Research Article |
Corresponding author: Ladislav Bocak ( ladislav.bocak@upol.cz ) Academic editor: Hume Douglas
© 2016 Matej Bocek, Ladislav Bocak.
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Citation:
Bocek M, Bocak L (2016) Species limits in polymorphic mimetic Eniclases net-winged beetles from New Guinean mountains (Coleoptera, Lycidae). ZooKeys 593: 15-35. https://doi.org/10.3897/zookeys.593.7728
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Species delimitation was compared in a group of closely related lineages of aposematically colored Eniclases (Coleoptera, Lycidae) using morphology, genetic distances, and Bayesian implementation of the Poisson Tree Processes model. A high diversity of net-winged beetles was found in previously unsampled regions of New Guinea and ten new species are described: Eniclases bicolor sp. n., E. bokondinensis sp. n., E. brancuccii sp. n., E. elelimensis sp. n., E. infuscatus sp. n., E. niger sp. n., E. pseudoapertus sp. n., E. pseudoluteolus sp. n., E. tikapurensis sp. n., and E. variabilis sp. n. Different levels of genetic and morphological diversification were identified in various sister-species pairs. As a result, both morphological and molecular analyses are used to delimit species. Sister-species with uncorrected pairwise genetic divergence as low as 0.45% were morphologically distinct not only in color pattern, but also in the relative size of eyes. Conversely, differences in color pattern regardless of their magnitude did not necessarily indicate genetic distance and intraspecific mimicry polymorphism was common. Additionally, genetic divergence without morphological differentiation was detected in one sister-species pair. Low dispersal propensity, diverse mimicry patterns, and mimetic polymorphism resulted in complex diversification of Eniclases and uncertain species delimitation in recently diversified lineages.
Aposematism, bPTP model, Coleoptera , cox1 mtDNA, genetic distance, morphology, new species, species delimitation
The Papuan beetle fauna remains one of the most under-investigated despite high species richness in the Oceanian region and a long history of taxonomic research in Papua (e.g.
Most Papuan net-winged beetles belong to genera known from Australia (
A taxonomic study based on material representing Eniclases from the western part of the island, mainly from the Central Mts, is presented. The aim was to compare species delimitations inferred from genetic distances (barcoding approach;
In total, 81 specimens of Eniclases from the western part of New Guinea: the Central, Cyclops and Arfak Mts. were kept in -20 °C until DNA extraction. Each specimen was given a voucher number (Figs
1 Phylogenetic tree of Eniclases inferred from the maximum likelihood optimality criterion; a basal part of outgroups omitted. The numbers at branches show bootstrap support greater than 50%, genetic divergence within respective putative species and posterior probabilities inferred from the bPTP model 2 Dated tree produced using Bayesian inference.
Sequences were edited using the Sequencher 4.8 software package (Gene Codes Corp.) and combined with homologous sequences of 25 outgroup taxa representing Cautirina and Metriorrhynchina (all sequences taken from GenBank). The length invariable cox1 mtDNA fragment was aligned using ClustalX 2.1 (
The genetic intra- and interspecific differentiation among whole-fragment sequences was estimated using Kimura 2-parameter genetic distances in MEGA6 (
Morphological characters were observed for all sequenced specimens: measurements of the body size, maximum diameter of eyes in the lateral view, the minimum interocular distance in the frontal part of cranium, color patterns of the pronotum and elytra, shape of pronotum and antennae, and structure of the elytral costae. Photographs were taken using a binocular microscope Olympus SZX-16 and were assembled in Helicon Focus 6 (www.heliconsoft.com). Due to previously reported uniformity of the genitalia of both sexes (
DEIM Deutsches Entomologisches Institute, Müncheberg, Germany
MHNP Muséum national d’Histoire naturelle, Paris, France
LMBC Voucher collection, Department of Zoology, UP Olomouc, Czech Republic
The 1101 bp fragment of mtDNA was sequenced for 81 individuals of Eniclases from western New Guinea. The DNA fragment consisted of 782 base pairs (bp)cox1 mtDNA, 59 bp tRNA-Leu, and 260 bpcox2 mtDNA. We identified 38 unique haplotypes and the Kimura-2-parameter genetic distances among Eniclases sequences spanned 0.09–14.31%. The maximum likelihood analysis produced the tree in Fig.
The genetic divergence between all haplotypes was evaluated and the highest densities were between 0.0–2.0% and 9.0–14% (Fig.
3 The positions, coordinates and elevations of sampled localities in the Central Mountains of New Guinea 4 Density plots of genetic distances of all Eniclases samples 5 Density plots of intra- and interspecific genetic distances between pairs of closely related species of Eniclases (E. infuscatus and E. bicolor; E. tikapurensis and Eniclases sp. A; E. variabilis, E. elelimensis and E. bokondinensis; E. niger and E. similis).
Furthermore, putative species were identified using genetic distance and the phylogenetic tree. The pairwise differences among cox1 mtDNA sequences merged haplotypes in 9 clusters when the threshold 3% was applied. The inferred clusters merged E. infuscatus and E. bicolor, E. tikapurensis + Eniclases sp. A, the clade E. elelimensis + E. bokondinensis + E. variabilis and the pair E. niger + E. similis (Fig.
Fourteen species were identified in the sequenced material, including ten new to science and described in the Taxonomy section. The delimitation of species was based on morphological characters (the size of eyes, shape of male antennae and coloration), genetic distance, and delimitations of putative species inferred from the bPTP model.
Eniclases Waterhouse, 1879: 66.
Lycus luteolus Waterhouse, 1878 by monotypy.
Eniclases is similar to Trichalus Waterhouse, 1877 and they share a small to medium sized, dorso-ventrally flattened body; a characteristic shape of a pronotum with acutely projecting posterior angles and a hump in a posterior third of a pronotal margin; nine elytral costae in the humeral part of elytra (four robust primary costae and five weak secondary costae) and a shortened primary costa 1 (Figs
Habitus of Eniclases: 6 E. divaricatus, male 7 E. pseudoapertus sp. n., male 8 E. apertus, male 9 E. tikapurensis sp. n., male 10 E. bicolor sp. n., female 11 E. infuscatus sp. n., female 12 E. brancuccii sp. n., female 13, 14 E. similis, male 15, 16 E. niger sp. n., male 17 E. bokondinensis sp. n., female. Scale bars: 2 mm.
The shape of the pronotum, shortened elytral costa one, and shape of male genitalia (Figs
Basal antennomeres of (Figs 30–42): 30 E. apertus, male 31 E. bicolor sp. n., female 32 E. bokondinensis sp. n., female 33 E. brancuccii sp. n., male 34 E. divaricatus, male 35 E. infuscatus sp. n., female 36 E. pseudoluteolus, male 37 E. similis, male 38 E. variabilis sp. n., male 39 E. elelimensis, male 40 E. niger sp. n., female 41 E. tikapurensis, male 42 E. pseudoapertus sp. n., male. Male genitalia, ventral view (Figs 43–50): 43 E. pseudoapertus sp. n. 44 E. divaricatus 45 E. tikapurensis sp. n. 46 E. brancuccii sp. n. 47 E. variabilis sp. n. 48 E. pseudoluteolus sp. n. 49 E. niger sp. n. 50 E. similis. Scale bars: 0.5 mm.
Holotype. Male (Voucher number BM0080), Indonesia, Irian Jaya, Arfak Mts., Maibri village, 1570 m, Nov.–Dec. 1991 (LMBC).
Eniclases pseudoapertus resembles E. apertus Pic, 1923 in the small body and black coloration (Fig.
Measurements of Eniclases spp. (all measurements in mm, n.a. – not available).
Body length | Width humeri | Pronotum | Eye diameter/distance | |||
---|---|---|---|---|---|---|
length | width | male | female | |||
E. pseudoapertus | 6.3 | 1.6 | 0.75 | 1.2 | 1.4 | n.a. |
E. divaricatus | 8.8–9.7 | 2.1–2.3 | 1.2–1.3 | 1.7–1.7 | 0.92–0.96 | 0.80–0.87 |
E. pseudoluteolus | 9.3 | 2.3 | 1.15 | 1.6 | 0.9 | n.a. |
E. apertus | 5.8–6.9 | 1.4–1.7 | 0.9 | 1.25 | 1.15–1.17 | |
E. tikapurensis | 9.5–11.1 | 2.0–2.5 | 1.1–1.3 | 1.4–1.7 | 1.11–1.40 | 0.92–1.06 |
E. bicolor | 10.3 | 2.4 | 1.4 | 1.7 | n.a. | 0.71–0.74 |
E. infuscatus | 12.1 | 2.5 | 1.25 | 1.6 | n.a. | 0.79–0.84 |
E. brancuccii | 7.6–8.0 | 1.8–1.9 | 1.0–1.1 | 7.5–8.0 | 1.00 | 0.84–0.91 |
E. bokondinensis | 9.2 | 2.05 | 1.0 | 1.35 | n.a. | 0.72–0.82 |
E. elelimensis | 6.9–8.1 | 1.5–1.9 | 0.9–1.1 | 1.3–1.4 | n.a. | 0.78–0.89 |
E. variabilis | 6.6–8.2 | 1.6–2.0 | 0.1–1.1 | 1.1–1.35 | 0.83–0.95 | 0.70–0.85 |
E. niger | 9.2–11.6 | 2.2–2.8 | 1.3–1.6 | 9.0–11.5 | 1.17–1.28 | 0.89 |
E. similis | 7.5–9.7 | 1.9–2.3 | 1.1–1.4 | 1.8–1.8 | 1.02–1.15 | 0.89 |
Male. Body length 6.3 mm, uniformly dark colored, only trochanters and bases of femora light brown (Fig.
Indonesia, Arfak Mts.
The specific name refers to similarity with E. apertus.
Trichalus (Trichalolus) divaricatus Pic, 1921: 10.
Lectotype. Female, New Guinea, Humboldt Bay, Doherty lgt., coll. Pic (MHNP). Other material examined. 4 males, 2 females (BM0001–2, 9, 15–17), Indonesia, Irian Jaya, Sentani, Cyclops Mts., 300 m, Nov.–Dec. 1991; female (BM0057), Indonesia, Irian Jaya, Elelim, path to Apalapsili, 600 m, Nov.–Dec. 1991 (LMBC).
Eniclases divaricatus is the only Papuan species with the bicolored elytra and flabellate male antennae (Figs
Male. Body length 8.8–9.7 mm. Head, thorax, legs, and humeri yellow to orange, antennae except basal part, abdomen, and most of elytra dark colored. Head with moderately large, hemispherically prominent eyes, their diameter 0.92–0.96 times minimum interocular distance Antennae flabellate, lamella of antennomere 3 slightly longer than the body of antennomere, other lamellae similar (Fig.
Central North New Guinea.
Holotype. Female (BM0050), Indonesia, Irian Jaya, Bokondini, 1300 m, Nov.–Dec. 1991 (LMBC). Paratype. Female (BM0062), Indonesia, Irian Jaya, Elelim, path to Apalapsili, 600 m, Nov.–Dec. 1991 (LMBC).
Eniclases infuscatus has a unique color pattern among western Papuan Eniclases. The upper part of the body is yellow to orange and only tips of elytra and the posterior part of the lateral margins are infuscate. This species partly resembles in the coloration E. tikapurensis, which is slender and pale colored (Figs
Female. Body length 12.1 mm, robust. Head brown, abdomen, meso- and metathorax dark colored, most of legs similarly colored, only trochanters and basal half of femora light brown; pronotum and elytra yellow to orange, only tips and posterior margins of elytra infuscate, transition between dark and bright parts of elytra gradual (Fig.
New Guinea, Bokondini region.
The specific name refers to blackened edge of the apical part of elytra.
Holotype. Female (BM0046), Indonesia, Irian Jaya, Elelim, path to Apalapsili, 600 m, Nov.–Dec. 1991 (LMBC). Paratypes. 2 females (BM0045, 47), same locality data as the holotype (LMBC).
Eniclases bicolor resembles some forms of E. similis from the Cyclops Mts. and differs in a higher contrast between light colored costae and dark cells in a transitional area between the dark and light parts of their elytra (Fig.
Female. Body length 10.3 mm, robust. Head, basal part of antennae, pro- and mesothorax, basal half of elytra and legs yellow to light orange, apical half of antennae, metathorax, half of elytra and abdomen dark, transition between dark and bright parts abrupt(Fig.
New Guinea, Elelim region.
The specific name refers to the coloration of elytra.
Holotype. Male (BM0039), Indonesia, Irian Jaya, Yiwika, N of Wamena, 2000 m, Nov.–Dec. 1991 (LMBC). Paratypes. 3 males, 2 females (BM0040–44), Indonesia, Irian Jaya, Tikapura village, 2200 m, Nov.–Dec. 1991 (LMBC).
Eniclases tikapurensis resembles in general appearance E. papuensis Bocak & Bocakova, 1991 from the Panai Lake area approximately 250 km west of Yiwika. Both species are characteristic in pale hue of the yellow upper part (Fig.
Male. Body length 9.5–11.1 mm, slender (Table
New Guinea, Upper Baliem Valley.
The specific name refers to the type locality, the village Tikapura, north of Tagime.
The genetically distant population from Bokondini is a sister to E. tikapurensis, but does not differ in any morphological character. As their delimitation would be based only on mtDNA sequence and further information on nuclear markers and geographical distribution is needed for these two putative cryptic species, we postpone the formal description of the population from Bokondini. The sequenced specimens representing the Bokondini population are designated as Eniclases sp. A. in Fig.
Holotype. Male (BM0006), Indonesia, Irian Jaya, Sentani, Cyclops Mts., 300 m, Nov.–Dec. 1991 (LMBC). Paratypes. 3 females (BM0005, 0007, 00010), the same data as the holotype (LMBC).
Eniclases brancuccii resembles in color pattern three species: E. elelimensis, E. niger, and E. variabilis. The last two of them are polymorphic and only some individuals share the color pattern with E. brancuccii (Figs
Male. Body length 7.6–8.0 mm, robust, head, antennae, thorax, elytra, and abdomen dark brown to black, pronotum, scutellum, and basal parts of femora yellow to orange, apical parts of femora, tibiae, and tarsi dark brown. Head with small, hemispherically prominent eyes, their diameter equals minimum interocular distance, antennae flat, slender, acutely serrate, apical process of antennomere 3 about half length of its body, further antennomeres similar in shape. Pronotum transverse, with apparent bulge in basal third, almost parallel-sided between bulge and posterior angles, elytra with weak but regular secondary costae and mostly regular, quadrate, small cells.
New Guinea, Cyclops Mountains.
The specific name ‘brancuccii’ is proposed in honor of the late Michel Brancucci, a specialist in Dytiscidae and Cantharidae.
Holotype. Female (BM0056), Indonesia, Irian Jaya, Elelim, path to Apalapsili, 600 m, Nov.–Dec. 1991 (LMBC). Paratypes. 2 females (BM0051–52), the same data as the holotype (LMBC).
Eniclases elelimensis differs from E. brancuccii in slightly smaller eyes (Table
Male. Body length 6.9–8.1 mm, robust, head, antennae, thorax, elytra, and abdomen dark brown to black, pronotum and femora yellow to light orange, apical part of femora, tibiae, and tarsi dark brown. Head with small, hemispherically prominent eyes, their diameter equals minimum interocular distance, antennae flat, slender, acutely serrate, apical process of antennomere 3 about half length of its body, further antennomeres similar in shape. Pronotum transverse, with apparent bulge in basal third, almost parallel-sided between bulge and posterior angles, elytra with weak but regular secondary costae and mostly regular, quadrate, small cells.
New Guinea, Elelim region.
The specific name refers to the type locality.
E. versicolor Kleine, 1926 from an unspecified locality in New Guinea was studied (Holotype, male, ‘Neuguinea, Coll. Kraatz’ deposited in DEIM). Eniclases versicolor is similar in general appearance, but differs in large male eyes. The female specimen of E. versicolor from the Jayapura district cited by
Holotype. Female (BM0095), Indonesia, Irian Jaya, Bokondini, 1900 m, Nov.–Dec. 1991 (LMBC). Paratypes. 2 females (BM0092, 94), the same data as the holotype (LMBC).
Eniclases bokondinensis has a characteristic combination of the black pronotum and light yellow elytra with dark colored apex (Figs
Female. Body length 9.2 mm, head, antennae, thorax, and abdomen dark brown to black, elytra pale yellow in humeral half, gradually infuscate to apex (Figs
New Guinea, Bokondini region.
The specific name refers to the type locality.
Holotype. Male (BM0054), Indonesia, Irian Jaya, Elelim, path to Apalapsili, 600 m, Nov.–Dec. 1991 (LMBC). Paratypes. 1 male, 3 females (BM0048–49, 53, 55), same data as the holotype; 7 males, 8 females (BM0025–32, 34–36, 86, 88, 90–91), Indonesia, Irian Jaya, Bokondini, 1300 m, Nov.–Dec. 1991; 4 males, female (BM0063–67), Indonesia, Irian Jaya, Dombomi, Lower Pass valley, 1200 m; 2 males (BM0008, 12), Indonesia, Irian Jaya, Sentani, Cyclops Mts., 300 m, Nov.–Dec. 1991 (LMBC).
Eniclases variabilis is a widespread, highly polymorphic species and resembles in general appearance several distinct, sympatric mimetic types. The color forms are illustrated in Figs
Male. Body length 6.6–8.2 mm. Head, antennae, thorax, and abdomen dark black, elytra orange yellow in humeral third, rest of elytra black, transitional zone between bright and dark part of elytra is narrow (Figs
Central North New Guinea.
The specific name refers to exceptional variability in coloration.
Eniclases variabilis can be differently colored in various localities. Generally, the dark colored specimens (Fig.
Holotype. Male (BM0084), Indonesia, Irian Jaya, Maibri vill., Arfak Mts., 1600 m, Nov.–Dec. 1991 (LMBC).
Eniclases pseudoluteolus belongs to the group of uniformly yellow species which additionally includes E. luteolus Waterhouse, 1878, E. nigriceps Bocak & Bocakova, 1991, E. fuscicornis Bocak & Bocakova, 1991, and E. pallidus Bocak & Bocakova, 1991. Most of them have large eyes (
Male. Body length 9.3 mm, head, apical antennomeres, thorax, and abdomen dark brown to black, pronotum and elytra yellow, trochanters brown, rest of legs black. Head with small, hemispherically prominent eyes, their diameter 0.90 interocular distance, antennae flat, acutely serrate, antennomere 3 triangular, wide, its apical process short (Fig.
New Guinea, Arfak Mts.
The specific name refers to the similarity with E. luteolus.
Holotype. Male (BM0059), Indonesia, Irian Jaya, Elelim, path to Apalapsili, 600 m (LMBC). Paratypes. 3 males (BM0058, 60–61), same data as the holotype; 2 males, 1 female (BM0033, 87, 89), Indonesia, Irian Jaya, Bokondini, 1300 m, Nov.–Dec. 1991 (LMBC).
Eniclases niger is polymorphic in coloration and can be uniformly black or can have the brightly colored pronotum and scutellum (Figs
Male. Body length 9.2–11.6 mm (Table
New Guinea, Central Mountains.
The specific name refers to body coloration.
Eniclases niger has two forms (Figs
Eniclases similis Bocak & Bocakova, 1991: 210.
10 males, 2 females (BM0003–4, 11, 13–14, 19–24, 37), Indonesia, Irian Jaya, Sentani, Cyclops Mts., 300 m, Nov.–Dec. 1991 (LMBC).
Eniclases similis differs from the similarly colored individuals of E. divaricatus in large eyes (Table
Male. Body length 7.5–9.7 mm, pronotum, humeral part of elytra, and legs yellow to orange, metathorax, abdomen, apical part of elytra, and sometimes antennae dark brown to black (Figs
New Guinea Highlands.
Eniclases similis has two extreme forms in the extent of the bright part of elytra (Figs
The taxonomy of Eniclases has been based solely on the morphological species concept, which depends on the presence of identifiable diagnostic traits (
Morphological and DNA sequence diversification was investigated in a clade of 14 Eniclases net-winged beetles from the western part of New Guinea, delimited as separate species using mtDNA haplotypes, morphological characters and biogeography (
A much higher degree of uncertainty was found in pairs of closely related terminals, which were refused as putative species by various methods (Fig.
The pair of E. infuscatus and E. bicolor represents sister species which differ in coloration (Figs
Similarly, E. bokondinensis and E. elelimensis represent genetically close species with different color patterns (Figs
Eniclases variabilis is a sister to the E. bokondinensis + E. elelimensis clade and was identified as a separate entity using the bPTP model. Other methods merged this species with its sister clade (genetic distance, Fig.
The clade of E. similis + E. niger was merged into a single putative species by all DNA based analyses, but they can be identified by morphology and color patterns. Eniclases niger has large eyes (diameter/distance ratio 1.17–1.28) and E. similis has smaller eyes (1.02–1.15). We suppose that the daytime or evening, eventually night activity of respective species might be the reason for observed morphological differentiation. Additionally, these species belong to different mimetic complexes. E. niger is black colored (Fig.
The clade of E. tikapurensis and Eniclases sp. A split in two subclades, which do not differ in morphology, but they are genetically distant. The levels of DNA distances between E. tikapurensis and Eniclases sp. A do not agree with the geographical distance of respective localities, when higher differentiation was found between populations from Bokondini and Tikapura (13 km apart) than between localities lying at the rim of the Baliem valley (Yiwika and Tikapura, 35 km apart). The observed genetic differentiation surpasses some cases when separate morphologically divergent sister species are delimited. Due to limited information we postpone formal description of the putative species from Bokondini.
Eniclases are variable in coloration (Figs
We are sincerely grateful to R. Bilkova for technical assistance and to colleagues who provided us with the material for this study. Timothy C. Bray critically read the MS prior to its submission.
This work was supported by the Czech Science Foundation (P506/11/1757) and the Palacky University (PrF2015-018).