Phylogenetic Analysis of the Subfamily Ototretinae (Coleoptera: Lampyridae)
Total Page:16
File Type:pdf, Size:1020Kb
Phylogenetic analysis of the subfamily Ototretinae (Coleoptera: Lampyridae) KRISTÝNA JANISOVAa & MILADA BOCAKOVA b* "Department of Botany and Zoology, Faculty of Science, Masaryk University, Terezy Novákové 64, CZ-62100 Brno, Czech Republic h Department of Biology, Faculty of Education, Palacký University, Purkrabská 2, CZ-77140 Olomouc, Czech Republic Abstract The first phylogenetic analysis of the subfamily Ototretinae was performed. A data matrix of 42 taxa and 51 morphological characters was assembled, containing all genus - group taxa of the Ototretinae. The monophyly of the Ototretinae was supported. The preferred hypothesis, the majority rule consensus tree generated using implied weights under parsimony criterion showed Baolacus, Falsophaeopterus, Stenocladius to be the most basal splits, followed by divergence of Oculogryphus and Brachypterodrilus. All the other Ototretinae having a circular pit in posterior angles distally formed a crown clade of "higher" Ototretinae proposed here to be the tribe Ototretini. This Ototretini clade was shown to be composed of three lineages: 1. the Drilaster clade, 2. Picodrilus clade, and 3. Lamellipalpus clade. Within Drilaster clade, Emasia was recovered as sister to Drilaster + Flabellototreta clade. North American Brachylampis was shown to originate as sister to Asiatic genus Picodrilus. Within Lamellipalpus clade, Ceylanidrilus and Hydaspoides were recovered among the most basal splits. The genus Lamellipalpodes was shown to be paraphyletic with respect to the Lamellipalpus. Formerly independent subfamily Ototretadrilinae formed a sister group of (Lamellipalpus + Lamellipalpodes) + Hyperstoma clade. Ceylonese Eugeusis + Harmatelia clade was sister to Gorhamia, and all the three genera were recovered as closely related to {{Lamellipalpus -^-Lamellipalpodes) + Hyperstoma) + Ototretadrilus clade. Key words Phylogeny, Ototretinae, Lampyridae, morphology Introduction The Ototretinae belongs to the family Lampyridae, a diverse group of beetles known for their ability of bioluminescence. Lampyridae, or fireflies1, include 7 currently recognized subfamilies (Janisova &Bocakova 2013) and almost 2000 species distributed worldwide. While most fireflies use light signals in sexual selection, adults of the subfamily Ototretinae are largely non-luminous, or their light organs are small. The vast majority of ototretine genera are Oriental, with the only exception of the genus Brachylampis Van Dyke, 1939 from California. Most of the ototretines were placed in Drilidae (Wittmer 1944) on the basis of external similarities, namely the shape of pronotum and elytra. Such Drilidae included various largely elateroid genera, namely members of families as Rhagophthalmidae, Phengodidae, Omethidae, Lampyridae, Lycidae. The subfamily Ototretinae was proposed by McDermott (1964), who recognized the extrafamilial synonymy of the Oriental genus Ototreta and Japanese Drilaster (Drilidae). Many other former drilid genera were recognized as ototretine fireflies by Crowson (1972) and this concept was adopted by Lawrence and Newton (1995). Current concept of the subfamily was established by Janisova & Bocakova (2013). The phylogenetic relationships of the Ototretinae and its position within the superfamily Elateroidea have not been clarified yet. Branham &Wenzel (2001, 2003) rejected the monophyly of Ototretinae and proposed Ototretinae split. Consequently, several ototretine genera as Drilaster, Stenocladius, and Harmatelia were excluded from Lampyridae to Elateroidea incertae sedis (Branham 2010). These analyses were exclusively based on external morphological characters and consequently, suffered from parallelisms and convergences. Another recent analyses based on adult morphology (Lawrence et al. 2011) supported paraphyly of Lampyridae (incl. Ototretinae) and Ototretinae (or more exactly Ototretadrilus) were shown to be basal cantharoid splits (Lawrence et al. 2011). The monophyly of Ototretinae was rejected by a recent unpublished analysis of morphological characters of Lampyridae (Jeng 2008) who presented ototretines as basal paraphyletic grade within Lampyridae. These trees were inconsistent with analyses of large molecular datasets, which have mostly supported the monophyly of both the Lampyridae (incl. Ototretinae) and Ototretinae (Bocakova et al. 2007, Sagegami-Oba 2007, Kundrata et al. 2014). Conversely, analyses of highly variable 16S sequences rejected the monophyly of Lampyridae and Ototretinae (Suzuki 1997, Stanger-Hall 2007). The latter study, although based on 3-gene analyses, was probably affected by the exclusive use of highly variable 16S sequences (18S and coxl missing) for Stenocladius and Rhagophthalmus (Rhagophthalmidae), and consequently proposed these two genera to be members of Lampyrinae + Luciolinae + Cyphonocerinae clade. While inclusion of the Ototretinae within Lampyridae was supported by analyses of different DNA fragments (see above), the position of the Ototretinae within Lampyridae was challenged. In contrast to morphology based studies, Ototretinae were mostly recovered as a crown clade of Lampyridae (Bocakova et al. 2007, Kundrata et al. 2014). 2 The Ototretinae are fireflies of short and broad body with head partially covered by pronotum. The eyes are mostly small to medium sized, widely separated. The antennae are filiform to flabellate, extending over pronotum. Labium is transverse, some taxa present extremely enlarged terminal maxillary and labial palpomeres. Pronotum is transverse with anterior angles rounded, posterior angles triangular, projected obliquely posteriorly, often with a circular pit at base. The biology of the group is poorly known. Both sexes are sometimes fully winged (Drilaster), while larviform females were reported for Stenocladius (Ohba et al.1997). Females of many other genera are unknown and are probably brachypterous or apterous. The light production of Ototretinae is weak, or the luminescence of some genera has not been documented yet, although some taxa have abdominal luminous spots as in Harmatelia (McDermott 1965), or terminal abdominal ventrites lighter as in Brachylampis (Van Dyke 1939). In the present study, we take advantage of the recently established taxonomic framework for the subfamily Ototretinae (Janisova & Bocakova 2013; Jeng et al. 2007, 2011) and investigate the phylogeny of Ototretinae based on external morphology and male and female terminalia. To overcome the shortcomings of previous authors, taxon sampling used in this study was substantially expanded and covers all ototretine genera. Based on phylogenetic relationships obtained, the evolution of bioluminescence in adult Lampyridae was tested. Materials and methods Taxa To test the phylogenetic relationships of Ototretinae, a data matrix of 42 taxa was assembled, consisting of 32 ingroup and 10 outgroup taxa. The ingroup included species representing all Ototretinae genus-group taxa. Preferentially, the type species and one additional species were included to test the monophyly of the genera. For large genera as Drilaster several species were included representing presumed lineages of individual subgenera. The examination of specimens was mainly carried out after the dissection. A specimen of Oculogryphus was unavailable for this study and therefore, its characters were coded from the published descriptions and illustrations (Jeng et al. 2007). For the outgroup, members of other lampyrid subfamilies (Lampyrinae, Luciolinae, Photurinae, Cyphonocerinae) were examined and coded, as well as representatives of several other closely related elateroid families as Lycidae, Cantharidae, and Phengodidae. To eliminate the effect of outgroup choice, multiple outgroup approach was applied. List of taxa: ELATEROIDEA: outgroups 3 LYCIDAE Libnetis commendabilis PHENGODIDAE Phengodes plumosa CANTHARIDAE Cantharis decipiens LAMPYRIDAE: Luciolinae Hotaria parvula LAMPYRIDAE: Photurinae Photuris sp. LAMPYRIDAE: Cyphonocerinae Cyphonocerus sp. LAMPYRIDAE: Lampyrinae Lucidina biplagiata Pyrocoelia fumosa Lamprorhiza splendidula Lampyris noctiluca LAMPYRIDAE: Ototretinae Drilaster axillaris Drilaster subvittatus Drilaster medioniger Drilaster agcoensis Drilaster fuscicollis Flabellototreta fruhstorferi Flabellototreta sp. Emasia dentata Ceylanidrilus bipartitus Hydaspoides kanarensis Ototretadrilus atritarsis Ototretadrilus krombeini Gorhamia compressicornis Eugeusis ramicornis Harmatelia bilinea Lamellipalpodes sp. Lamellipalpus bombayensis Lamellipalpodes annandalei Lamellipalpodes montanus Hyperstoma marginata Hypersoma wittmeri Picodrilus dreschen Picodrilus sp. 4 Brachylampis sanguinicollis Brachypterodrilus pallidipes Brachypterodrilus atricolor Brachypterodrilus minutus Falsophaeopterus fruhsthorferi Falsophaeopterus jacobsoni Stenocladius davidis Baolacus lajoyei Oculogryphus fulvus Characters Characters applied here derive largely from external and internal morphology of adult males. Characters of females are omitted in the current analysis, as ototretine females are largely unknown, except for genera Drilaster and Stenocladius. Considering females of Drilaster are fully winged, while those of Stenocladius are larviform, scoring of morphological characters of females would result in a large number of unknown and inapplicable characters states. Similarly, larval characters were mainly omitted as larvae of most ototretine taxa are unknown. Fifty one morphological characters are included in the current analysis (Table 1). Of these, 11 characters refer to external morphology, while the largest