Research Article |
Corresponding author: Wen-Bin Yeh ( wbyeh@nchu.edu.tw ) Academic editor: Thorsten Assmann
© 2019 Ming-Hsun Chou, Wen-Bin Yeh.
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:
Chou M-H, Yeh W-B (2019) Delineation of two new, highly similar species of Taiwanese Cylindera tiger beetles (Coleoptera, Carabidae, Cicindelinae) based on morphological and molecular evidence. ZooKeys 875: 31-62. https://doi.org/10.3897/zookeys.875.37856
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Tiger beetles have been recognized primarily based on morphological characters. However, the variations of elytral maculation and coloration sometimes lead to misjudgment in species classification and the overlooking of the existence of cryptic species. Recently, specimens of two endemic species of Taiwanese Cylindera, C. sauteri and C. pseudocylindriformis, exhibit morphologically recognizable forms, indicating that some undescribed species may exist. To clarify their taxonomic status, morphological characteristics including male genitalia were examined and two mitochondrial genes, COI and 16S rDNA, and one nuclear 28S rDNA were analyzed. Molecular phylogenetic inferences indicated that both forms in both species are reciprocally monophyletic. Moreover, molecular dating showed the forms diverged approximately 1.3 million years ago. Two new species, Cylindera ooa sp. nov. and Cylindera autumnalis sp. nov., are thereby described. The main recognizable characteristics separating C. ooa sp. nov. from C. sauteri are the lack of a triangular spot at the middle edge of elytron and the elongated but not rounded subapical spot. For C. autumnalis sp. nov., the apical lunula near the elytral suture is thickened but not linear and slender, and its elytra are more metallic brownish than those of C. pseudocylindriformis. Although their aedeagi characteristics are not distinctive, the body size of the proposed two new species is different. Field observation revealed that niche utilization would be relevant for differentiating these closely related species.
COI, key, new species, taxonomy, 16S rDNA, 28S rDNA
The subfamily Cicindelinae of Carabidae consists of approximately 2,600 species (
Cicindela sauteri and C. cylindriformis were described by
Recently, some specimens examined exhibit morphologically recognizable variations, which represents the possibility of undescribed Cylindera species in Taiwan. Field observation showed that C. pseudocylindriformis, inhabiting the soil slopes with gravels and litters near the forest, has a dark brownish body color and is seldom found on open ground. Several tiger beetles, however, collected from Pintung county, in southern Taiwan, are morphologically similar to C. pseudocylindriformis in elytral maculation pattern but have more obvious spots and lighter metallic coloration and inhabit the open forest trails. For C. sauteri, two forms were discovered in the specimens deposited in Museums für Naturkunde Berlin (
Tiger beetles were determined and described mainly based on morphological characters (
Molecular evidence has been helpful for systematic work in tiger beetles, such as the sequences of cytochrome oxidase I (COI), 16S rDNA, and 28S rDNA (
Cylindera adults were collected by net around Taiwan. For the ‘sauteri’ group, 23 individuals of C. sauteri were sampled, and seven individuals of Kosempo form were collected in Jiaxian (Kosempo), Kaohsiung. As for the ‘pseudocylindriformis’ group, 11 individuals each of C. pseudocylindriformis and the Pintung form were collected. The sampling localities are shown in Fig.
Sampling localities of the ‘sauteri’ and ‘pseudocylindriformis’ groups. Map was modified from the base map in website of Graduate Institute of Applied Geology of National Central University (http://gis.geo.ncu.edu.tw/earth/shade/twshades.htm).
KK Kosempo (Jiaxian), Kaohsiung, Taiwan
KD Daliao, Kaohsiung, Taiwan
MS Sanyi, Miaoli, Taiwan
NH Huisun Forest Area, Nantou, Taiwan
NL Lianhuachi, Nantou, Taiwan
PS Shuangliu Forest Recreation Area, Pintung, Taiwan
YF Fushan, Yilan, Taiwan
Genomic DNA was extracted from the adult’s thoracic or leg muscle. A piece of tissue was ground in 50-μL solution of the QuickExtract DNA extraction kit (Epicentre Biotechnologies, Madison, WI), and then the sample solution was incubated at 65 °C for 10 min, followed by 98 °C for 2 min. After incubation, the sample solution was stored at -20 °C for polymerase chain reaction (PCR).
Primer pairs used to amplify COI, 16S rDNA, and 28S rDNA are listed in Table
Genes | Primers | Sequences (5’–3’) | References |
---|---|---|---|
COI | Col46 (+) | AACCATAAAGATATTGGAAC | Tsai et al. 2014 |
Col731 (-) | CCAAAAAATCAAAATAAATGTTG | Tsai et al. 2014 | |
LCO1490 (+) | GGTCAACAAATCATAAAGATATTGG |
|
|
HCO2198 (-) | TAAACTTCAGGGTGACCAAAAAATCA |
|
|
16S rDNA | 16SR21(+) | GCCTGTTTATCAAAAACAT |
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16S22 (-) | CCGGTCTGAACTCAGATCA |
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|
28S rDNA | 28Se (+) | TCCGTAACTTCGGAACAAGGATT |
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28Sf (-) | TGTACCGCCCCAGTCAAACT |
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DNA sequences were aligned using the ClustalW multiple alignment program and then edited in Bioedit 7.0 (
Cylindera redunculata belonging to the same subgenus Cylindera s. str. was used as the phylogenetic outgroup. Sequences of COI, 16S rDNA, and 28S rDNA were used to perform phylogenetic analyses. The best-fit substitution models applied to different genes were inferred in jModelTest 2.1 (
Divergence time estimation was performed in BEAST 2.5.1 (
Body lengths were measured using Microsight 4.1.2 connected with a Canon EOS 800D camera (Tokyo, Japan); this equipment was also used for imaging aedeagi. Specimens images were taken using a Nikon Coolpix B700 camera (Tokyo, Japan) with a Raynox DCR-250 macrolens (Tokyo, Japan). To avoid influencing the measurement by head pose, lengths of the pronotum and elytron were applied as body length. R 3.4.3 (
Male genitalia of both forms were dissected and dipped in 10% KOH solution at room temperature for 12 h. The treated genitalia were preserved in glycerol for imaging and then described (
‘sauteri’ group. Twenty-five sequences of COI, 16S rDNA, and 28S rDNA with a length of 660 bp, 472–473 bp, and 850 bp, respectively, were obtained and aligned. The combined data indicated that Kosempo form and C. sauteri were reciprocally monophyletic groups with high support values (ML = 0.99, BI = 1 for each of them) (Fig.
‘pseudocylindriformis’ group. There were 17, 19, and 18 sequences of COI, 16S rDNA, and 28S rDNA of lengths 661 bp, 471 bp, and 848 bp, respectively, that were obtained and aligned. The ML tree based on combined data showed the reciprocal monophyly of Pintung form and C. pseudocylindriformis with high support of values (ML = 0.96, BI = 1 for Pintung form; ML = 0.87, BI = 1 for C. pseudocylindriformis) (Fig.
Morphological and genital characteristics described for sauteri and pseudocylindriformis groups were as follows:
‘sauteri’ group. Body lengths (pronotum and elytron) of Kosempo form were 5.91–6.67 mm (mean = 6.44 mm, n = 7) for males and 6.95–7.53 mm (mean = 7.26 mm, n = 8) for females, and the lengths of C. sauteri, including the specimens borrowed from
Elytral maculation of Kosempo form mostly included two spots on each elytron: One spot near elytral suture (Fig.
The elytral maculations (left elytron). 7 Kosempo form lacks any spot on the middle elytral edge and has one spot near suture (a) and one subapical spot (b) 8 Cylindera sauteri has one spot near suture (c), one subapical spot (d), and one triangular spot on the elytral middle edge (e).
Male genitalia were very similar in external shape and inner sac between Kosempo form (n = 3) and C. sauteri (n = 8) but different in size (Figs
‘pseudocylindriformis’ group. Body lengths (pronotum and elytron) of Pintung form were 6.57–7.11 mm (mean = 6.79 mm, n = 7) for males and 7.14–7.72 mm (mean = 7.42 mm, n = 4) for females and of C. pseudocylindriformis, 5.77–6.43 mm (mean = 6.16 mm, n = 6) for males and 6.96–7.59 mm (mean = 7.16 mm, n = 5) for females (Fig.
The pattern of elytral maculation of Pintung form and C. pseudocylindriformis almost identical (details provided below Figs
Male genitalia similar in morphology between C. pseudocylindriformis (n = 5) and Pintung form (n = 4) and even similar to sauteri group. External shape slender, median portion widened, apical portion narrow gradually with a rounded apical top, basal portion slightly shorter in C. pseudocylindriformis and slenderer in Pintung form. Paramere (p) slender, acanthoid. Structures of inner sac almost identical in both forms, base of flagellum (f) convoluted spirally on left view; stiffening rib (sr) near base of flagellum; central plate (cp) irregular; medial tooth (mt) and arciform piece (ap) oblique near subapical apex and overlap partially (Figs
Phylogenetic trees inferred from molecular combined data show that both forms in sauteri and pseudocylindriformis groups are monophyletic reciprocally with high support values (Figs
According to the original description of C. sauteri (
Based on the genetic distinction and stable morphological differences, Kosempo form and Pintung form could be recognized as two undescribed species. In the present study, Kosempo form of the sauteri group is named Cylindera ooa sp. nov., and Pintung form of the pseudocylindriformis group is named Cylindera autumnalis sp. nov. Moreover, C. ooa sp. nov. seems to be confined to the Jiaxian region, but C. sauteri is widely distributed across the Taiwan Island. The type localities of C. sauteri are Kosempo (Jiaxian, Kaohsiung) and Taihorin (Dalin, Chiayi) (
Ecological niche differentiation in sympatric closely related species could be related to morphological divergence such as body size because of different resource utilization (
Moreover, the subgenus Cylindera s. str. of Taiwan possessing a comparatively longitudinally elongated labrum, thoracic proepisternum with hairs (C. sauteri and C. ooa sp. nov.), well developed hind wings for flight, and a more slender body seems morphologically distinct from the other members of the subgenus Cylindera s. str.
Holotype:
male (Fig.
Species | Code | Type of type | Original label | In English |
---|---|---|---|---|
Cylindera ooa | AdeC66-1 | Holotype | Locality: 高雄甲仙六義山 | Locality: Kaohsiung, Jiaxian, Liuyi Mountain |
Date: 2018.V.17 | Date: 2018.V.17 | |||
Collector: 周明勳 | Collector: Ming-Hsun Chou | |||
Code: AdeC66-1 | Code: AdeC66-1 | |||
AdeC66-2 | Paratype | Locality: 高雄甲仙六義山 | Locality: Kaohsiung, Jiaxian, Liuyi Mountain | |
Date: 2018.V.17 | Date: 2018.V.17 | |||
Collector: 周明勳 | Collector: Ming-Hsun Chou | |||
Code: AdeC66-2 | Code: AdeC66-2 | |||
AdeC66-15 | Paratype | Locality: 高雄甲仙六義山 | Locality: Kaohsiung, Jiaxian, Liuyi Mountain | |
Date: 2018.V.18 | Date: 2018.V.18 | |||
Collector: 周明勳 | Collector: Ming-Hsun Chou | |||
Code: AdeC66-15 | Code: AdeC66-15 | |||
AdeC66-16 | Paratype | Locality: 高雄甲仙六義山 | Locality: Kaohsiung, Jiaxian, Liuyi Mountain | |
Date: 2018.V.18 | Date: 2018.V.18 | |||
Collector: 周明勳 | Collector: Ming-Hsun Chou | |||
Code: AdeC66-16 | Code: AdeC66-16 | |||
AdeC66-17 | Paratype | Locality: 高雄甲仙六義山 | Locality: Kaohsiung, Jiaxian, Liuyi Mountain | |
Date: 2018.V.18 | Date: 2018.V.18 | |||
Collector: 周明勳 | Collector: Ming-Hsun Chou | |||
Code: AdeC66-17 | Code: AdeC66-17 | |||
AdeC73-4 | Paratype | Locality: 高雄甲仙六義山 | Locality: Kaohsiung, Jiaxian, Liuyi Mountain | |
Date: 2018.VI.23 | Date: 2018.VI.23 | |||
Collector: 周明勳 | Collector: Ming-Hsun Chou | |||
Code: AdeC73-4 | Code: AdeC73-4 | |||
Paratype- |
Paratype | “Formosa / Kosempo / Sauter S.V. / 9.–17. V. 08” | ||
“Zool. Mus. Berlin” | ||||
Paratype- |
Paratype | “Formosa / Kosempo / Sauter S.V. / 9.–17. V. 08” | ||
Zool. Mus. Berlin | ||||
Paratype- |
Paratype | “Formosa / Kosempo / Sauter S.V.” | ||
“17.–23. V. 08” | ||||
“Zool. Mus. Berlin” | ||||
Paratype- |
Paratype | “Formosa / Kosempo / Sauter S.V.” | ||
“2.–14. VI. 08” | ||||
“Zool. Mus. Berlin” | ||||
Paratype- |
Paratype | “Formosa / Kosempo / Sauter S.V.” | ||
“1.–5. V. 08” | ||||
“Zool. Mus. Berlin” | ||||
Paratype- |
Paratype | “Formosa / Kosempo / Sauter S.V.” | ||
“1.–5. V. 08” | ||||
“Zool. Mus. Berlin” | ||||
Paratype- |
Paratype | “Formosa / Kosempo / Sauter S.V. / 9.–17. V. 08” | ||
“Zool. Mus. Berlin” | ||||
Cylindera autumnalis | AdeC48-1 | Paratype | Locality: 屏東雙流森林遊樂區 | Locality: Pintung, Shuangliu Forest Recreation Area |
Date: 2017.VIII.10 | Date: 2017.VIII.10 | |||
Collector: 周明勳 | Collector: Ming-Hsun Chou | |||
Code: AdeC48-1 | Code: AdeC48-1 | |||
AdeC48-2 | Paratype | Locality: 屏東雙流森林遊樂區 | Locality: Pintung, Shuangliu Forest Recreation Area | |
Date: 2017.VIII.10 | Date: 2017.VIII.10 | |||
Collector: 周明勳 | Collector: Ming-Hsun Chou | |||
Code: AdeC48-2 | Code: AdeC48-2 | |||
AdeC48-4 | Paratype | Locality: 屏東雙流森林遊樂區 | Locality: Pintung, Shuangliu Forest Recreation Area | |
Date: 2017.VIII.10 | Date: 2017.VIII.10 | |||
Collector: 周明勳 | Collector: Ming-Hsun Chou | |||
Code: AdeC48-4 | Code: AdeC48-4 | |||
AdeC48-5 | Paratype | Locality: 屏東雙流森林遊樂區 | Locality: Pintung, Shuangliu Forest Recreation Area | |
Date: 2017.VIII.10 | Date: 2017.VIII.10 | |||
Collector: 周明勳 | Collector: Ming-Hsun Chou | |||
Code: AdeC48-5 | Code: AdeC48-5 | |||
AdeC48-8 | Paratype | Locality: 屏東雙流森林遊樂區 | Locality: Pintung, Shuangliu Forest Recreation Area | |
Date: 2017.VIII.11 | Date: 2017.VIII.11 | |||
Collector: 周明勳 | Collector: Ming-Hsun Chou | |||
Code: AdeC48-8 | Code: AdeC48-8 | |||
AdeC78-1 | Paratype | Locality: 屏東雙流森林遊樂區 | Locality: Pintung, Shuangliu Forest Recreation Area | |
Date: 2018.VII.21 | Date: 2018.VII.21 | |||
Collector: 周明勳 | Collector: Ming-Hsun Chou | |||
Code: AdeC78-1 | Code: AdeC78-1 | |||
AdeC78-2 | Paratype | Locality: 屏東雙流森林遊樂區 | Locality: Pintung, Shuangliu Forest Recreation Area | |
Date: 2018.VII.21 | Date: 2018.VII.21 | |||
Collector: 周明勳 | Collector: Ming-Hsun Chou | |||
Code: AdeC78-2 | Code: AdeC78-2 | |||
AdeC84-1 | Paratype | Locality: 屏東雙流森林遊樂區 | Locality: Pintung, Shuangliu Forest Recreation Area | |
Date: 2018.IX.03, | Date: 2018.IX.03, | |||
Collector: 周明勳 | Collector: Ming-Hsun Chou | |||
Code: AdeC84-1 | Code: AdeC84-1 | |||
AdeC84-2 | Paratype | Locality: 屏東雙流森林遊樂區 | Locality: Pintung, Shuangliu Forest Recreation Area | |
Date: 2018.IX.03, | Date: 2018.IX.03, | |||
Collector: 周明勳 | Collector: Ming-Hsun Chou | |||
Code: AdeC84-2 | Code: AdeC84-2 | |||
AdeC84-3 | Holotype | Locality: 屏東雙流森林遊樂區 | Locality: Pintung, Shuangliu Forest Recreation Area | |
Date: 2018.IX.03, | Date: 2018.IX.03, | |||
Collector: 周明勳 | Collector: Ming-Hsun Chou | |||
Code: AdeC84-3 | Code: AdeC84-3 |
Taiwan, Kaohsiung, Jiaxian, Liuyi Mountain.
Cylindera ooa sp. nov. can be recognized based on its elongated subapical spots and no any spot at the middle edges of elytra. This species is very similar to C. sauteri (Fig.
Head
brownish patina with blue or green luster but more brownish when alive; vertex, frons, and genae almost glabrous except two setae on canthus and anterior portion of vertex, respectively; rugae longitudinal along frons, canthi, vertex, and lateral neck, and gradually becoming transverse on genae; frons and central vertex microsculptured; clypeus brownish patina and microsculptured. Compound eyes protruding and globular. Antennae long and filiform; scape with one apical seta; 1–4 antennomeres metallic bronze; 5–11 ones dark. Mandibles testaceous with dark teeth, exceeding labrum when closed. Maxillary palps dark testaceous with metallic luster, except last two palpomeres metallic dark green. Labial palps testaceous; last palpomere metallic dark green. Labrum testaceous; anterior portion narrow and tridentate; middle tooth longer than other two in female, shorter than or equivalent to others in male; margin with 5–6 preapical and two lateral setae (Figs
Jiaxian, the type locality, is famous for taro cultivation and products. The Taiwanese pronunciation of taro is ōo-á, so it was applied as specific name.
Only known from type locality.
Habitat of C. ooa sp. nov. is similar to C. sauteri that they inhabit soil slopes with some gravels and covered by a few vegetation in or near forest. Cylindera sauteri can also be found in Jiaxian, but we did not observe them in the same habitat. Cylindera pseudocylindriformis inhabits soil slopes as well and sometimes overlaps with C. ooa sp. nov.
Holotype:
male (Fig.
Taiwan, Pintung, Shuangliu Forest Recreation Area.
Elytra are metallic brownish and marked with obvious punctures. The apical lunula is thickened in both ends (subapical corner and apical end near suture). Cylindera autumnalis sp. nov. has a different body coloration and more obvious elytral maculation than C. pseudocylindriformis (Fig.
Head
metallic bronze with weak greenish luster; genae dark metallic green; canthus with one seta; rugae longitudinal along frons, canthi, vertex, and lateral neck, and becoming transverse on genae; clypeus patina and microsculptured. Compound eyes large and protruding. Antennae slender and filiform; scape with one apical seta; 1–4 antennomeres metallic dark brown; 5–11 ones darker. Mandible yellowish pale with darker teeth, exceeding labrum when closed. Maxillary palps yellowish; last palpomere metallic dark testaceous. Labial palps yellowish; last palpomere metallic dark testaceous. Labrum testaceous; anterior margin rounded and unidentate in female; anterior margin without noticeable tooth or even concaved in male; margin with three or four preapical and two lateral setae (Figs
During the collection period in 2017 and 2018, this species was collected mostly in August to early September, especially in September. Many individuals could be found in early September when other tiger beetle adults disappeared mostly in that habitat. Thus, the specific name “autumnalis” means the autumnal tiger beetle.
Only known from type locality.
According to field observation, adults live in forest trails in late summer to autumn (late July to September). They crawl on the open ground and fly away for a short distance when being bothered, sometimes hiding in the grass or litters. The other two tiger beetle species which could be also found in the same habitat are C. cylindriformis and Therates alboobliquatus alboobliquatus Horn, 1909. However, adults of these three tiger beetles seem to appear in different seasons. Cylindera cylindriformis adults appear in early to mid-summer, and T. a. alboobliquatus was recorded mainly in mid-summer.
1 | Labrum comparatively elongated (Figs |
2 |
– | Labrum comparatively transverse (Figs |
7 |
2 | Labrum tridentate | 3 |
– | Labrum unidentate; anterior portion of labrum without obvious teeth or even concaved in male (Figs |
4 |
3 | Triangular spot on elytral middle edge present; subapical spot rounded or triangular | C. sauteri |
– | Triangular spot on elytral middle edge absent; subapical spot elongated | C. ooa sp. nov. |
4 | Labrum testaceous | 5 |
– | Labrum not testaceous | 6 |
5 | Apical lunula linear and slender in apical end near suture; metepisternum without hairs; body color dark brownish or dark iron gray; elytral maculation sometimes obscure | C. pseudocylindriformis |
– | Apical lunula thickened in apical end near suture; metepisternum with few hairs; body color metallic brownish; elytral maculation obvious | C. autumnalis sp. nov. |
6 | Middle spot triangular and about half elytral width long | C. cylindriformis |
– | Middle spot bended downward and more than half elytral width long | C. redunculata |
7 | Labrum tridentate (Fig. |
C. shirakii |
– | Labrum unidentate (Figs |
8 |
8 | Posthumeral spot absent; underside covered by dense and long white hairs; body color gray or dark gray; elytral maculation usually tiny | C. elisae reductelineata |
– | Posthumeral spot present | 9 |
9 | Body color brownish with green luster on head and pronotum; subapical spot oval or rounded and separated from apical spot; some individuals without apical spot | C. psilica |
– | Not exactly fitting above description | 10 |
10 | Middle spot long, slender and bended down; underside covered by dense and long white hairs | C. elisae formosana |
– | Elytral maculation varied, middle spot and apical lunula present, posthumeral spot ranging from tiny to large; labrum extended a little in anterior portion and with a small tooth in the middle of the extended portion; body color usually black gray but sometimes dark brownish | C. kaleea |
We acknowledge the Clinical and Industrial Genomic Application Development Service Center of National Core Facility for Biopharmaceuticals, Taiwan (MOST 107-2319-B-010-002) for sequencing. We are grateful to Bernd Jäger, the collection manager of
Tables S1–7
Data type: phylogenetic data
Explanation note: Table S1. GenSeq and accession number of vouchered and type specimens. Table S2. Pairwise distances of COI of sauteri group. Table S3. Pairwise distances of 16S rDNA of sauteri group. Table S4. Pairwise distances of 28S rDNA of sauteri group. Table S5. Pairwise distances of COI of pseudocylindriformis group. Table S6. Pairwise distances of 16S rDNA of pseudocylindriformis group. Table S7. Pairwise distances of 28S rDNA of pseudocylindriformis group.
Figures S1–8
Data type: phylogenetic data
Explanation note: Figure S1. ML tree inferred from COI of the sauteri group with ML bootstrap values (left) and BI posterior probability (right). Figure S2. ML tree inferred from 16S rDNA of the sauteri group with ML bootstrap values (left) and BI posterior probability (right). Figure S3. ML tree inferred from 28S rDNA of the sauteri group with ML bootstrap values (left) and BI posterior probability (right). Figure S4. Molecular clock inferred from the combined data of COI, 16S rDNA, and 28S rDNA of the sauteri group. Figure S5. ML tree inferred from COI of the pseudocylindriformis group with ML bootstrap values (left) and BI posterior probability (right). Figure S6. ML tree inferred from 16S rDNA of the pseudocylindriformis group with ML bootstrap values (left) and BI posterior probability (right). Figure S7 ML tree inferred from 28S rDNA of the pseudocylindriformis group with ML bootstrap values (left) and BI posterior probability (right). Figure S8. Molecular clock inferred from the combined data of COI, 16S rDNA, and 28S rDNA of the pseudocylindriformis group.