[Most Recent Entries] [Calendar View]
Sunday, August 28th, 2022
| Time | Event | ||||||||
| 7:46a | [PaleoEntomology • 2022] Evolution of Filter-Feeding in Aquatic Insects dates back to the Middle Triassic: New Evidence from Stem-group Mayflies (Insecta, Ephemerida) from Grès à Voltzia, Vosges, France
Abstract In the aquatic insects, mayfly nymphs have developed a remarkable diversity of life strategies and feeding habits. However, the early evolution of these strategies and the role of mayfly nymphs in freshwater palaeoecosystems remain largely unknown. We investigated fossil mayfly nymphs from the Grès à Voltzia Formation from the Middle Triassic, France, which represents the oldest known outcrop yielding a diverse mayfly fauna. We focused on three species, namely Mesoplectopteron longipes, Vogesonympha ludovici and Triassoephemera punctata, and investigated both original type material and numerous previously unstudied specimens. As a result, we provide a new interpretation of their morphology, life histories, and systematics: the nymphs of M. longipes, V. ludovici and T. punctata were aquatic and at least the former two species undoubtedly lived in flowing water as passive filter-feeders. This finding represents the so far earliest occurrence of this feeding strategy in aquatic insects. The most obvious morphological adaptations to this lifestyle are long filtering setae arranged in rows on forelegs, analogous to some modern mayfly nymphs. We place the three investigated species M. longipes, V. ludovici and T. punctata in a newly established, unranked higher taxon, Sinebranchia, representing the sister group to Heptabranchia (Coxoplectoptera + Ephemeroptera). Sinebranchia share a single-segmented tarsus synapomorphic with Heptabranchia, but retain the plesiomorphic condition of double tarsal claws. Sinebranchia are also characterized by their autapomorphic lack of tracheal gills, probably connected to their life in flowing, well-oxygenated water. Keywords: Ephemeroptera, filter-feeding, fossil, life history, mayfly, nymph, Mesozoic 
Pavel Sroka and Arnold H. Staniczek. 2022. Evolution of Filter-Feeding in Aquatic Insects dates back to the Middle Triassic: New Evidence from Stem-group Mayflies (Insecta, Ephemerida) from Grès à Voltzia, Vosges, France. Papers in Palaeontology. DOI: 10.1002/spp2.1456 | ||||||||
| 7:50a | [Herpetology • 2022] Hynobius oni • A New Species of Lotic Breeding Salamander (Caudata: Hynobiidae) from Shikoku, Japan
Abstract Background: Hynobius hirosei is a lotic-breeding salamander endemic to Shikoku Island in western Japan. Significant allozymic and morphological differences have been found among the populations of this species; however, the degree and pattern of intraspecific variation have not been surveyed using a sufficient number of samples. Methods: For the taxonomic revision of H. hirosei, we conducted genetic and morphological surveys using samples collected throughout the distribution. Phylogenetic analysis using the cytochrome b region of mitochondrial DNA and population structure analysis using single nucleotide polymorphisms were conducted to evaluate the population structure within the species and the degree of genetic differentiation. Subsequently, a morphological survey based on multivariate and univariate analyses was performed to assess the morphological variation. Results: Genetic analyses revealed three genetic groups (Tsurugi, Central, and Nanyo) within H. hirosei, with the Nanyo group distributed allopatrically from the others, and the Tsurugi and Central groups distributed parapatrically with the formation of a hybrid zone between them. The Nanyo group was morphologically distinguishable from the remaining samples, including the topotype of H. hirosei, based on a smaller body size and several ratio values of characters to snout-vent length, longer axilla-groin distance, shorter tail length, shorter internarial distance, longer upper eyelid length, and larger medial tail width. These results support the notion that the Nanyo group is an undescribed species. However, the remaining genetically differentiated groups could not be divided in the present study. Herein, we described the Nanyo group as a new species.
Hynobius oni sp. nov. (Japanese name: Nan-yo-sanshouo) Diagnosis: A large-sized species (adult SVL 73.6–87.5 mm in males) of the lotic-breeding Hynobius, breeding in montane streams; dorsum uniformly dark reddish brown and immaculate in adult; tips of fore- and hindlimbs adpressed on body scarcely meeting (overlap of −2.0 to 0.0 costal folds in males); fifth toe well developed; ova large, pigmentless; egg sacs relatively long and crescent in shape, with distinct whiptail structure on free end; larvae lack claws on their tips of fingers and toes; most similar to H. hirosei, but distinct based on its smaller body size, longer axilla-groin distance, shorter tail length, shorter internarial distance, longer upper eyelid length, and larger medial tail width. Hynobius oni is genetically closer to H. sematonotos than H. hirosei based on mtDNA; however, H. oni has no large markings on the body, in contrast to many silvery spots on H. sematonotos, and a larger SVL than H. sematonotos.
Etymology: The specific name is derived from the “Oni” in Japanese, which is a traditional Japanese demon. The habitats of the new species are areas where prior generations believed that the Oni and Ushi-oni, which is a type of Oni, occurred. The type locality is located in the Oni-ga-jo Mountains, which is considered to be the castle of the Oni. Conclusions: In the present study, the actual genetic population structure and degree of genetic divergence within Hynobius hirosei, which has been reported to have large genetic intraspecies divergence, were evaluated using mtDNA and nuDNA markers (SNP). Phylogenetic analysis using mtDNA revealed three divergent lineages, including the Tsurugi, Central, and Nanyo groups (genetic distance: 6.9–10.3% in cyt b). Further, STRUCTURE analysis using SNP revealed that the Nanyo group is genetically isolated from the other groups and the Tsurugi and Central groups form hybrid zones. Morphological analyses also revealed that the Nanyo is distinct from the other groups. Collectively, these results strongly indicate that Nanyo group is a distinct species, and is referred to as H. oni sp. nov. in this study. Sally Kanamori, Kanto Nishikawa, Masafumi Matsui and Shingo Tanabe. 2022. A New Species of Lotic Breeding Salamander (Amphibia, Caudata, Hynobiidae) from Shikoku, Japan. PeerJ. 10:e13891. DOI: 10.7717/peerj.13891 | ||||||||
| 9:41a | [Botany • 2022] Euphorbia marciae (Euphorbiaceae) • A New Species from the Balsas Depression of Mexico
Abstract Euphorbia marciae, a new species from the lowlands of the Balsas Depression in southwestern Mexico, is described and illustrated. The species was first collected by the renowned botanist George B. Hinton during his explorations of the area in the 1930s. It is known from only five collections made in northwestern Guerrero and the extreme southwestern portion of the state of México, at elevations from 250 to 610 m. Vegetation of the area is tropical deciduous forest. Euphorbia marciae belongs to Euphorbia subg. Chamaesyce sect. Anisophyllum and resembles E. apatzingana, E. hyssopifolia, and E. nutans. However, it differs from these species in having smooth seeds. The seeds are nearly identical to those of E. pionosperma, an endemic species occurring in the Sierra Madre Occidental of eastern Sonora and western Chihuahua. However, the leaves of E. pionosperma are more conspicuously serrate and have larger stipules. In addition, Euphorbia pionosperma has smaller involucres and involucral appendages. Following IUCN Redlist criteria, E. marciae should be treated as Data Deficient (DD) until the species can be relocated and its populations field evaluated. Keywords: IUCN Redlist; sect. Anisophyllum; subg. Chamaesyce; tropical deciduous forest
Euphorbia marciae V.W. Steinm., Etymology Euphorbia marciae is named after my mother, Marcia Marie Steinmann, née Bradley (1938–2018), who not only gave me my life, but always offered unconditional support and encouragement, especially with regard to my interest in biology. Victor W. Steinmann. 2022. Euphorbia marciae: A New Species from the Balsas Depression of Mexico. Taxonomy. 2(3); 291-297. DOI: 10.3390/taxonomy2030023 |
| << Previous Day |
2022/08/28 [Calendar] |
Next Day >> |