Phylogenetic analysis of Blaberoidea reveals non-monophyly of taxa and supports the creation of multiple new subfamilies.

The superfamily Blaberoidea is a highly species-rich group of cockroaches. High-level blaberoidean phylogenetics are still under debate owing to variable taxon sampling and incongruence between mitochondrial and nuclear evolution, as well as different methods used in various phylogenetic studies. We here present a phylogenetic analysis of Blaberoidea based on a dataset combining the mitochondrial genome with two nuclear markers from representatives of all recognized families within the superfamily. Our results support the monophyly of Blaberiodea, which includes Ectobiidae s.s. (=Ectobiinae), Pseudophyllodromiidae, Nyctiboridae, Blattellidae s.s. (=Blattellinae) and Blaberidae. Ectobiidae s.s. was recovered as sister to the remaining Blaberoidea in all inferences. Pseudophyllodromiidae was paraphyletic with respect to Anaplectoidea + Malaccina. Blattellidae s.s. excluding Anaplectoidea + Malaccina formed a monophyletic group that was sister to Blaberidae. Based on our results, we propose a revised classification for Blaberoidea: Anaplectoidinae subfam.nov. and Episorineuchora gen.nov., and two new combinations at species level within Pseudophyllodromiidae; Rhabdoblattellinae subfam.nov., Calolamprodinae subfam.nov., Acutirhabdoblatta gen.nov., as well as new combinations for three species within Blaberidae. Ancestral state reconstructions based on four morphological characters allow us to infer that the common ancestor of blaberoid cockroaches is likely to be a species with characteristics similar to those found in Ectobiidae, that is, front femur Type B, arolium present, abdomen with a visible gland and male genital hook on the left side.

Vicariance and dispersal events inferred from mitochondrial genomes and nuclear genes (18S, 28S) shaped global Cryptocercus distributions.

Cryptocercus Scudder, a genus of wingless, subsocial cockroaches, has low vagility but exhibits a disjunct distribution in eastern and western North America, and in China, South Korea and the Russian Far East. This distribution provides an ideal model for testing hypotheses of vicariance through plate tectonics or other natural barriers versus dispersal across oceans or other natural barriers. We sequenced 45 samples of Cryptocercus to resolve phylogenetic relationships among members of the genus worldwide. We identified four types of tRNA rearrangements among samples from the Qin-Daba Mountains. Our maximum-likelihood and Bayesian phylogenetic trees, based on mitochondrial genomes and nuclear genes (18S, 28S), strongly supported six major lineages of Cryptocercus, which displayed a clear geographical distribution pattern. We used Bayesian molecular dating to estimate the evolutionary timescale of the genus, and reconstructed Cryptocercus ancestral ranges using statistical dispersal-vicariance analysis (S-DIVA) in RASP. Two dispersal events and six vicariance events for Cryptocercus were inferred with high support. The initial vicariance event occurred between American and Asian lineages at 80.5 Ma (95% credibility interval: 60.0-104.7 Ma), followed by one vicariance event within the American lineage 43.8 Ma (95% CI: 32.0-57.5 Ma), and two dispersal 31.9 Ma (95% CI: 25.8-39.5 Ma), 21.7 Ma (95% CI: 17.3-27.1 Ma) plus four vicariance events c. 29.3 Ma, 27.2 Ma, 24.8 Ma and 16.7 Ma within the Asian lineage. Our analyses provide evidence that both vicariance and dispersal have played important roles in shaping the distribution and diversity of these woodroaches.

Evidence for reduced immune gene diversity and activity during the evolution of termites.

The evolution of biological complexity is associated with the emergence of bespoke immune systems that maintain and protect organism integrity. Unlike the well-studied immune systems of cells and individuals, little is known about the origins of immunity during the transition to eusociality, a major evolutionary transition comparable to the evolution of multicellular organisms from single-celled ancestors. We aimed to tackle this by characterizing the immune gene repertoire of 18 cockroach and termite species, spanning the spectrum of solitary, subsocial and eusocial lifestyles. We find that key transitions in termite sociality are correlated with immune gene family contractions. In cross-species comparisons of immune gene expression, we find evidence for a caste-specific social defence system in termites, which appears to operate at the expense of individual immune protection. Our study indicates that a major transition in organismal complexity may have entailed a fundamental reshaping of the immune system optimized for group over individual defence.

The Complete Mitogenome of the Wood-Feeding Cockroach Cryptocercus meridianus (Blattodea: Cryptocercidae) and Its Phylogenetic Relationship among Cockroach Families.

In this study, the complete mitochondrial genome of Cryptocercus meridianus was sequenced. The circular mitochondrial genome is 15,322 bp in size and contains 13 protein-coding genes, two ribosomal RNA genes (12S rRNA and 16S rRNA), 22 transfer RNA genes, and one D-loop region. We compare the mitogenome of C. meridianus with that of C. relictus and C. kyebangensis. The base composition of the whole genome was 45.20%, 9.74%, 16.06%, and 29.00% for A, G, C, and T, respectively; it shows a high AT content (74.2%), similar to the mitogenomes of C. relictus and C. kyebangensis. The protein-coding genes are initiated with typical mitochondrial start codons except for cox1 with TTG. The gene order of the C. meridianus mitogenome differs from the typical insect pattern for the translocation of tRNA-SerAGN, while the mitogenomes of the other two Cryptocercus species, C. relictus and C. kyebangensis, are consistent with the typical insect pattern. There are two very long non-coding intergenic regions lying on both sides of the rearranged gene tRNA-SerAGN. The phylogenetic relationships were constructed based on the nucleotide sequence of 13 protein-coding genes and two ribosomal RNA genes. The mitogenome of C. meridianus is the first representative of the order Blattodea that demonstrates rearrangement, and it will contribute to the further study of the phylogeny and evolution of the genus Cryptocercus and related taxa.

A global molecular phylogeny and timescale of evolution for Cryptocercus woodroaches.

Cryptocercus is a genus of sub-social wood-feeding cockroaches that represents the sister group to the eusocial termites. We generated mitochondrial (12S+16S rRNA, COII), nuclear (28S rRNA) and Blattbacterium endosymbiont (16S+23S rRNA) sequence data for 8 new Chinese species, and combined these with previously available data to undertake the most extensive analysis of phylogenetic relationships within the genus to date. As expected, phylogenetic relationships among Blattabacterium strains were found to be congruent with those of their hosts. Three major clades were found to exist in Asian populations, one representing taxa from the Hengduan mountains in Southwestern China, a second including taxa from Russia, Korea, Northeastern China, and Yunnan in the Hengduan Mountains, and a third including taxa from the Qinling Mountains and Daba Mountains in Central China. A molecular dating analysis using 7 termite fossils to calibrate the molecular clock indicated that the divergence of American and Asian Cryptocercus occurred 55.09Ma (41.55-72.28Ma 95% CI), and that the radiations of American and Asian taxa occurred 28.48Ma (20.83-37.95Ma 95% CI) and 20.97Ma (15.78-27.21Ma 95% CI) respectively. Reconstruction of ancestral geographic distributions using S-DIVA suggested Cryptocercus was originally distributed across both continents, as opposed to ancestral migration of Cryptocercus from one continent to the other. The last common ancestor of Asian Cryptocercus was inferred to have existed in Central China. An examination of male chromosome numbers in Asian Cryptocercus showed that diploid numbers vary from 2n=15 to 2n=41, and indicates the presence of eight new species. Our study represents the most comprehensive phylogenetic and biogeographic study yet performed for this important group of cockroaches.

Six new species of Margattea Shelford, 1911 (Blaberoidea, Pseudophyllodromiidae, Neoblattellini) from China.

Six Margattea species are established and described: three are cryptic species, namely, M.parabisignata Li & Che, sp. nov., M.semicircularis Li & Che, sp. nov., and M.forcipata Li & Che, sp. nov. They are distinguished from known species M.bisignata, M.spinifera, and M.paratransversa by their male genitalia with the aid of molecular species delimitation method (ABGD) using COI as the molecular marker. The other three new species are M.pedata Li & Che, sp. nov., M.undulata Li & Che, sp. nov., and M.bisphaerica Li & Che, sp. nov. Morphological and genitalia photographs of these new species of Margattea, as well as a key to the species of Margattea from China, are provided.

Discovery of five new species of Allacta from Yunnan and Hainan, China (Blattodea, Pseudophyllodromiidae).

We examined new Allacta materials from Yunnan and Hainan Province, China, and discovered new species using both morphological and molecular species delimitation (ABGD) methods. Five new species are described: A.bifolium Li & Wang, sp. nov., A.hemiptera Li & Wang, sp. nov., A.lunulara Li & Wang, sp. nov., A.redacta Li & Wang, sp. nov., and A.unicaudata Li & Wang, sp. nov. All five species are placed under the hamifera species group. An updated key and checklist of Allacta species from China are provided.

A new genus of the tribe Parahiraciini from China, with notes on the tribe (Hemiptera: Fulgoroidea: Issidae).

The new issid taxon, Folifemurum duplicatum gen. et sp. nov. from China is described and illustrated. This description includes external morphology of the adult, and structures of the male and female genitalia. The genus is placed in the tribe Parahiraciini. A diagnosis of Folifemurum gen.nov. is given and is compared to the related genus Neodurium Fennah. In addition, a key to all genera of the tribe is provided.

Three new species of Scalida (Blattodea: Blattellidae) from Yunnan, China.

Three new Scalida species from Yunnan are reported: Scalida hamata Qiao & Che sp. nov., Scalida spinosa Qiao & Che sp. nov., Scalida ramiformis Qiao & Che sp. nov.. Morphological descriptions of the new species, including the male genitalia, are provided along with detailed photographs. A list and a key to species of Scalida in the world are provided.

Two new genera (Vittiblatta gen. nov. and Planiblatta gen. nov.) of Blattinae (Blattodea, Blattidae) from Southwest China and the discovery of chirally dimorphic male genitalia in Vittiblattapunctata sp. nov.

This study examines Blattinae samples from Southwest China collected in recent years. Based on morphological characters, we establish two genera, Vittiblattagen. nov. and Planiblattagen. nov., and describe four new species, Vittiblattapunctata Luo & Wang, sp. nov., Vittiblattaferruginea Luo & Wang, sp. nov., Vittiblattaundulata Luo & Wang, sp. nov., and Planiblattacrassispina Luo & Wang, sp. nov. These two new genera resemble Periplaneta s.s., but are easily distinguished from it and other genera of Blattinae by morphological characters (genital sclerite L4C). Our results indicate that sclerites L4C and R1G of male genitalia might be important in species delimitation of Blattinae. In addition, chiral dimorphism is found in male genitalia of Vittiblattapunctata sp. nov.

Redescription of Periplanetaarabica (Bey-Bienko, 1938) (Blattodea, Blattidae), with a comparative analysis of three species of Periplaneta Burmeister, 1838 (sensu stricto).

The blattid cockroach Periplanetaarabica (Bey-Bienko, 1938) has been poorly understood since its original description. In this study, male and female (including nymph) of P.arabica are paired using DNA barcoding, and their morphological characters (including both external characteristics and genitalia) are described. A detailed comparative morphological study of this species and the closely related Periplanetaamericana (Linnaeus, 1758) and Periplanetalateralis Walker, 1868 was carried out to explore phylogenetically relevant characters.

A new species of Bundoksia Lucañas, 2021 with comments on its subfamilial placement, based on morphological and molecular data.

One new species of Bundoksia Lucañas, 2021 from China is described. We construct a haplotype network from 21 COI sequences to display the relationships amongst populations of Bundoksialongissima sp. nov., mainly from Hainan Island, Yunnan Province and Guangxi Province, China. For the first time, we provide the details of female genitalia in addition to the known external morphology and male genitalia of the genus. Six molecular markers (12S, 16S, 18S, 28S, COI and COII) from a total of 38 samples, including three samples of Bundoksialongissima sp. nov., are used to reconstruct phylogenetic trees using Maximum Likelihood (ML) and Bayesian Inference (BI) to assess the phylogenetic affinities of Bundoksia. Photographs of the morphology and a key to the three Bundoksia species are also provided.

Three cryptic Anaplecta (Blattodea, Blattoidea, Anaplectidae) species revealed by female genitalia, plus seven new species from China.

Morphological characteristics, including male and female genitalia, combined with DNA barcodes were used to identify 470 Anaplecta specimens sampled from China. Ten Anaplecta species are new to science, including three cryptic species: A.paraomei Zhu & Che, sp. nov., A.condensa Zhu & Che, sp. nov., and A.longihamata Zhu & Che, sp. nov., which are distinguished mainly by their female genitalia. The other seven new species are as follows: A.bicruris Zhu & Che, sp. nov., A.spinosa Zhu & Che, sp. nov., A.ungulata Zhu & Che, sp. nov., A.anomala Zhu & Che, sp. nov., A.serrata Zhu & Che, sp. nov., A.bombycina Zhu & Che, sp. nov., and A.truncatula Zhu & Che, sp. nov. This study illustrates that differences in female genitalia can be used to distinguish among species of Anaplecta. The female genitalia of 19 Chinese Anaplecta species are described and illustrated in this paper.

Exploring the diversity of Eupolyphaga Chopard, 1929 (Blattodea, Corydioidea): species delimitation based on morphology and molecular analysis.

Eupolyphaga Chopard, 1929 is a cockroach genus mainly endemic to China. In this study, the species diversity of this genus is further explored through morphology and molecular analysis. Four species are described new to science: Eupolyphagamiracidia Qiu, sp. nov., Eupolyphagaudenostyla Qiu, sp. nov., Eupolyphagareducta Qiu, sp. nov., and Eupolyphagasimila Qiu, sp. nov. New knowledge on some known species is added, including new distribution records and characteristics of females. Forty-five COI sequences were newly sequenced and a molecular species delimitation analysis was performed using ABGD method. Eighteen molecular operational taxonomic units were obtained by ABGD analysis, which are nearly consistent with the results of morphological delimitation.

Establishment of two new Anaplecta species (Blattodea, Blattoidea, Anaplectidae) based on morphological and COI data with an additional description of Anaplectafurcata Deng & Che, 2020.

Based on morphological characteristics, including male and female genitalia, combined with DNA barcodes, two new species, Anaplectacircinalis Deng & Che, sp. nov. and Anaplectabihamata Deng & Che, sp. nov., are described in detail. Additional information on the female genitalia of Anaplectafurcata Deng & Che, 2020 is also provided. Photographs of external morphology and caudal anatomy of these species, as well as a key to the Chinese Anaplecta species, are provided.

Species delimitation of Margattea cockroaches from China, with seven new species (Blattodea, Ectobiidae, Pseudophyllodromiinae).

Nearly 450 Margattea specimens were collected from 27 locations in China and their morphology was examined. Then 68 Margattea COI sequences were obtained and used to carry out phylogenetic analyses as well as species delimitation analyses using General Mixed Yule Coalescent (GMYC), Automatic Barcode Gap Discovery (ABGD), and Poisson Tree Processes (bPTP). GMYC analysis resulted in 21 molecular operational taxonomic units (MOTUs) (confidence interval: 20-22), which was completely consistent with the result of the bPTP. There were 15 MOTUs using the ABGD method. The number of MOTUs was slightly different from the assigned morphospecies (16). As to the incongruence between molecular and morphological results, we checked the specimens again and made sure that most morphological differences were determined to be intraspecific differences (except the difference between M. angusta and M. mckittrickae), although a large genetic distance existed. Finally, 16 Margattea species from China were defined in this study, of which, seven new species are established, i.e. Margattea deltodonta J-J He & Z-Q Wang, sp. nov., Margattea cuspidata J-J He & Z-Q Wang, sp. nov., Margattea caudata J-J He & Z-Q Wang, sp. nov., Margattea paratransversa J-J He & Z-Q Wang, sp. nov., Margattea disparilis J-J He & Z-Q Wang, sp. nov., Margattea transversa J-J He & Z-Q Wang, sp. nov., and Margattea bicruris J-J He & Z-Q Wang, sp. nov.

Exploring the relationship of Homalosilpha and Mimosilpha (Blattodea, Blattidae, Blattinae) from a morphological and molecular perspective, including a description of four new species.

This study utilized six genes (12S, 16S, 18S, 28S, COII and H3) from a total of 40 samples to construct maximum likelihood (ML) and Bayesian inference (BI) phylogenetic trees in order to infer the relationships between the morphologically similar genera Homalosilpha Stål, 1874 and Mimosilpha Bey-Bienko, 1957. The phylogenetic analysis showed the two genera have a close relationship and were recovered as sister groups based on ML and BI analyses. Four new species are described among these samples, i.e., Homalosilpha obtusangula sp. nov., Homalosilpha recta sp. nov., Homalosilpha alba sp. nov. and Homalosilpha clavellata sp. nov. based on morphological and COI data. A key to the worldwide Homalosilpha is provided.

New record of Cyrtonotula Uvarov, 1939 (Blaberidae, Epilamprinae) from China, with three new species based on morphological and COI data.

The genus Cyrtonotula Uvarov, 1939 (Blaberidae, Epilamprinae) is recorded for the first time from Hainan Island, China. Three new species, Cyrtonotula epunctata Wang & Wang, sp. nov., C. maculosa Wang & Wang, sp. nov., and C. longialata Wang & Wang, sp. nov., are described based on morphological data and a molecular analysis using Automatic Barcode Gap Discovery (ABGD). Additional barcode data of blaberid species, including these three new species, are provided to facilitate future species identification. Morphological photographs and habitat photos of these new species, as well as a key to the known species, are provided.

Species diversity revealed in Sigmella Hebard, 1929 (Blattodea, ectobiidae) based on morphology and four molecular species delimitation methods.

Cockroaches are one of the major decomposers involved in biogeochemical cycles. Cockroaches have an amazing amount of diversity, but most of them remain unknown due to the shortage of the trained taxonomists and the limitations of morphology-based identification. We obtained 49 COI sequences (including 42 novel sequences) and 32 novel 28S sequences for 5 Sigmella morphospecies collected from 11 localities. Three are new to science: Sigmella digitalis sp. nov., Sigmella exserta sp. nov. and Sigmella normalis sp. nov. Based on four species delimitation methods (ABGD, GMYC, BINs and bPTP), a total of 6 molecular operational taxonomic units (MOTUs) were recovered for 5 morphospecies. These were then confirmed by tree building methods using COI and combined data (COI and 28S). We detected more than one MOTU in the morphospecies S. digitalis sp. nov., which can indicate genetic diversity. Detailed morphological evidence for each MOTU is provided to confirm these slight variations and we conclude that natural barriers are likely the main cause of genetic diversity.