Research Article |
Corresponding author: Alexander Riedel ( riedel@smnk.de ) Academic editor: Miguel Alonso-Zarazaga
© 2022 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:
Riedel A (2022) Nine new species of Trigonopterus Fauvel (Coleoptera, Curculionidae) from Sundaland. ZooKeys 1124: 109-130. https://doi.org/10.3897/zookeys.1124.89318
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The DNA of Trigonopterus specimens from the Sundaland region stored between ten and 32 years in museums could be used for next-generation sequencing. The availability of their cox1 sequence allowed the description of the following nine new species: Trigonopterus grimmi sp. nov., T. johorensis sp. nov., T. lambirensis sp. nov., T. linauensis sp. nov., T. microreticulatus Riedel, Trnka & Wahab sp. nov., T. mulensis sp. nov., T. sarawakensis sp. nov., T. siamensis sp. nov., and T. singaporensis sp. nov. The alternative original spelling of the name T. tounensis Narakusumo & Riedel is chosen to prevail over T. tounaensis Narakusumo & Riedel. The new species represent the first country records of Trigonopterus for Brunei, Singapore, and Thailand. Thus, the genus´ known area of distribution in the Sundaland region is significantly extended. A key and a catalogue are provided to the Trigonopterus species from Borneo, W-Malaysia, Singapore, and Thailand.
Ancient DNA, Cryptorhynchinae, DNA barcoding, endemism, hyperdiverse, integrative taxonomy, morphology, turbo-taxonomy
Trigonopterus is a hyperdiverse genus of flightless weevils (Curculionidae, Cryptorhynchinae) ranging over the Indo-Australian-Melanesian archipelago. It originated in northern Australia and rapidly diversified in New Guinea (
This study is based on 46 museum specimens from the Sundaland region. Holotypes were selected from ten specimens for which the cox1 gene had been sequenced. DNA was extracted nondestructively as described by
SMNK Staatliches Museum für Naturkunde, Karlsruhe, Germany;
UBDC Universiti Brunei Darussalam, Brunei;
UPOL Palacky University, Olomouc, Czech Republic.
The methods applied for DNA sequencing differ from our earlier publications as the fragmented DNA of collection vouchers was not suitable for amplifying longer fragments by PCR. Instead, sequencing libraries were prepared with the NEBnext ultra II kit (New England Biolabs, Ipswich, Massachusetts, USA) and tagged with universal dual indexes. Procedures were followed the manufacturer´s protocol except that only half of the recommended volumes were used, i.e., starting with 25 µl of genomic DNA template containing 1.73–18.33 ng DNA. Resulting libraries were quantified using a Qubit 3.0 Fluorometer with the dsDNA HS assay kit (Thermo Fisher Scientific, Waltham, MA, USA). Fragment distribution of libraries was examined using a Fragment Analyzer dsDNA 910 kit (Agilent Technologies, Santa Clara, CA, USA) for a range of 35 to 1,500 bp. Based on the concentration and the average size distribution, the molar concentration was calculated for each sample. The ten samples of this project were pooled in equimolar amounts together with other samples and submitted to Novogene Inc. (Cambridge, U.K.) for sequencing. Libraries of samples ARC1453 (T. linauensis sp. nov.), ARC5226 (T. johorensis sp. nov.), ARC5227 (T. singaporensis sp. nov.) were sequenced using an Illumina Hiseq X 10, while samples ARC7266 (T. siamensis sp. nov.), ARC7267 (T. sarawakensis sp. nov.), ARC7268 (T. microreticulatus Riedel, Trnka & Wahab sp. nov.), ARC7269 (T. lambirensis sp. nov.), ARC7270 (T. grimmi sp. nov.), ARC7272 (T. mulensis sp. nov.) were sequenced on an Illumina Novaseq, in each case for 2 × 150 bp. Reads were processed, assembled and annotated as described earlier (
Morphological descriptions are limited to major diagnostic characters as outlined by
Morphological terminology follows
Trigonopterus insignis Fauvel, 1862, by monotypy.
Fully apterous genus of Cryptorhynchinae. Length 1.5–6.0 mm. Rostrum in repose not reaching center 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
(
Holotype, male (Fig.
Sarawak (Gn. Gading NP). Elevation: ca. 50–300 m.
The species is named for the late darkling beetle expert Roland Grimm, who collected the type series of this species. The epithet is a noun in the genitive case.
Trigonopterus grimmi sp. nov. is coded as “Trigonopterus sp. 1247”. This species belongs to the T. trigonopterus group. It is closely related to T. trigonopterus Riedel, 2014, from which it can be distinguished by its flat elytral intervals and 17.3% p-distance of its cox1 sequence.
Holotype
(
Holotype, male (Fig.
Malaysia (Johor). Elevation: 100 m.
This epithet is a Latinized adjective based on the name of the Malaysian state Johor.
Trigonopterus johorensis sp. nov. is coded as “Trigonopterus sp. 1112”. This species belongs to the T. attenboroughi group. It is closely related to T. attenboroughi Riedel, 2014, T. mulensis sp. nov., and T. sarawakensis sp. nov., from which it can be distinguished by the subtruncate elytral apex and 13.7–15.3% p-distance of its cox1 sequence.
Holotype
(
Holotype, male (Fig.
Sarawak (Lambir-Hills NP). Elevation: 200 m.
This epithet is a Latinized adjective based on Lambir-Hills NP.
Trigonopterus lambirensis sp. nov. is coded as “Trigonopterus sp. 1246”. Morphologically it appears related to T. microreticulatus Riedel, Trnka & Wahab sp. nov., from which it can be distinguished by the rather polished elytral intervals, the morphology of the penis and 20.9% p-distance of its cox1 sequence. A comprehensive molecular analysis will need to determine its phylogenetic position.
Holotype (SMNK): ARC1453 (GenBank # OP078704), E-Malaysia, Sarawak, Belaga, Long Linau, logging camp, ca. 02°45'N, 113°46'E, ca. 400 m, 19-III-1990. Paratypes (ARC in SMNK): 2 exx, same data as holotype.
Holotype, male (Fig.
Sarawak (Belaga). Elevation: ca. 400 m.
This epithet is a Latinized adjective based on the type locality Long Linau.
Trigonopterus linauensis sp. nov. is coded as “Trigonopterus sp. 1123”. This was the first species of Trigonopterus that I personally collected. At the time, I did not fully appreciate the scientific value of the specimens. This species belongs to the T. attenboroughi group. It is closely related to T. sepuluh Riedel, 2014 and T. singkawangensis Riedel, 2014, from which it can be distinguished by the more slender elytral apex, the morphology of the penis and 18.6–19.2% p-distance of its cox1 sequence.
Holotype
(
Holotype, male (Fig.
Sarawak (Mulu NP); Brunei (Ulu Temburong NP). Elevation: 100–200 m.
This epithet is an adjective formed as a compound of the Greek mikros (small) plus the Latin reticulatus (netted) and refers to the elytral microsculpture.
Trigonopterus microreticulatus Riedel, Trnka & Wahab sp. nov. is coded as “Trigonopterus sp. 1245”. Morphologically it appears related to T. lambirensis sp. nov., from which it can be distinguished by the microreticulate elytra, the morphology of the penis and 20.9% p-distance of its cox1 sequence. A comprehensive molecular analysis will need to determine its phylogenetic position. It is described under joint authorship with Rodzay Abdul Wahab (Universiti Brunei Darussalam, Tungku, Brunei) and Filip Trnka (Palacky University, Olomouc, Czech Republic).
Holotype
(
Holotype, male (Fig.
Sarawak (Mulu NP). Elevation: 200 m.
This epithet is a Latinized adjective based on Mulu NP.
Trigonopterus mulensis sp. nov. is coded as “Trigonopterus sp. 1248”. This species belongs to the T. attenboroughi group. It is closely related to T. attenboroughi Riedel, 2014 and T. sarawakensis sp. nov., from which it can be distinguished by its dense white scales of the metatibia and 9.2–10.3% p-distance of its cox1 sequence.
Holotype
(
Holotype. Male (Fig.
Sarawak (Mt. Santubong). Elevation: ca. 200–400 m.
This epithet is a Latinized adjective based on Sarawak.
Trigonopterus sarawakensis sp. nov. is coded as “Trigonopterus sp. 1244”. This species belongs to the T. attenboroughi group. It is closely related to T. attenboroughi Riedel, 2014 and T. mulensis sp. nov., from which it can be distinguished by the subangulate apex of the penis and 8.2–9.2% p-distance of its cox1 sequence.
Holotype
(
Holotype, male (Fig.
Thailand (Ko Chang Is.).
This epithet is a Latinized adjective based on Siam, the former name of Thailand.
Trigonopterus siamensis sp. nov. is coded as “Trigonopterus sp. 1243”. This species belongs to the T. trigonopterus group. It is related to T. singaporensis sp. nov., from which it can be distinguished by its elytral intervals 3–5 each with a row of coarse punctures and 18.1% p-distance of its cox1 sequence. It would be important to confirm the locality of this species by additional records.
Holotype
(
Holotype, male (Fig.
Singapore (Bukit Timah). Elevation: 100 m.
This epithet is a Latinized adjective based on the island of Singapore.
Trigonopterus singaporensis sp. nov. is coded as “Trigonopterus sp. 742”. This species belongs to the T. trigonopterus group. It is related to T. siamensis sp. nov., from which it can be distinguished by its costate-carinate elytral intervals never having rows of coarse punctures and 18.1% p-distance of its cox1 sequence.
Map of the new Trigonopterus species of the T. trigonopterus group across the Sundaland area. Prepared using GeoMapApp (www.geomapapp.org; ;
Map of other new Trigonopterus species. Prepared using GeoMapApp (www.geomapapp.org;
In the abstract of
1 | Body small, 1.52–1.79 mm. Epistome with dorsoposteriad directed horn and rostrum at middle with dorsal protrusion | T. wallacei Riedel, 2014 |
– | Body larger, 1.95–3.20 mm. Epistome at most with minute denticle; rostrum with longitudinal ridges but without dorsal protrusions | 2 |
2 | Pronotum anteriorly with flanges projecting laterally. Anteroventral ridge of meso- and metafemur denticulate | T. sebelas Riedel, 2014 |
– | Pronotum anteriorly simple. Anteroventral ridge of meso- and metafemur simple or crenate, but not denticulate | 3 |
3 | Elytra with humeri swollen, more or less projecting laterad between mid- and hind leg. Penis with very long apodemes and long flagelliform transfer apparatus | 4 |
– | Elytra with humeri simple, not swollen and projecting between mid- and hind leg. Penis with dentiform transfer apparatus (except T. lambirensis sp. nov.), usually with additional endophallic sclerites | 7 |
4 | Elytral striae marked by lines and rows of small punctures, not deeply impressed; elytral intervals flat | T. grimmi sp. nov. |
– | Elytral striae deeply impressed; intervals costate or weakly carinate | 5 |
5 | Elytra ferruginous, humeri markedly projecting | T. trigonopterus Riedel, 2014 |
– | Elytra black, humeri less projecting | 6 |
6 | Elytral intervals 3–5 costate, each with row of coarse punctures; punctation of humeri coarse, confused | T. siamensis sp. nov. |
– | Elytral intervals costate-carinate, with few small punctures; humeri with regular punctation | T. singaporensis sp. nov. |
7 | Body in dorsal aspect subrotund | 8 |
– | Body in dorsal aspect subovate | 9 |
8 | Elytra dull, microreticulate. Penis with dentiform transfer apparatus | T. microreticulatus Riedel, Trnka & Wahab, sp. nov. |
– | Elytra with interspaces between punctures subglabrous. Penis with flagelliform transfer apparatus | T. lambirensis sp. nov. |
9 | Elytral apex with suture distinctly incised. Abdominal ventrite 2 in profile simple | 10 |
– | Elytral apex with suture simple, not incised. Abdominal ventrite 2 in profile projecting dentiform | 11 |
10 | Penis as in fig. 16b; endophallus containing numerous coarse denticles, apically with pair of relatively small sclerites | T. bornensis Riedel, 2014 |
– | Penis as in fig. 41b; endophallus with complex structures, several sclerites, containing few denticles | T. kalimantanensis Riedel, 2014 |
11 | Penis apically with median incision | 12 |
– | Penis apically truncate or angulate, without median incision | 15 |
12 | Body slender subrhomboid. Penis with shallow median incision, with sparse setae | T. linauensis sp. nov. |
– | Body subovate. Penis apically bisinuate, with deep incision, without setae | 13 |
13 | Elytral apex subtruncate. West Malaysia | T. johorensis sp. nov. |
– | Elytral apex rounded. Borneo | 14 |
14 | Metatibia posteriorly with dense white subclavate scales. Penis with large π-shaped sclerite | T. mulensis sp. nov. |
– | Metatibia posteriorly with sparse yellowish scales. Penis with endophallic sclerite compressed and folded along middle | T. attenboroughi Riedel, 2014 |
15 | Profemur in basal half posteroventrally with slightly bifid tooth. Male metatibia ventrally with dense fringe of long, stiff setae | T. santubongensis Riedel, 2014 |
– | Profemur in basal half posteroventrally without tooth. Male metatibia with sparse rows of setae | 16 |
16 | Base of rostrum in profile simple, evenly confluent with forehead | 17 |
– | Median ridge of rostrum swollen in front of forehead, projecting subangularly from profile | 18 |
17 | Color entirely black. Penis as in |
T. sepuluh Riedel, 2014 |
– | Color of legs and elytra dark ferruginous. Penis (Fig. |
T. sarawakensis sp. nov. |
18 | Penis as in |
T. bawangensis Riedel, 2014 |
– | Penis as in |
T. singkawangensis Riedel, 2014 |
Specimens of Trigonopterus found in two museum collections represented not only new species, but also very notable distribution records. While the hitherto known range of the genus reached its western limit in Lampung province of East Sumatra, the new records from the Malay Peninsula and from a small island off the coast of Thailand extend it considerably to the west and northwest respectively. Since the record from Thailand is represented by a unique specimen and the collector visited Borneo on other trips, there is a small chance of confounded samples. A successful search for additional specimens at the type locality could settle these doubts. However, the biogeographic picture of the T. trigonopterus group is one of numerous, genetically divergent species spread over the area of the Sunda shelf. A clade ranging from Borneo to Singapore and the coast of Thailand is not out of the ordinary. Since most of the species from Java and Sumatra (
T. attenboroughi group: T. attenboroughi Riedel, T. bawangensis Riedel, T. johorensis sp. nov., T. linauensis sp. nov., T. mulensis sp. nov., T. santubongensis Riedel, T. sarawakensis sp. nov., T. sebelas Riedel, T. sepuluh Riedel, T. singkawangensis Riedel.
T. bornensis group: T. bornensis Riedel, T. kalimantanensis Riedel.
T. trigonopterus group: T. grimmi sp. nov., T. trigonopterus Riedel, T. siamensis sp. nov., T. singaporensis sp. nov.
T. wallacei group: T. wallacei Riedel.
Incertae sedis: T. lambirensis sp. nov., T. microreticulatus Riedel, Trnka & Wahab sp. nov.
I thank R Oberprieler (Canberra) and A Faille (Stuttgart) for the loan of specimens. MA Alonso-Zarazaga (Madrid), M Balke (Munich), CHC Lyal (London), and GP Setliff (Kutztown) are thanked for their helpful comments on the manuscript. This work was funded by the German Research Foundation DFG (RI 1817/ 5-1).