A historical biogeography of megadiverse Sericini-another story “out of Africa”?

Tetraserica Ahrens, 2004 of continental Southeast Asia: new records, new species, and an updated key to species (Coleoptera: Scarabaeidae: Sericinae: Sericini)

An update to the taxonomy and distribution of species of Tetraserica Ahrens, 2004 (Coleoptera: Scarabaeidae) is given. We present new records of 36 taxa and describe 13 new species from continental Southeast Asia: Tetraserica bartolozzii Ahrens, new species, T. bankrang Ahrens, new species, T. sraeken Ahrens, new species, T. yongbelar Ahrens, new species, T. hubleyi Ahrens, new species, T. hornburgi Ahrens, new species, T. khemoi Ahrens, new species, T. weigeli Ahrens, new species, T. yucheni Liu, Li & Ahrens, new species, T. fabriziae Liu, Li & Ahrens, new species, T. gialaiensis Pham & Ahrens, new species, T. phamanhi Pham & Ahrens, new species, and T. semikontumensis Pham & Ahrens, new species. The male genitalia of the new species are illustrated and diagnostic characters to related species are given. The key to species of continental Southeast Asia is updated.

New species of the tribe Sericini Kirby, 1837 from China, with further updates on their taxonomy and distribution (Coleoptera: Scarabaeidae: Sericinae)

Fifteen new species of Sericini are described from China, including Gastroserica (s. str.) mayunshui Zhao & Ahrens, new species, Pachyserica albopunctata Zhao & Ahrens, new species, P. dongnanensis Zhao & Ahrens, new species, P. jianfengensis Zhao & Ahrens, new species, Serica (s. l.) caiyiyiae Zhao & Ahrens, new species, S. (s. l.) babaoshanensis Zhao & Ahrens, new species, S. (s. l.) jicaiyanae Zhao & Ahrens, new species, S. (s. l.) zhangyaonani Zhao & Ahrens, new species, S. (s. l.) longidentata Zhao & Ahrens, new species, S. (s. l.) callosericoides Zhao & Ahrens, new species, S. (Taiwanoserica) liboyani Zhao & Ahrens, new species, S. (T.) yangzaichuni Zhao & Ahrens, new species, Maladera zhanchaoi Zhao & Ahrens, new species M. parabikouensis Zhao & Ahrens, new species and M. shikengkongensis Zhao & Ahrens, new species. Maladera juxianensis Ahrens, Fabrizi & Liu, 2021 was recognized as a junior synonym of M. aureola (Murayama, 1938). Additional collecting data for 32 other sericine species is presented.

A new species and new records of Sericini chafers from the Lower Gangetic Plains in India (Coleoptera: Scarabaeidae: Sericinae)

Here, we investigated the diversity of Sericini in the faunistically rather unknown Lower Gangetic plains in North India, based on material from the collection of the Zoological Survey of India. We discovered one new species from West Bengal, Maladerakolkataensis Bhunia, Gupta, Sarkar & Ahrens, and provide further records of an additional 23 species belonging to five genera from the lowlands of the states Bihar and West Bengal. Out of these, 21 species represent new state records: 12 for Bihar and nine for West Bengal. All recorded species are briefly documented by diagnostic illustrations.

Updates on the taxonomy and distribution of Gastroserica Brenske, 1897, Microserica Brenske, 1894, and Moronoserica Ahrens, Lukic & Liu, 2023 (Coleoptera: Scarabaeidae: Sericinae: Sericini)

A short update on the taxonomy of Gastroserica Brenske, 1897 is given. Two new species of the subgenus Helioserica Ahrens, Lukic & Liu, 2023, and one new species of the nominotypical subgenus are described: Gastroserica (H.) kachin Ahrens & Pham, new species (from Myanmar), G. (H.) horii Ahrens & Pham, new species, and G. (G.) muongphangensis Ahrens & Pham, new species (both from Vietnam). One name is synonymized: Gastroserica (G.) wenzhui Liu & Ahrens, 2014 (= Gastroserica skalei Ahrens & Fabrizi, 2018, new synonymy). Additional new records of the recently revised Microserica Brenske, 1894, and Moronoserica Ahrens, Lukic & Liu, 2023 as well as of Gastroserica are given. The diagnostic characters of the new taxa are illustrated. A corrective note for Ahrens et al. (2023) is also given, regarding the omitted but previously published synonymy of Microserica pusilla (Thunberg, 1818) (= Microserica compressipes (Weidemann, 1823)).

Local stochastics and ecoclimatic situation shape phytophagous chafer assemblage composition

Very little is known about factors determining the assemblage structure of megadiverse polyphagous-herbivore scarab chafers in the tropics (Coleoptera: Scarabaeidae). Here, we examined the composition of Sri Lankan chafer assemblages and investigated whether it is influenced more by the general ecoclimatic situation, macrohabitat, or indetermined stochastic biotic and abiotic factors of each locality. We also explored the influence of the latter on separate lineages and general body size. Based on dedicated field surveys conducted during the dry and wet seasons, we examined 4847 chafer individuals of 105 species sampled using multiple UV-light traps in 11 localities covering different forest types and altitudinal zones. Assemblages were assessed for compositional similarity, species diversity, and abundance within four major eco-spatial partitions: forest types, elevational zones, localities, and macrohabitats. Our results revealed that assemblages were shaped mainly by locality stochastics (i.e., multi-factor ensemble of all biotic and abiotic environmental conditions at local scale), and to a minor extent by ecoclimatic conditions. Macrohabitat had little effect on the assemblage composition. This was true for the entire chafer assemblage as well as for all single lineages or different body size classes. However, in medium and large species the contrasts between localities were less pronounced, which was not the case for individual lineages of the assemblage. Contrasts of assemblage similarity between localities were much more evident than those for forest types and elevation zones. Significant correlation between species composition and geographic distance was found only for the assemblage of small-bodied specimens. Seasonal change (dry-wet) in species composition was minor and only measurable in a few localities. The strong turnover between examined localities corroborates with the high degree of endemism in many phytophagous chafers, particularly in Sericini. Connected with their hypothetic poor habitat specificity and polyphagy, this might also explain why so many chafer crop pests in the Asian tropics are endemics.

Phylogenomics and historical biogeography of the cleptoparasitic bee genus Nomada (Hymenoptera: Apidae) using ultraconserved elements

The genus Nomada Scopoli (Hymenoptera: Apidae) is the largest genus of brood parasitic bees with nearly 800 species found across the globe and in nearly all biogeographic realms except Antarctica. There is no previous molecular phylogeny focused on Nomada despite their high species abundance nor is there an existing comprehensive biogeography for the genus. Using ultraconserved element (UCE) phylogenomic data, we constructed the first molecular phylogeny for the genus Nomada and tested the monophyly of 16 morphologically established species groups. We also estimated divergence dates using fossil calibration points and inferred the origin and of this genus around the globe. Our phylogeny recovered 14 of the 16 previously established species groups as monophyletic. The superba and ruficornis groups, however, were recovered as non-monophyletic and need to be re-evaluated using morphology. Divergence dating and historic biogeographic analyses performed on the phylogenetic reconstruction indicates that Nomada most likely originated in the Holarctic ∼65 Mya. Geodispersal into the southern hemisphere occurred three times; once during the Eocene into the Afrotropics, once during the Oligocene into the Neotropics, and once during the Miocene into Australasia. Geodispersal across the Holarctic was most frequent and occurred repeatedly throughout the Cenozoic era, using the De Geer, Thulean, and the Bering Land Bridges. This is the first instance of a bee using both the Thulean and De Geer land bridges and has implications of how early bee species dispersed throughout the Palearctic in the late Cretaceous and early Paleogene.

Comparative analysis of morphospace of Neotropical Sericini (Coleoptera: Scarabaeidae): disparity in the light of species diversity and activity patterns

The striking diversity among herbivorous Scarabaeoidea is still poorly understood. Therefore, we compare in these work linear measurements of body features of Neotropical and Old World linages of Sericini chafers to uncover patterns possibly linked to foraging behavior (day or night activity) or to the success of their diversification in terms of diversity. If diversity in Sericini chafers would be linked to morphological disparity, we would expect in the much less diverse Neotropical lineage a very clear drop of morphological disparity. Comparing the two major sister clades, Old World and Neotropical Sericini, in terms of their disparity and diversity, the here elaborated distance data do not support the hypothesis that morphological disparity could be a driver for the diversity of Sericini in the Old World. The influence of the metacoxal length on morphological disparity appears to represent a possible key for a better understanding of the evolution of Sericini in the Neotropical region (including their lower diversity) and answers the question of why they are so much less diverse than their sister lineage in the Old World. The increasing length of the metacoxal plate appears to be a result of the presence of a secondary metacoxal joint in Old World Sericini, which has a crucial impact on hind leg mobility and digging behavior. General body shape and single morphological characters appear under similar general evolutionary pressure: high morphometric disparity between nocturnal and diurnal Neotropical species was also corroborated by disparity estimated from discrete morphological characters.

Excluding spatial sampling bias does not eliminate oversplitting in DNA-based species delimitation analyses

DNA barcoding and DNA-based species delimitation are major tools in DNA taxonomy. Sampling has been a central debate in this context, because the geographical composition of samples affects the accuracy and performance of DNA barcoding. Performance of complex DNA-based species delimitation is to be tested under simpler conditions in absence of geographic sampling bias. Here, we present an empirical dataset sampled from a single locality in a Southeast-Asian biodiversity hotspot (Laos: Phou Pan mountain). We investigate the performance of various species delimitation approaches on a megadiverse assemblage of herbivorous chafer beetles (Coleoptera: Scarabaeidae) to infer whether species delimitation suffers in the same way from exaggerate infraspecific variation despite the lack of geographic genetic variation that led to inconsistencies between entities from DNA-based and morphology-based species inference in previous studies. For this purpose, a 658 bp fragment of the mitochondrial cytochrome c oxidase subunit 1 (cox1) was analyzed for a total of 186 individuals of 56 morphospecies. Tree-based and distance-based species delimitation methods were used. All approaches showed a rather limited match ratio (max. 77%) with morphospecies. Poisson tree process (PTP) and statistical parsimony network analysis (TCS) prevailingly over-splitted morphospecies, while 3% clustering and Automatic Barcode Gap Discovery (ABGD) also lumped several species into one entity. ABGD revealed the highest congruence between molecular operational taxonomic units (MOTUs) and morphospecies. Disagreements between morphospecies and MOTUs have to be explained by historically acquired geographic genetic differentiation, incomplete lineage sorting, and hybridization. The study once again highlights how important morphology still is in order to correctly interpret the results of molecular species delimitation.

Taxonomic review on the Trioserica Moser, 1922 species of China (Coleoptera: Scarabaeidae: Melolonthinae: Sericini)

In the present study the taxonomy of the species of the genus Trioserica Moser, 1922 from China is revised. We recorded so far six valid species, of which five resulted to be new to science: Trioserica cangyuanensis Ahrens, Liu Fabrizi, new species, T. daweishana Ahrens, Liu Fabrizi, new species, T. dinghushanica Ahrens, Liu Fabrizi, new species, T. lilongensis Ahrens, Liu Fabrizi, new species, and T. shiyiduiensis Ahrens, Liu Fabrizi, new species. The habitus and male genitalia of the species are illustrated and maps of their known distribution are shown.

Unexpected diversity of Hyboserica chafers in South African forest remnants: cladistic analysis, new species and the new genus Leoserica (Coleoptera: Scarabaeidae: Melolonthinae)

A taxonomic revision of Hyboserica uncovers an unexpected diversity of species from Southern African forest remnants. The work results in the description of a new genus, Leoserica gen. nov., a new combination, a new synonymy and 32 new species are described. The lectotypes of Serica capensis and Triodonta caffra are designated. The habitus and male genitalia of all revised species are illustrated. A species distribution map and an identification key to the species are provided. Phylogenetic analysis reveals a deep split into one very diverse eastern clade that is distributed north to Zimbabwe, and one western clade that is restricted to the fynbos of the Cape Region.

Molecular phylogeny reveals the gradual evolutionary transition to soft-bodiedness in click-beetles and identifies sub-Saharan Africa as a cradle of diversity for Drilini (Coleoptera: Elateridae)

Drilini are soft-bodied predatory click-beetles (Elateridae: Agrypninae) with incompletely metamorphosed females. Due to divergent morphology, their classification has been contentious. We present the first densely sampled molecular phylogeny of Drilini based on nuclear and mitochondrial markers. Altogether, 44 species, representing all genera, were analysed using maximum likelihood and the Bayesian approach. Molecular analyses recovered five major clades that were also well supported by morphology. Afrotropical lineages mark deep splits. Most Palearctic species belong to a terminal clade. A few species of the predominantly Afrotropical Selasia are distributed from Arabia up to the Himalayas and Thailand. The origin of Drilini is dated to the Late Eocene (~35.5 Mya) and rapid radiation is identified from the Eocene/Oligocene to the Middle Miocene. We describe the gradual transformation of male morphological traits, e.g. the level of sclerotization, structure of mouthparts, loss of the thoracic interlocking mechanism, shortened elytra and expanded larviform abdomen. Five new genera, Austroselasia, Habeshaselasia, Illubaboria, Malacodrilus and Mashaselasia are proposed. Latoselasia, previously a subgenus of Wittmerselasia, is elevated to the genus rank. Five new species, Habeshaselasia nekemtensis, H. illubaborensis, Illubaboria bicolor, Malacodrilus hajeki and Mashaselasia aethiopica are described.

A monograph on the genus Tetraserica from the Indochinese region (Coleoptera, Scarabaeidae, Sericini)

In this monograph on the Indochinese species of Tetraserica Ahrens, 2004 all species distributed in Thailand, Laos, Vietnam, Cambodia, Myanmar, and mainland Malaysia are covered as well as those of the Indian province Mizoram. From this revision, the following new combinations result: Tetrasericagressitti (Frey, 1972), comb. n., T.laotica (Frey, 1972), comb. n., T.satura (Brenske, 1898), comb. n., T.sejugata (Brenske, 1898), comb. n., T.siantarensis (Moser, 1922), comb. n., T.spinicrus (Frey, 1972), comb. n., T.vietnamensis (Frey, 1969), comb. n., and T.wapiensis (Frey, 1972), comb. n. Two new synonyms were found: Tetrasericamidoriae Kobayashi, 2017 (syn. n.) = T.laotica (Frey, 1972); T.graciliforceps Liu et al. 2014 (syn. n.) = T.satura (Brenske, 1898). The lectotypes of Tetrasericagestroi (Brenske, 1898), T.miniatula (Moser, 1915), and T.siantarensis (Moser, 1922) are designated. 116 Tetraserica species were recorded from Indochina, among which 88 new species are described: Tetrasericaallochangshouensis sp. n., T.allomengeana sp. n., T.allosejugata sp. n., T.angkorthomensis sp. n., T.angkorwatensis sp. n., T.appendiculata sp. n., T.auriculata sp. n., T.bachmaensis sp. n., T.banhuaipoensis sp. n., T.bansanpakiana sp. n., T.bolavensensis sp. n., T.breviforceps sp. n., T.cattienensis sp. n., T.champassakana sp. n., T.constanti sp. n., T.cucphongensis sp. n., T.curviforceps sp. n., T.desalvazzai sp. n., T.doiphukhaensis sp. n., T.doipuiensis sp. n., T.doisuthepensis sp. n., T.dongnaiensis sp. n., T.falciforceps sp. n., T.falciformis sp. n., T.feresiantarensis sp. n., T.filiforceps sp. n., T.fulleri sp. n., T.phukradungensis sp. n., T.geiserae sp. n., T.giulianae sp. n., T.infida sp. n., T.jakli sp. n., T.khaosoidaoensis sp. n., T.kiriromensis sp. n., T.koi sp. n., T.kollae sp. n., T.konchurangensis sp. n., T.kontumensis sp. n., T.loeiensis sp. n., T.lucai sp. n., T.microfurcata sp. n., T.microspinosa sp. n., T.multiangulata sp. n., T.nahaeoensis sp. n., T.nakaiensis sp. n., T.namnaoensis sp. n., T.neouncinata sp. n., T.nonglomensis sp. n., T.nussi sp. n., T.olegi sp. n., T.pahinngamensis sp. n., T.pailinensis sp. n., T.parasetuliforceps sp. n., T.paratonkinensis sp. n., T.petrpacholatkoi sp. n., T.phatoensis sp. n., T.phoupaneensis sp. n., T.pluriuncinata sp. n., T.pseudoliangheensis sp. n., T.pseudoruiliensis sp. n., T.pseudouncinata sp. n., T.quadriforceps sp. n., T.quadrifurcata sp. n., T.rihai sp. n., T.romae sp. n., T.rubrithorax sp. n., T.sapana sp. n., T.semidamadiensis sp. n., T.semipingjiangensis sp. n., T.semiruiliensis sp. n., T.semishanensis sp. n., T.setuliforceps sp. n., T.shanensis sp. n., T.smetsi sp. n., T.margheritae sp. n., T.soppongana sp. n., T.spanglerorum sp. n., T.spinotibialis sp. n., T.subrotundata sp. n., T.tanahrataensis sp. n., T.thainguyensis sp. n., T.trilobiforceps sp. n., T.ululalatensis sp. n., T.umphangensis sp. n., T.vari sp. n., T.veliformis sp. n., T.vientianeensis sp. n., and T.xiengkhouangensis sp. n. A key to the Indochinese Tetraserica species is given and distributions as well as the habitus and male genitalia of all species are illustrated.

Landscape genetics indicate recently increased habitat fragmentation in African forest-associated chafers

Today, indigenous forests cover less than 0.6% of South Africa's land surface and are highly fragmented. Most forest relicts are very small and typically occur in fire-protected gorges along the eastern Great Escarpment. Yet, they hold a unique and valuable fauna with high endemism and ancient phylogenetic lineages, fostered by long-term climatic stability and complex microclimates. Despite numerous studies on southern African vegetation cover, the current state of knowledge about the natural extension of indigenous forests is rather fragmentary. We use an integrated approach of population-level phylogeography and climatic niche modeling of forest-associated chafer species to assess connectivity and extent of forest habitats since the last glacial maximum. Current and past species distribution models ascertained potential fluctuations of forest distribution and supported a much wider potential current extension of forests based on climatic data. Considerable genetic admixture of mitochondrial and nuclear DNA among many populations and an increase in mean population mutation rate in Extended Bayesian Skyline Plots of all species indicated more extended or better connected forests in the recent past (<5 kya). Genetic isolation of certain populations, as revealed by population differentiation statistics (GST'), as well as landscape connectivity statistics and habitat succession scenarios suggests considerable loss of habitat connectivity. As major anthropogenic influence is likely, conservational actions need to be considered.

Bayesian species delimitation in Pleophylla chafers (Coleoptera) - the importance of prior choice and morphology

BACKGROUND

Defining species units can be challenging, especially during the earliest stages of speciation, when phylogenetic inference and delimitation methods may be compromised by incomplete lineage sorting (ILS) or secondary gene flow. Integrative approaches to taxonomy, which combine molecular and morphological evidence, have the potential to be valuable in such cases. In this study we investigated the South African scarab beetle genus Pleophylla using data collected from 110 individuals of eight putative morphospecies. The dataset included four molecular markers (cox1, 16S, rrnL, ITS1) and morphometric data based on male genital morphology. We applied a suite of molecular and morphological approaches to species delimitation, and implemented a novel Bayesian approach in the software iBPP, which enables continuous morphological trait and molecular data to be combined.

RESULTS

Traditional morphology-based species assignments were supported quantitatively by morphometric analyses of the male genitalia (eigenshape analysis, CVA, LDA). While the ITS1-based delineation was also broadly congruent with the morphospecies, the cox1 data resulted in over-splitting (GMYC modelling, haplotype networks, PTP, ABGD). In the most extreme case morphospecies shared identical haplotypes, which may be attributable to ILS based on statistical tests performed using the software JML. We found the strongest support for putative morphospecies based on phylogenetic evidence using the combined approach implemented in iBPP. However, support for putative species was sensitive to the use of alternative guide trees and alternative combinations of priors on the population size (θ) and rootage (τ 0 ) parameters, especially when the analysis was based on molecular or morphological data alone.

CONCLUSIONS

We demonstrate that continuous morphological trait data can be extremely valuable in assessing competing hypotheses to species delimitation. In particular, we show that the inclusion of morphological data in an integrative Bayesian framework can improve the resolution of inferred species units. However, we also demonstrate that this approach is extremely sensitive to guide tree and prior parameter choice. These parameters should be chosen with caution - if possible - based on independent empirical evidence, or careful sensitivity analyses should be performed to assess the robustness of results. Young species provide exemplars for investigating the mechanisms of speciation and for assessing the performance of tools used to delimit species on the basis of molecular and/or morphological evidence.