Verschmelzung von Antennomeren (Symphysocerie) als Regelfall bei Temnorhynchus repandus Burmeister, 1847, sowie phylogenetische, taxonomische, faunistische und nomenklaturische Anmerkungen zu diversen Taxa dieser Gattung (Coleoptera. Scarabaeoidea, Melolo

Abstract

Symphysocery, i.e. fusion of antennomeres from the phylogenetical point of view or anarthrogenesis from the morphogenetical point of view respectively, is often recorded in the “pleurostict” Scarabaeoidea. It is the normal case (92% of all individuals) in Temnorhynchus repandus Burm. Based on the morphological structures of symphysocery, the following hypotheses on the morphogenesis of the Temnorhynchus or the Pentodontini antenna respectively are elaborated: 1. The partial or entire anarthrogenesis of the flagellomeres is heritable. 2. The anarthrogenesis is transmitted autosomally. 3. The arthrogenesis goes by the “spreading fields” mechanism. 4. The building of an intersegmental area begins caudally and proceeds, both dorsally and ventrally, in cranial direction. 5. A complete or partial symphysocery is caused by genetical stopping the arthrogenesis before its termination. 6. A hypothetical model for the arthrogenesis is proposed. The last but one subdivision takes place between the antennomeres IV and (V + VI), the last one between V and VI. Sokoloff's hypothesis on antennal morphogenesis is criticised. — Mutation research in Tenebrio and Tribolium indicates that antenna oligomerism is a frequent phenomenon, but longitudinal polymerism is very rare. Hence, apomorphical reduction of the number of antennomeres bears a higher probability of convergence than apomorphical increase. — In the taxonomical part the following changes and novelties are stated. The genus‐group name Temnorhynchus Hope, 1837, is proposed as valid. The female of Temnorhynchus overlaeti Burgeon is described, the male is redescribed. A paralectotype of T. glauningi Kolbe (syn. of T. coronatus) is declared as hololectotype because of a mistake of the designator. New diagnose and a distribution map for T. rugatus Kolbe and T. flavipennis Arrow are given. T. diana chinchoxonicus Kolbe, 1887, is synonymized with T. tridentatus Lansberge, 1886. Lectotypes for the former are designated. T. diana guineensis Kolbe, 1887. is synonymized with T. luna Fairmaire, 1868. A new diagnosis and chorology for the latter are given. T. luna ab. punctiluna Endrödi, 1976, is synonymized with T. coronatus (F., 1781). T. galeatus Künckel, 1887, is synonymized with T. coronatus antiochus Fairmaire, 1868. T. congoanus Paulian, 1946, is restituated as the species‐name for the Gabonian specimens of T. raffrayi sensu Endrödi. A new diagnosis of T. raffrayi Fairmaire is given. T. zambezianus nov. sp. from Mozambique and Malawi and T. zambezianus occidentalis nov. ssp. from Zambia and Botswana are described. T. zambezianus differs constantly from the T. raffrayi‐group by the club‐like apex of the paramera.

Systematics of the enigmatic South American Streblopus Van Lansberge, 1874 dung beetles and their transatlantic origin: a case study on the role of dispersal events in the biogeographical history of the Scarabaeinae (Coleoptera: Scarabaeidae)

“…In other words, which are the articles involved in the reduction of total number of antennomeres? Krell (1992) presented a rather complete discussion on the morphogenesis of the antennal articles in scarab beetles, and we base much of our discussion on his conclusions. During the development of the insect antenna, flagellomeres are added by subdivision of a single unarticulate structure (Matsuda 1965;Krell 1992;Minelli 2004Minelli , 2017 by a process called arthrogenesis (Krell 1992).…”

“…Krell (1992) presented a rather complete discussion on the morphogenesis of the antennal articles in scarab beetles, and we base much of our discussion on his conclusions. During the development of the insect antenna, flagellomeres are added by subdivision of a single unarticulate structure (Matsuda 1965;Krell 1992;Minelli 2004Minelli , 2017 by a process called arthrogenesis (Krell 1992). As successive arthrogeneses divide a previously unarticulated portion of the developing antenna into two halves, if the expression of any particular arthrogenesis is suppressed, then the ancestral separation of two flagellomeres is lost and the area corresponding to those two flagellomeres in the ancestral form will be seen as a single flagellomere in the apomorphic condition of the antenna.…”

“…As successive arthrogeneses divide a previously unarticulated portion of the developing antenna into two halves, if the expression of any particular arthrogenesis is suppressed, then the ancestral separation of two flagellomeres is lost and the area corresponding to those two flagellomeres in the ancestral form will be seen as a single flagellomere in the apomorphic condition of the antenna. While this process is denominated anarthrogenesis from a developmental point of view, from a phylogenetic perspective it is called symphysocery (Krell 1992). Indeed, symphysocery is widely present among beetles (Minelli 2004(Minelli , 2017, and several groups of dung beetles show it.…”

“…In the Neotropical fauna, two genera are defined, among other minor characters, based on the presence of 8-articulate antennae rather than the ancestral 9-articulate antennae of dung beetles, both in Dichotomiini: Chalcocopris Burmeister, 1846 and Isocopris Pereira & Martínez, 1960(Rossini & Vaz-de-Mello 2015, 2017. Nevertheless, as detailed by Krell (1992), since anarthrogenesis in the antennal funicle seems to have little effect on the overall fitness of the individual bearing the mutation(s) responsible for it (contrary to anarthrogenesis in the apical lamellae, scape and pedicel, which interferes more directly with the functional roles of the antennae and, therefore, affects fitness), the number of articles in the antennal funicle seems to be fairly plastic among beetles, and convergences and parallelisms (due to either developmental constraints or selection of genes with pleiotropic effects on anarthrogenesis, or even genetic drift) are not expected to occur so rarely.…”

Revision of the subgenus Orphnus (Phornus) (Coleoptera, Scarabaeidae, Orphninae)

“…In species of several Sericinae genera, the number of antennomeres can be either nine or ten and this character is considered highly homoplastic and unsuitable for phylogenetic studies (Ahrens 2006). Krell (1992) reported symphysocery in over 90 percent of examined specimens of the African rhinoceros beetle Temnorhynchus repandus Burmeister (Dynastinae). However, in the Orphninae symphysocery was previously unknown.…”