Sister-group Relationship Research Articles

Morphology and phylogenetic significance of the thoracic muscles in Psocodea (Insecta: Paraneoptera).

The thoracic musculature of the insect order Psocodea has been examined in only a few species of a single suborder to date. In the present study, we examined the thoracic musculature of species selected from all three suborders of Psocodea to elucidate the ground plan of the order and to examine the phylogenetic utility of the character system. The sister-group relationship between the suborders Troctomorpha and Psocomorpha received support from two novel nonhomoplasious synapomorphies, although the support from other morphological characters for this relationship is ambiguous. The sister-group relationship between the infraorders Epipsocetae and Psocetae also received support from one nonhomoplasious synapomorphy, although no other morphological characters supporting this relationship have been identified to date. The present examination revealed the potential of thoracic muscle characters for estimating deep phylogeny, possibly including interordinal relationships.

Family–level phylogeny of infraorder Systellognatha (Insecta: Plecoptera) inferred from mitochondrial genomes

AbstractSystellognatha is a monophyletic group within stoneflies containing seven families in two superfamilies. However, the family–level phylogeny within Systellognatha is largely unresolved, with some controversial hypotheses generated by molecular data. In this study, we sequenced one complete and three nearly complete mitochondrial genomes (mitogenomes) representing three systellognathan families (including one newly described family), to recover the phylogeny of all seven extant systellognathan families. We tested the effect of heterogeneous sequence divergence within mitogenome sequences on phylogenetic reconstruction. To study incongruent topologies supported by different datasets, we also utilized four–cluster likelihood mapping to elucidate these phylogenetic questions. We found a low degree of compositional heterogeneity in systellognathan mitogenomes. Our results showed that phylogenetic analyses with various datasets under site–homogeneous models failed to recover the Perloidea and Pteronarcyoidea as monophyletic groups. However, Bayesian inference with a site–heterogeneous model (CAT + GTR) recovered Perloidea as monophyletic. Our results confirm a sister–group relationship between Chloroperlidae and Perlodidae. Despite all phylogenetic analyses failed to recover the Pteronarcyoidea as monophyletic, the analyses with site–heterogeneous model based on PCG12, PCG12R and PCGR datasets reconstructed the same relationships among Pteronarcyidae, Peltoperlidae, Styloperlidae and Perloidea. Our study shows the power of the site–heterogeneous models in resolving phylogeny within Systellognatha and provides a new insight into the phylogeny of this group.

Addition to the known diversity of Chinese freshwater planarians: integrative description of a new species of Dugesia Girard, 1850 (Platyhelminthes, Tricladida, Dugesiidae)

The present paper describes a new species of freshwater flatworm of the genus Dugesia from Guizhou province, China, based on an integrative approach, combining morphological, histological and molecular information. This new species, Dugesia gemmulata Sun & Wang, sp. nov., is characterized by the ventral part of the most posterior section of the bursal canal being provided with a voluminous, ellipsoidal muscular swelling; sac- or egg-shaped seminal vesicle situated near the ventral body surface in anterior portion of the penis bulb; postero-dorsal wall of seminal vesicle communicating with a narrow duct that first runs almost vertically but then shows a postero-dorsally directed loop before connecting with a small diaphragm; an ejaculatory duct opening terminally or subterminally; an asymmetrical penis papilla, with its dorsal lip being provided with a bump; oviducts opening asymmetrically into female copulatory apparatus, with the left oviduct opening into the common atrium and the right oviduct opening into the vaginal section of the bursal canal. Molecular phylogenetic analyses revealed that the new species belongs to a clade comprising species from the Australasian and Oriental regions, while it shares a sister-group relationship with D. umbonata Song & Wang, 2020, a species characterized by a muscular swelling on the dorsal side of its bursal canal.

Identification, characterization, and molecular phylogeny of scorpion enolase (Androctonus crassicauda and Hemiscorpius lepturus)

Scorpions are the oldest terrestrial fauna with an ancient evolutionary history. To study the origins of scorpions, we conducted a molecular phylogenetic study of the arthropod using slowly evolving enolase sequences. In this study, we used deep RNA-seq technology to identify the enolase sequences of Androctonus crassicauda and Hemiscorpius lepturus scorpions. The scorpion’s enolase sequences were in silico analyzed to predict the protein structures, physicochemical characterization, and exon-intron organization. The enolase of the scorpion was found to be a protein of 433 amino acids with a molecular mass of ∼47 kDa and an acidic isoelectric point. Here, we reported the existence of 8 exons and an inner GC/AG intron for scorpion enolase. Using homology modeling, the enolase of the scorpions was found to be very conservative during the evolution process. Furthermore, our phylogenetic analysis indicated the independent evolution of the Buthidae family from other scorpions and also the sister group relationship of Hemiscorpionidae with the Caraboctonidae families. The scorpions’ enolase sequences demonstrated a close fit to those of spiders, followed by mite counterparts. This strongly supports our phylogeny analysis, which indicates a sister-group relationship between scorpions and spiders and their common ancestors with mites. This study provided support for the pairing of scorpions with spiders, mites, etc. using enolase as a nuclear gene. Our molecular clock analyzes of the arthropod show that the most recent common ancestor of arachnids and insects were diversified in the Cryogenian period of Neoproterozoic era, earlier than dates reported from fossil records.

The chloroplast genomes of Sanicula (Apiaceae): plastome structure, comparative analyses and phylogenetic relationships

Sanicula (Apiaceae subfam. Saniculoideae) is a taxonomically difficult genus of medicinal value. Its distribution center is in China, where there are 18 species (11 of which are endemic). To provide plastid genome resources, whole chloroplast genomes of five Sanicula species (S. flavovirens, S. giraldii, S. lamelligera, S. odorata and S. rubriflora) were sequenced and compared to the previously published S. orthacantha plastome. These genomes exhibit a typical quadripartite structure. All contain 129 different genes, including 84 protein‐coding, 37 tRNA and 8 rRNA genes. The loci rpl2, matK, psbA and ycf1 are the most variable. Results of maximum likelihood analysis of 90 whole plastome sequences from Apioideae and Saniculoideae and the outgroup Hydrocotyle (Araliaceae) suggest sectional relationships in Sanicula different from the traditional classification system, but support the monophyly of Apioideae and its sister group relationship to Saniculoideae and show concordant topologies to nrDNA ITS and other plastome‐based phylogenies. Sanicula orthacantha and S. chinensis form a sister group to S. lamelligera and S. odorata, consecutively. These four species comprise a sister group to the clade of S. rubriflora and S. flavovirens, with this entire group sister to S. giraldii. The plastid genome resources provided herein will be important for future systematic, evolutionary, phylogenomic and population‐level studies of Sanicula.

Mitogenomic phylogeny of Typhlocybinae (Hemiptera: Cicadellidae) reveals homoplasy in tribal diagnostic morphological traits.

The subfamily Typhlocybinae is a ubiquitous, highly diverse group of mostly tiny, delicate leafhoppers. The tribal classification has long been controversial and phylogenetic methods have only recently begun to test the phylogenetic status and relationships of tribes. To shed light on the evolution of Typhlocybinae, we performed phylogenetic analyses based on 28 newly sequenced and 19 previously sequenced mitochondrial genomes representing all currently recognized tribes. The results support the monophyly of the subfamily and its sister‐group relationship to Mileewinae. The tribe Zyginellini is polyphyletic with some included genera derived independently within Typhlocybini. Ancestral character state reconstruction suggests that some morphological characters traditionally considered important for diagnosing tribes (presence/absence of ocelli, development of hind wing submarginal vein) are homoplastic. Divergence time estimates indicate that the subfamily arose during the Middle Cretaceous and that the extant tribes arose during the Late Cretaceous. Phylogenetic results support establishment of a new genus, Subtilissimia Yan & Yang gen. nov., with two new species, Subtilissimia fulva Yan & Yang sp. nov. and Subtilissimia pellicula Yan & Yang sp. nov.; but indicate that two previously recognized species of Farynala distinguished only by the direction of curvature of the processes of the aedeagus are synonyms, that is, Farynala dextra Yan & Yang, 2017 equals Farynala sinistra Yan & Yang, 2017 syn. nov. A key to tribes of Typhlocybinae is provided.

Repetitive Elements, Sequence Turnover and Cyto-Nuclear Gene Transfer in Gymnosperm Mitogenomes.

Among the three genomes in plant cells, the mitochondrial genome (mitogenome) is the least studied due to complex recombination and intergenomic transfer. In gymnosperms only ∼20 mitogenomes have been released thus far, which hinders a systematic investigation into the tempo and mode of mitochondrial DNA evolution in seed plants. Here, we report the complete mitogenome sequence of Platycladus orientalis (Cupressaceae). This mitogenome is assembled as two circular-mapping chromosomes with a size of ∼2.6 Mb and which contains 32 protein-coding genes, three rRNA and seven tRNA genes, and 1,068 RNA editing sites. Repetitive sequences, including dispersed repeats, transposable elements (TEs), and tandem repeats, made up 23% of the genome. Comparative analyses with 17 other mitogenomes representing the five gymnosperm lineages revealed a 30-fold difference in genome size, 80-fold in repetitive content, and 230-fold in substitution rate. We found dispersed repeats are highly associated with mitogenome expansion (r = 0.99), and most of them were accumulated during recent duplication events. Syntenic blocks and shared sequences between mitogenomes decay rapidly with divergence time (r = 0.53), with the exceptions of Ginkgo and Cycads which retained conserved genome structure over long evolutionary time. Our phylogenetic analysis supports a sister group relationship of Cupressophytes and Gnetophytes; both groups are unique in that they lost 8–12 protein-coding genes, of which 4–7 intact genes are likely transferred to nucleus. These two clades also show accelerated and highly variable substitution rates relative to other gymnosperms. Our study highlights the dynamic and enigmatic evolution of gymnosperm mitogenomes.

Phylogenetic relationships of a new catfish of the genus Trichomycterus (Siluriformes, Trichomycteridae) from the Brazilian Cerrado, and the role of Cenozoic events in the diversification of mountain catfishes

The Brazilian Cerrado highlands shelter the headwaters of the three largest South American hydrographic basins, where a great species diversity is concentrated, but some biological groups are still insufficiently known. The focal taxa of this study are trichomycterid catfishes of the subgenus Cryptocambeva, genusTrichomycterus, endemic to mountain areas of south-eastern Brazil. The primary objective of this study is to test through a molecular phylogeny if a new species collected in streams of the upper Rio Paraná basin draining the Serra da Canastra is sister toT. macrotrichopterus, endemic to the upper Rio São Francisco at another facet of the Serra da Canastra, as suggested by morphological data. The analysis corroborated sister group relationships between these two species, besides supporting four main clades inCryptocambeva, each of them endemic to distinct mountain regions. A time-calibrated analysis supported the divergence timing between the new species andT. macrotrichopterusat the Pliocene, which is chronologically compatible with the final period of intense fluvial configuration re-arrangement, when São Francisco headwater streams were captured by the Paraná basin. The new species herein described is similar toT. macrotrichopterusand distinguished from all other species ofCryptocambevaby having a long pectoral-fin filament. These two species are distinguished from each other by characteristics of the latero-sensory system, colour pattern and bone morphology.

Is Gymnophallus Odhner, 1900 (Trematoda: Gymnophallidae) polyphyletic? A new hypothesis based on phylogenetic position of Gymnophallus deliciosus (Olsson, 1893).

Gymnophallus deliciosus is a type species of the genus Gymnophallus. We collected this trematode species from gallbladder of Larus argentatus caught in the White Sea (Kandalaksha Bay, Chupa Inlet) and obtained the sequences of its nuclear 18S and 28S rDNA genes. Our recently obtained phylogenetic data support a sister group relationship of this species with G. choledochus. However, other species of the genus Gymnophallus-G. australis (KM246854) and G. minutus (KM268111)-do not branch with the group G. choledochus + G. deliciosus or with each other. Our study revealed that the genus Gynmnophallus is probably a polyphyletic taxon, and the genus affiliation of its representatives should be re-examined in future.

Partial redescriptions of three holothurians with hook papillae (Apodida: Chiridotidae): Taeniogyrus japonicus (Marenzeller, 1882), T. dendyi (Mortensen, 1925), Scoliorhapis theelii (Heding, 1928).

New specimens of Taeniogyrus japonicus (Marenzeller) were collected from Iwami coast and Sado island of the Sea of Japan. According to detailed observations of external and internal organs, we transferred T. japonicus, T. dendyi (Mortensen), and Scoliorhapis theelii (Heding) to the newly revived genus Scoliodota, with a large retractor organ and hook papillae as major diagnostic characters. We also concluded that Scoliorhapis dianthus Solis-marin et al. is a synonym of T. japonicus. Our molecular phylogeny and genetic distance analysis showed that specimens from Iwami and specimens from Sado of T. japonicus form a monophyletic clade, indicating that they are most likely the same species despite their morphological variation. The phylogenetic analysis also indicated that T. japonicus forms a sister group relationship with Taeniogyrus verruculosus Yamana Tanaka and Scoliorhapis sesokoensis Yamana Tanaka, suggesting that Taeniogyrus is not monophyletic. Taken together, these results brought new insights to sea cucumber diversity in Japanese waters.

ROV observations reveal infection dynamics of gill parasites in midwater cephalopods

Gill parasites of coleoid cephalopods are frequently observed during remotely operated vehicle (ROV) dives in the Monterey Submarine Canyon. However, little knowledge exists on the identity of the parasite species or their effects on the cephalopod community. With the help of ROV-collected specimens and in situ footage from the past 27 years, we report on their identity, prevalence and potential infection strategy. Gill parasites were genetically and morphologically identified from collected specimens of Chiroteuthis calyx, Vampyroteuthis infernalis and Gonatus spp. In situ prevalence was estimated from video footage for C. calyx, Galiteuthis spp., Taonius spp. and Japetella diaphana, enabled by their transparent mantle tissue. The most common parasite was identified as Hochbergia cf. moroteuthensis, a protist of unresolved taxonomic ranking. We provide the first molecular data for this parasite and show a sister group relationship to the dinoflagellate genus Oodinium. Hochbergia cf. moroteuthensis was most commonly observed in adult individuals of all species and was sighted year round over the analyzed time period. In situ prevalence was highest in C. calyx (75%), followed by Galiteuthis spp. (29%), Taonius spp. (27%) and J. diaphana (7%). A second parasite, not seen on the in situ footage, but occurring within the gills of Gonatus berryi and Vampyroteuthis infernalis, could not be found in the literature or be identified through DNA barcoding. The need for further investigation is highlighted, making this study a starting point for unravelling ecological implications of the cephalopod-gill-parasite system in deep pelagic waters.

A remarkable new species of the genus Hydaticus from Madagascar, with an identification key for Malagasy species of the genus (Coleoptera: Dytiscidae: Dytiscinae)

Summary Hydaticus (Prodaticus) mangamanga n. sp. is described from a single sampling site in the south-eastern part of Madagascar Central Highlands, near Ranomafana. The new species is unique among the known species of the genus Hydaticus in that the last visible abdominal ventrite is strongly modified and differentiated between sexes, and is also quite unusual in paramere configuration. Analysis of partial CO1 sequences revealed that H. mangamanga belongs to the leander-group and is genetically close to the Malagasy region endemic H. inconspicuus Régimbart, 1895 stat. rev. with only around 1.5% of sequence divergence, providing the first instance of a sister-group relationship between two Hydaticus species endemic from the Malagasy region. However, morphologically these two species differ considerably. They are illustrated (habitus, structures, male genitalia) and compared in detail. Collecting circumstances for H. mangamanga are described and a map of its known distribution is provided. A lectotype is designated for H. inconspicuus; this name is re-established as valid for this species, and the name H. kolbei Branden, 1885 used in the recent literature is considered of doubtful identity. An identification key is provided for all Hydaticus (Prodaticus) species known from Madagascar, with accompanying illustrations of median lobes of aedeagus in lateral view.

A New Species in Notobitiella Hsiao in China Confirmed by Morphological and Molecular Data (Hemiptera: Heteroptera: Coreidae).

Simple SummaryPlenty of new species are published every year, but what if a new species could be erected as a new genus by the morphological characteristics of genitalia or a new species of an existing genus by the other morphological characteristics? Recently, we collected a new species of Coreidae facing this problem. The characteristics of genitalia between the new and existing species in Notobitiella (monotypic genus) were too different to compare with the difference among interspecies in tribe Cloresmini. It was reasonable to erect a new genus for this new species. However, considering the similarity between other characteristics, we decided to refer to the results of molecular data. Results showed that the genetic distance within the interspecific interval of the genus and the sister group relationship also supported that the new species should be included in the genus Notobitiella. Finally, a new species was confirmed, named Notobitiella bispina sp. nov. Our research highlighted how molecular data can be used to assist in species delimitation when encountering similar problems.To date, only one species of genus Notobitiella, N. elegans Hsiao, was found in Yunnan, China. Recently, we confirmed a new species, Notobitiella bispina sp. nov., by morphological and molecular data based on new specimens collected from Yunnan, China. The new species is morphologically similar to N. elegans except for the male genitalia and the sternum of the seventh abdominal segment of the female. The extraordinary difference of the genitalia between these two species inspired us to erect a new genus for this new species. However, considering their sister group relationship to other genera in tribe Cloresmini and the 12.56~12.64% genetic distance (meeting the interspecific genetic distance within genus of tribe Cloresmini) by a complete COI gene, this species was more reasonable as a new species of the genus Notobitiella, and the diagnosis of the genus was revised. The photos of the body and critical morphological characteristics for both male and female were provided for accurate identification.

Caucasoseris, a new genus of subtribe Chondrillinae (Asteraceae: Cichorieae) for the enigmatic Prenanthes abietina

A new genus, Caucasoseris, is established to accommodate Prenanthes abietina, a species of hitherto uncertain systematic position distributed in the western Caucasus and northeasternmost Turkey in montane conifer and mixed forests. Agreement has existed that the species belongs somewhere in the Crepidinae or Lactucinae but its morphological features do not match any genus and previous molecular phylogenetic analyses could not establish its sister group. This study provides additional micro- and macromorphological, palynological and anatomical data, and used a molecular phylogenetic sampling designed to ascertain its relationship. A sister group relationship with the Chondrillinae is inferred from the phylogenetic tree based on nrITS. In the plastid DNA tree, where the Chondrillinae are resolved as a clade nested inside the Crepidinae, the species is resolved further remote from the Chondrillinae clade and in a rather early diverging position of the Crepidinae. In agreement also with the anatomical and micro- and macromorphological findings, it is considered an orphan lineage with affinities to the Chondrillinae, best treated as a genus of its own. A key to the genera of the Chondrillinae including Caucasoseris is provided. Citation: Güzel M. E., Kilian N., Sennikov A. N., Coşkunçelebi K., Makbul S. & Gültepe M. 2022: Caucasoseris, a new genus of subtribe Chondrillinae (Asteraceae: Cichorieae) for the enigmatic Prenanthes abietina. – Willdenowia 52: 103–115. Version of record first published online on 16 April 2022 ahead of inclusion in April 2022 issue.

Relationships among Calibrachoa, Fabiana and Petunia (Petunieae tribe, Solanaceae) and a new generic placement of Argentinean endemic Petuniapatagonica.

Calibrachoa Cerv., Fabiana Ruiz & Pav., and Petunia Juss. form a clade within tribe Petunieae (Solanaceae). Phylogenetic studies of Petunieae, either as part of a family-wide analysis or focusing on the genera Calibrachoa and Petunia, have either left Fabiana unsampled or included only a single species. These studies have found conflicting relationships among the three genera with all three possible topologies obtained. Petuniapatagonica (Speg.) Millán, originally described in the genus Nierembergia Ruiz & Pav., is morphologically distinct within Petunia and geographically disjunct from other members of the genus. For the first time, in this study we include multiple species of Fabiana, Calibrachoa, and Petunia, including P.patagonica. Using three chloroplast DNA regions and the nuclear gene GBSSI, or “waxy,” our results provide strong support for a sister group relationship between Calibrachoa and Fabiana and for the placement of P.patagonica within Fabiana. Since there is already a species Fabianapatagonica Speg., we provide the new name Fabianaaustralis Alaria nom. nov. to replace Petuniapatagonica.

Comparison of mitogenomes of three Petalocephala species (Hemiptera: Cicadellidae: Ledrinae) and their phylogenetic analysis.

Ledrinae is a unique group of leafhoppers with a distinct appearance. Petalocephala is the largest Ledrinae genus that is difficult to identify except by dissecting the male genitals. To date, research on Ledrinae is relatively less compared with other leafhoppers. Therefore, to better understand this group, we sequenced and analyzed three complete Petalocephala mitochondrial genomes. We comparatively analyzed these general Petalocephala genomic features (including size, AT content, AT/GC skew, 13 protein-coding gene nucleotide compositions, etc.), and predicted 22 transferRNA secondary structures. We obtained highly consistent phylogenetic results within Cicadellidae based on mitogenomic data using the maximum likelihood and Bayesian methods. Our results showed that all subfamilies were monophyletic and had a high node support rate, and there was a sister group relationship between Ledrinae and all other leafhopper groups. Furthermore, treehoppers were found to originate from leafhoppers and showed sister group relationships with Megophthalminae. Within Ledrinae, all phylogenetic trees supporting phylogenetic relationships were as follows: ([P. dicondylica + P. gongshanensis] + [Tituria pyramidata + [Ledra auditura + P. gongshanensis]]) Based on the complete mitogenome phylogenetic analysis and the comparison of morphological characteristics, we propose that Petalocephala is not monophyletic.

3D-anatomy and systematics of cocculinid-like limpets (Gastropoda: Cocculiniformia): more data, some corrections, but still an enigma

New material and new methodologies substantially widen the anatomical knowledge on cocculinid limpets. We first provide 3D-anatomies of Fedikovella caymanensis and Teuthirostria cancellata based on serial sections. Both species differ in several major points (mainly the gill-type and several features of the alimentary tract) from typical cocculinids, accordingly they are classified in a new clade, Teuthirostriidae fam. nov. Specimens studied by McLean and Harasewych (LA County Mus Contrib Sci 453:1–33, 1995) under “Fedikovella beanii” probably represent another species new to science. Additional investigations of original (type) section series of Cocculina laevis Thiele, 1904 (type species of Paracocculina Haszprunar, 1987) and of Cocculina radiata Thiele, 1904 (type species of Coccocrater Haszprunar, 1987) imply some nomenclatorial revisions: Cocculina cervae Fleming, 1948 is designated as type species of Pedococculina gen. nov. Anatomical characters confirm the subsequent placement of Cocculina viminensis Rocchini, 1990 into Coccopigya Marshall, 1986, whereas the original generic status of the whale-fall inhabitant Cocculina craigsmithi McLean, 1992 is confirmed despite the unusual habitat. The latter species probably has symbiotic bacteria in the midgut gland; if so this might be due to the environmental and feeding conditions at whale cadavers or hydrothermal vents. Contrary to Lepetelloidea, the Cocculiniformia cannot be included in Vetigastropoda. Recent molecular data support a sistergroup relationship of Cocculiniformia with Neomphalida, and we add the phenotypic perspective on this so-called “Neomphaliones”-hypothesis. In particular, more phylogenomic data are needed to specify the position of Cocculinida among the rhipidoglossate Gastropoda.

Characterization of the complete mitogenome of brown-spotted locust, Cyrtacanthacris tatarica (Orthoptera: Acrididae: Cyrtacanthacridinae)

The complete mitochondrial genome of Cyrtacanthacris tatarica was firstly sequenced and analyzed. The circular mitogenome was 15,679 bp long, showing a bias of AT rich on the majority strand (42.34% of A, 29.99% of T, 11.19% of G, and 16.18% of C). It consisted of the typical 37 genes (13 protein-coding genes, two ribosomal RNA genes, and 22 transfer tRNA genes) and one longest non-coding region (called as control region). All PCGs used standard ATN initiation codons, and most PCGs were terminated with complete codons (TAA/TAG), apart from cox1 and nad5. Phylogenetic analyses based on the concatenated nucleotide sequences of PCGs supported that Cyrtacanthacridinae was monophyletic, and the sister group relationship between C. tatarica and Schistocerca gregaria gregaria was determined. Our results may provide molecular information for the genetic evolution and taxonomy of the acridid species.

Unraveling the evolutionary history of the snakefly family Inocelliidae (Insecta: Raphidioptera) through integrative phylogenetics.

Inocelliidae is one of the two extant families of the holometabolan order Raphidioptera (snakeflies), with the modern fauna represented by seven genera and 44 species. The evolutionary history of the family is little-known. Here we present the first phylogenetic and biogeographical analyses based on a worldwide sampling of taxa and datasets combined with morphological characters and mitochondrial genomes, aiming to investigate the intergeneric phylogeny and historical biogeography of Inocelliidae. The phylogenetic inference from the combined analysis of morphological and molecular data recovered the sister-group relationship between a clade of (Negha + Indianoinocellia) + Sininocellia and a clade of Fibla + the Inocellia clade (interiorly nested by Amurinocellia and Parainocellia). Amurinocellia stat.r. and Parainocellia stat.r. et emend.n. are relegated to subgeneric status within Inocellia, whereas a newly erected subgenus of Inocellia, Epinocellia subgen.n., accommodates the former Parainocellia burmana (U. Aspöck and H. Aspöck, 1968) plus a new species Inocellia (Epinocellia) weii sp.n. Further, the Inocellia crassicornis group constitutes the nominotypical subgenus Inocellia stat.n., but the Inocellia fulvostigmata group is paraphyletic. Diversification within Inocelliidae is distinguished by an Eocene divergence leading to extant genera and a Miocene radiation of species. A biogeographical scenario depicts how the diverse inocelliid fauna from East Asia could have originated from western North America via dispersal across the Beringia during the early Tertiary, and how the Miocene ancestors of Inocellia could have accomplished long-distance dispersals via the Tibet-Himalayan corridor or eastern Palaearctic to western Palaearctic. Our results shed new light specifically on the evolution of Inocelliidae and, in general, the Raphidioptera.

Chalarosthrix gen. nov., a new taxon of the Sphingothrix-Triathrix clade (Harpacticoida: Cletodidae) from the Province of Cortez, Eastern Mexican Pacific.

Seven species of four cletodid genera previously described or reported from Mexico (Cletodes, Enhydrosoma, Geehydrosoma, and Stylicletodes) and an undescribed genus presumably related to Sphingothrix and Triathrix, were found in sediment samples from a coastal system in north-western Mexico. The Bayesian analysis of 95 morphological characters of thirty-four cletodid genera revealed that the new genus, Chalarosthrix gen. nov., is closely related to Sphingothrix. The clade Sphingothrix-Chalarosthrix bears a sister group relationship with Triathrix. These three genera constitute a monophyletic group defined by the presence of a posterior chitinous extension of the cephalothorax with four sensillum-bearing socles, and the presence of a median tube-pore on the anal operculum. Other synapomorphies for Sphingothrix and Triathrix proposed by earlier researchers are re-evaluated upon the latest definition of the Cletodidae. Our analysis supports previous studies in that Sphingothrix can be objectively defined by i) the reduction of the distal outer seta of the last exopodal segment of the first swimming leg being at most as long as the subdistal outer spine, and ii) the distal inner seta of the same segment inclined outwards intersecting the distal outer element at its base. On the other hand, no (aut)apomorphies were detected for Triathrix. The new genus, Chalarosthrix gen. nov., is defined here by the apomorphic secondary loss of the inner element of the second endopodal segment of the first swimming leg. Some comments on the relationships of the new genus are given.