likelihood reconstruction using the program IQTREE (
Trigonopterus insignis Fauvel, 1862.
Fully apterous genus of Cryptorhynchinae s. s. Length 1.5–6.0 mm. Rostrum in repose not reaching middle of mesocoxa. Scutellar shield completely absent externally. Mesothoracic receptacle deep, posteriorly closed. Metanepisternum completely absent externally. Elytra with nine striae (sometimes superficially effaced). Tarsal claws minute. Usually body largely unclothed, without dense vestiture. For additional information, see http://species-id.net/wiki/Trigonopterus.
Holotype. Male (Fig.
Holotype (MZB): MZB0014 (GenBank # MN322570), Indonesia, Maluku, Tanimbar, Yamdena Is, Lorulun, 07°48.788'S, 131°22.443'E to 07°48.137'S, 131°21.873'E, 140 m, beaten, 2-V-2017. Paratypes (MZB, SMNK): Indonesia, Maluku, Tanimbar: 13 exx, MZB0012 (EMBL # MN322578) MZB0013 (GenBank # MN322580) MZB0015 (GenBank # MN322569) same data as holotype; 3 exx, MZB0017 (GenBank # MN322568), MZB0018 (GenBank # MN322567), MZB0024 (GenBank # MN322579), Selaru Is, Bangruti, 08°07.253'S, 131°02.947'E, 35 m, beaten, 22-IV-2018; 5 exx, MZB0031 (GenBank # MN322577), MZB0032 (GenBank # MN322576), MZB0040 (GenBank # MN322571), Yamdena Is, Lorulun, Jungle Camp, 07°46.46'S, 131°20.482'E, 110 m, beaten, 19-IV-2018; 1 ex, MZB0034 (GenBank # MN322574), Yamdena Is, Lorulun, Jungle track, 07°47.396'S, 131°20.849'E, 120 m, beaten, 19–20-IV-2018; 47 exx MZB0038 (GenBank # MN322573), MZB0039 (GenBank # MN322572), Yamdena Is, Lorulun, Jungle camp, 07°46.46'S, 131°20.482'E, 110 m, beaten, 24-IV-2018; 2 exx, MZB0033 (GenBank # MN322575), Yamdena Is, Lorulun, Jungle camp, 07°46.46'S, 131°20.482'E, 110 m, beaten, 27-IV-2018.
Maluku Prov., Tanimbar (Yamdena Is, Selaru Is). Elevation: 35–120 m.
On foliage in lowland forest.
The epithet is a noun in apposition. Atuf is a mythical warrior from the folklore of the Tanimbar people who defeated the sun.
This species is closely related to Trigonopterus species 773 from New Guinea, which differs by having a more distinct punctation and 15.1% p-distance of its cox1 sequence.
Holotype. Male (Fig.
Holotype (MZB): MZB0002 (GenBank # MN322581), Indonesia, Maluku, Tanimbar, Yamdena Is, Lorulun, 07°48.788'S, 131°22.443'E to 07°48.82'S, 131°21.524'E, 140 m, beaten, 29-IV-2017. Paratypes (MZB, SMNK): Indonesia, Maluku, Tanimbar: 7 exx, MZB0001 (GenBank # MN322586), MZB0003 (GenBank # MN322585) same data as holotype; 1 ex, MZB0026 (GenBank # MN322582), Yamdena Is, Lorulun, Jungle Camp, 07°46.46'S, 131°20.482'E, 112m, beaten, 24-IV-2018; 3 exx, MZB0042 (GenBank # MN322584), Larat Is, Nature Reserve, 07°08.747'S, 131°49.092'E, 90 m, beaten, 25–26-IV-2018; 1 ex, MZB0019 (GenBank # MN322583), Larat Is, Nature reserve, 07°08.747'S, 131°49.092'E, 90 m, beaten, 26-IV-2018; 5 exx, Yamdena Is, Lorulun, 07°48.473'S, 131°22.266'E to 07°48.137'S, 131°21.873'E, 140 m, beaten, 02-V-2017.
Maluku Prov., Tanimbar (Yamdena Is, Larat Is). Elevation 90–140 m.
On foliage in lowland forest.
This epithet is the Indonesian word for beetle and a noun in apposition.
This species is closely related to the undescribed Trigonopterus species 929 (T. nasutus-group) from the D´Entrecasteaux Islands from which it differs by its smaller body size, a subglabrous side of the pronotum, and a 12.3% p-distance of its cox1 sequence.
Holotype: Male (Fig.
Holotype (MZB): MZB0022 (GenBank # MN322587), Indonesia, Maluku, Tanimbar, Larat Is, Nature reserve, 07°08.747'S, 131°49.092'E, 85 m, beaten, 25–26-IV-2018. Paratype (SMNK): Indonesia, Maluku, Tanimbar: 1 ex, MZB0027 (GenBank # MN322588), Yamdena Is, Lorulun, Jungle Camp, 07°46.46'S, 131°20.482'E, 110 m, beaten, 24-IV-2018.
Maluku Prov., Tanimbar (Yamdena Is, Larat Is). Elevation: 85–110 m.
On foliage in lowland forest.
This epithet is based on the type locality Larat Island.
This species belongs to the T. politus group. It is most closely related to a clade comprising T. allotopus Riedel, T. pseudallotopus Riedel, and some undescribed species from New Guinea, but it has no close relationship to the clade of Australian species.
Holotype. Male (Fig.
Maluku Prov., Tanimbar (Larat Is). Elevation ca. 85 m.
On foliage in lowland forest.
This epithet is a noun in apposition based on the fictional penguin-like character Porg in the Star Wars movies. This species inhabiting a remote island has the same color combination of black, orange and white.
This species is closely related to the undescribed species 437 from Kai Kecil Island from which it differs by the elytral color and a 13.6% p-distance of its cox1 sequence.
Holotype: Female (Fig.
Holotype (MZB): MZB0023 (GenBank # MN322592), Indonesia, Maluku, Tanimbar, Selaru Is, Bangruti, 08°07.253'S, 131°02.947'E, 35 m, beaten, 22-IV-2018.
Maluku Prov., Tanimbar (Selaru Is). Elevation 35 m.
On foliage in lowland forest.
This epithet is an adjective derived from the species´ type locality, Selaru Island.
This species is closely related to the undescribed Trigonopterus species 436 from Kai Kecil Island, from which it differs by a larger body size and a more densely punctate pronotum and an 8.9% p-distance of its cox1 sequence.
Holotype. Male (Fig.
Holotype (MZB): MZB0010 (GenBank # MN322598), Indonesia, Maluku, Tanimbar, Yamdena Is, Lorulun, 07°48.788'S, 131°22.443'E to 07°48.137'S, 131°21.873'E, 140 m, beaten, 02-V-2017. Paratypes (MZB, SMNK): Indonesia, Maluku, Tanimbar: 7 exx, MZB0008 (GenBank # MN322600), MZB0009 (GenBank # MN322599), MZB0011 (GenBank # MN322593), same data as holotype; 4 exx. MZB0035 (GenBank # MN322596), Yamdena Is, Lorulun, Jungle Camp, 07°46.46'S, 131°20.482'E, 110 m, beaten, 19-IV-2018; 53 exx. MZB0028 (GenBank # MN322597) MZB0037 (GenBank # MN322594), Yamdena Is, Lorulun, Jungle Camp, 07°46.46'S, 131°20.482'E, 110 m, beaten, 24-IV-2018; 1 ex., MZB0036 (GenBank # MN322595), Yamdena Is, Lorulun, Jungle Track, 07°47.396'S, 131°20.849'E, 120 m, beaten, 19–20-IV-2018.
Maluku Prov., Tanimbar (Yamdena Is). Elevation 110–140 m.
On foliage in lowland forest.
This epithet is an adjective derived from the Tanimbar Archipelago.
This species appears related to a species from New Guinea (species 959) from which it is differs by 19.9% p-distance of its cox1 sequence and many morphological characters.
Holotype. Male (Fig.
Holotype (MZB): MZB0007 (GenBank # MN322604), Indonesia, Maluku, Tanimbar, Yamdena Is, Lorulun, 07°48.788'S, 131°22.443'E to 07°48.137'S, 131°21.873'E, 140 m, beaten, 2-V-2017. Paratypes (MZB, SMNK): Indonesia, Maluku, Tanimbar: 12 exx, MZB0004 (GenBank # MN322607), MZB0005 (GenBank # MN322606), MZB0006 (GenBank # MN322605) same data as holotype; 3 exx, Yamdena Is, Lorulun, 07°48.788'S, 131°22.443'E to 07°48.137'S, 131°21.873'E, 140 m, beaten, 28–29-V-2017; 7 exx, MZB0029 (GenBank # MN322601) MZB0030 (GenBank # MN322602) Yamdena Is, Lorulun, Jungle Camp, 07°46.46'S, 131°20.482'E, 110 m, beaten, 24-IV-2018; 1 ex, Yamdena Is, Lorulun, Jungle Camp, 07°46.46'S, 131°20.482'E, 110 m, beaten, 19-IV-2018; 1 ex, MZB0021 (GenBank # MN322608) Larat Is, margin of Nature reserve, 07°08.22'S, 131°49.49'E, 40 m, 25-IV-2018; 1 ex, MZB0041 (GenBank # MN322603) Larat Is, Nature reserve, 07°08.747'S, 131°49.092'E, 85 m, beaten, 25–26-IV-2018; 2 exx, MZB0025 (GenBank # MN322609), MZB0112 (GenBank # MN322610), Selaru Is, Bangruti, 08°07.253'S, 131°02.947'E, 40 m, beaten, 22-IV-2018.
Maluku Prov., Tanimbar (Yamdena Is, Larat Is, Selaru Is). Elevation: 40–140 m.
On foliage in lowland forest.
This epithet is an adjective based on triradiate sclerites in the endophallus of the species.
This species is closely related to Trigonopterus species 60 from Papua New Guinea from which it differs by the structure of the penis and a 17.8% p-distance of its cox1 sequence.
1 | Metafemur subapically with stridulatory patch. Pronotum densely punctate | 2 |
– | Metafemur subapically without stridulatory patch. Pronotum subglabrous, sparsely punctate with small or minute punctures | 3 |
2 | Elytra black. Basal half of rostrum and forehead with silvery scales not covering the surface. Side of pronotum anteriorly without scales | T. tanimbarensis sp. nov. |
– | Elytra ferruginous. Basal half of rostrum and forehead almost covered by white scales. Side of pronotum anteriorly with white scales | T. porg sp. nov. |
3 | Femora with simple anteroventral ridge; edentate | 4 |
– | Femora with ventral denticle | 6 |
4 | Eyes medially approximate; base of rostrum much wider than forehead between eyes. Apex of male mesotibia only with uncus | 5 |
– | Base of rostrum subequal to forehead between eyes. Apex of male mesotibia with enlarged premucro | T. laratensis sp. nov. |
5 | Body slender. Pronotum sparsely punctate. Elytral striae marked by rows of minute punctures and fine hairlines | T. atuf sp. nov. |
– | Body wider. Pronotum subglabrous. Elytra subglabrous, without distinct striae | T. triradiatus sp. nov. |
6 | Elytral base bordered by row of deeper punctures. Apex of metatibia with supra-uncal denticle | T. selaruensis sp. nov. |
– | Elytral base without deeper punctures (except row hidden behind humerus). Apex of metatibia dorsally of uncus rounded | T. kumbang sp. nov. |
Trigonopterus had hitherto been recorded from Ceram Island (
All the discovered species of Tanimbar Trigonopterus live on foliage, and no edaphic lineage could be found. This may be due to the relatively dry climatic conditions, which may be putting stress on species that depend on a layer of moist litter. Alternatively, it is possible, that edaphic species are present but have eluded discovery so far; sifting of leaf litter under the right conditions, e.g., after sufficient rainfalls, may bring them to light.
Morphologically the Tanimbar Trigonopterus species are very different from each other, a fact supported by the molecular dataset of their cox1 sequences. Therefore, no closely related species pairs can be recognized, i.e., there is no indication for any autochthonous speciation on the Tanimbar Archipelago. Instead, the Trigonopterus fauna has been formed largely by repeated dispersal from neighboring regions, i.e., from Western New Guinea and the Moluccas. The sister species of T. porg sp. nov. (13.6% p-distance of cox1) and T. selaruensis sp. nov. (8.9% p-distance of cox1) were both found on Kai Kecil Island 190 km to the Northeast. Trigonopterus triradiatus sp. nov. is related to Trigonopterus species 60 from Papua New Guinea (17.8% p-distance of cox1). Trigonopterus laratensis sp. nov. belongs to a clade comprising T. allotopus Riedel, T. pseudallotopus Riedel, and some undescribed species from New Guinea (15.6% p-distance of cox1), but has no close relationship to the clade of Australian species of the T. politus-group. Trigonopterus kumbang sp. nov. belongs to the T. nasutus-group and appears most closely allied to Trigonopterus species 929 (12.3% p-distance of cox1) from the D’Entrecasteaux Islands. Trigonopterus atuf sp. nov. is closely related to Trigonopterus species 773 (15.1% p-distance of cox1) from Papua New Guinea. Trigonopterus tanimbarensis sp. nov. appears related to a species from New Guinea (Trigonopterus species 959; 19.9% p-distance of cox1).
With its close proximity to Australia, stronger ties to the Australian fauna could be expected, but apparently this is not the case. An explanation could be that the Australian species are largely restricted to the Cape York Peninsula and the east coast of Queensland, which is quite distant from the Tanimbar Islands, and that the absence of Trigonopterus from the Northern Territory in Australia could be a real gap in the distribution of the genus and not just a sampling artifact, caused by environmental extremes.
All in all, the observed composition of the Trigonopterus fauna of the Tanimbar Archipelago is exactly what can be expected from the geological setting and what has been observed in other taxa (
The rapid and ongoing anthropogenic activities in Tanimbar, i.e., agriculture and forestry, put pressure on the natural forests of the islands, which are the exclusive habitats of Trigonopterus species. The first author found the southern part of Yamdena Island to be extensively logged, and most areas of the eastern coast have been converted to agriculture and settlements. The forests of Larat Island are also severely affected by agriculture, with coconut plantations prevalent inside the wildlife conservation area. Finally, Selaru Island without any protected areas, has suffered worst from logging; its interior has already been turned into grassland and the remaining forests areas are fragmented on the sparse rocky soil that is almost useless for gardening. Such destructions of natural forest areas in Tanimbar threaten not only the endemic Trigonopterus species but also the remaining biodiversity of this fascinating archipelago.
We would like to thank the Indonesian Ministry of Environment and Forestry and Center for natural resources conservation (BKSDA) of Maluku for the permits to enter conservation areas and to collect wildlife. Specimens were exported as a loan from MZB. Thanks to Anang Setiawan Achmadi (MZB) and Ibnu Maryanto (MZB) for making it possible that RPN could join their expedition to the Tanimbar Archipelago. Special thanks to Wilhelmus Samangun (Tanimbar), Vera (Tanimbar), Mark O’Hara (Vienna), Berenica Mioduszewska (Vienna), and Tri Haryoko (MZB) in allowing RPN to use their wonderful field station, Suprayitno (Denpasar) for the companionship during the first trip, and I Nyoman Sumerta (InaCC), Ruby Setiawan (InaCC), and the people of Lorulun, Adaut, and Keliobar for helping RPN during the fieldwork. Sequencing runs were done by A. Brachmann and G. Brinkmann of the LMU sequencing unit (Munich). This work was funded by the German Academic Exchange Service DAAD (91654661 to R.P.N.), pilot project funding from the laboratory of Michael Balke, DIPA KSK Pengembangan Database KEHATI PDII 2018 and the German Research Foundation DFG (RI 1817/3-4 to A.R.).