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The taxonomic concepts of Blapimorpha and Opatrinae (informal and traditional, morphology‐based groupings among darkling beetles) are tested using molecular phylogenetics and a reassessment of larval and adult morphology to address a major phylogeny‐classification gap in Tenebrionidae. Instead of a holistic approach (family‐level phylogeny), this study uses a bottom‐up strategy (tribal grouping) in order to define larger, monophyletic lineages within Tenebrioninae. Sampling included representatives of 27 tenebrionid tribes: Alleculini, Amarygmini, Amphidorini, Blaptini, Bolitophagini, Branchini, Cerenopini, Coniontini, Caenocrypticini, Dendarini, Eulabini, Helopini, Lagriini, Melanimini, Opatrini, Pedinini, Phaleriini, Physogasterini, Platynotini, Platyscelidini, Praociini, Scaurini, Scotobiini, Tenebrionini, Trachyscelini, Triboliini and Ulomini. Molecular analyses were based on DNA sequence data from four non‐overlapping gene regions: carbamoyl‐phosphate synthetase domain of rudimentary (CAD) (723 bp), wingless (wg) (438 bp) and nuclear ribosomal 28S (1101 bp) and mitochondrial ribosomal 12S (363 bp). Additionally, 15 larval and imaginal characters were scored and subjected to an ancestral state reconstruction analysis. Results revealed that Amphidorini, Blaptini, Dendarini, Pedinini, Platynotini, Platyscelidini and Opatrini form a clade which can be defined by the following morphological features: adults—antennae lacking compound/stellate sensoria; procoxal cavities externally and internally closed, intersternal membrane of abdominal ventrites 3–5 visible; paired abdominal defensive glands present, elongate, not annulated; larvae—prolegs enlarged (adapted for digging); ninth tergite lacking urogomphi. To accommodate this monophyletic grouping (281 genera and ∼4000 species), the subfamily Blaptinae sens. nov. is resurrected. Prior to these results, all of the tribes within Blaptinae were classified within the polyphyletic subfamily Tenebrioninae. The non‐monophyletic nature of Terebrioninae has already been postulated by previous authors, yet no taxonomic decisions were made to fix its status. The reinstatement of Blaptinae, which groups ∼50% of the former Tenebrioninae, helps to clarify phylogenetic relations among the whole family and is the first step towards a complete higher‐level revision of Tenebrionidae. The Central Asian tribe Dissonomini (two genera, ∼30 species) was not included in Blaptinae due to a lack of representatives in the performed phylogenetic analyses; however, based on morphological features, the tribe is listed as a potential addition to the subfamily.

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The tracheal (respiratory) system is regarded as one of the key elements which enabled insects to conquer terrestrial habitats and, as a result, achieve extreme species diversity. Despite this fact, anatomical data concerning this biological system is relatively scarce, especially in an ontogenetic context. The purpose of this study is to provide novel and reliable information on the post-embryonic development of the tracheal system of holometabolous insects using micro-computed tomography methods. Data concerning the structure of the respiratory system acquired from different developmental stages (larvae, pupae and adults) of a single insect species (Tenebrio molitor) are co-analysed in detail. Anatomy of the tracheal system is presented. Sample sizes used (29 individuals) enabled statistical analysis of the results obtained. The following aspects have been investigated (among others): the spiracle arrangement, the number of tracheal ramifications originating from particular spiracles, the diameter of longitudinal trunks, tracheal system volumes, tracheae diameter distribution and fractal dimension analysis. Based on the data acquired, the modularity of the tracheal system is postulated. Using anatomical and functional factors, the following respiratory module types have been distinguished: cephalo-prothoracic, metathoracic and abdominal. These modules can be unambiguously identified in all of the studied developmental stages. A cephalo-prothoracic module aerates organs located in the head capsule, prothorax and additionally prolegs. It is characterised by relatively thick longitudinal trunks and originates in the first thoracic spiracle pair. Thoracic modules support the flight muscles, wings, elytra, meso- and metalegs. The unique feature of this module is the presence of additional longitudinal connections between the neighbouring spiracles. These modules are concentrated around the second prothoracic and the first abdominal spiracle pairs. An abdominal module is characterised by relatively thin ventral longitudinal trunks. Its main role is to support systems located in the abdomen; however, its long visceral tracheae aerate organs situated medially from the flight muscles. Analysis of changes of the tracheal system volume enabled the calculation of growth scaling among body tissues and the volume of the tracheal system. The data presented show that the development of the body volume and tracheal system is not linear in holometabola due to the occurrence of the pupal stage causing a decrease in body volume in the imago and at the same time influencing high growth rates of the tracheal system during metamorphosis, exceeding that ones observed for hemimetabola.

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This paper summarizes currently available morphological data on larval stages of representatives of the 'Opatrinoid' clade (Tenebrionidae: Tenebrioninae). Literature research revealed that larval morphology of approximately 6% of described species representing this lineage is currently known (139 out of ~ 2325 spp.). Larvae of the five following species are described and illustrated: Zadenos mulsanti (Dendarini: Melambiina; South Africa), Blapstinus histricus, Blapstinus longulus, Trichoton sordidum (Opatrini: Blapstinina; North America), and Eurynotus rudebecki (Platynotini: Eurynotina; South Africa). The majority of studied larvae were associated with adults using molecular tools, resulting in an updated phylogeny of the 'Opatrinoid' clade. This revised phylogeny provides an evolutionary context for discussion of larval morphology. Based on the morphological and molecular evidence, the following synonym is proposed within Blapstinina: Trichoton Hope, 1841 (= Bycrea Pascoe, 1868 syn. nov.). Based on this decision, a new combination is introduced: Trichoton villosum Pascoe, 1868 comb. nov. The economic importance of the 'Opatrinoid' clade larvae is also briefly discussed, as well as potential future avenues of research.

The monophyly of the North and South American endemic subtribe Blapstinina (Tenebrionidae: Opatrini) is tested through phylogenetic analyses using five molecular markers [nuclear ribosomal 28S (28S), cytochrome oxidase subunit II (COII), arginine kinase (ArgK), carbamoyl‐phosphate synthetase domain of rudimentary (CAD), wingless (wg)]. Representatives of several opatrinoid subtribes were taken into consideration, including other geographically overlapping endemic genera, namely Ammodonus, Ephalus and Pseudephalus (all previously considered representatives of Ammobiina). A comparative study of morphology was performed to assess resulting phylogenetic hypotheses. Analyses support the monophyly of Blapstinina; however, they also strongly indicate that Ammodonus should be included within the subtribe. Mecysmus is nested within Blapstinus and therefore, a new synonymy, Blapstinus (= Mecysmus syn.n.), and the following combinations are introduced: Blapstinus advena comb.n., B. angustus comb.r., B. laticollis comb.n., B. parvulus comb.n., B. tenuis comb.n. Morphological analysis showed a close affiliation between Ephalus and Pseudephalus. Based on these results, Pseudephalus is synonymized with Ephalus [Ephalus (= Pseudephalus syn.n.)], and the following combination is introduced: Ephalus brevicornis comb.n. Recovered topologies also strongly support transferring Ephalus stat.n. into Opatrina, making the distribution of Opatrina amphi‐Atlantic.

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