Congeneric Species Research Articles

A new species of Metafruticicola (Gastropoda, Hygromiidae) from the Aegean Archipelago and new anatomical and distributional data on some congeneric species

Metafruticicola is a diverse land snail genus inhabiting the north-eastern Mediterranean region from S Albania to Israel. In this study, we describe Metafruticicola kavafis sp. nov., a new species for science from Kasos Island. We also focus on the reproductive system of steno-endemic species and subspecies of the genus from small islands of the Aegean Archipelago, whose anatomy was previously completely unknown. These species are M. crassicosta, M. pieperi, M. coartata gemina and M. nicosiana conciliatrix. For the latter subspecies, only the outlines of the genitalia were previously given. Additionally, we investigated in detail for the first time the genital anatomy of M. nicosiana nicosiana from Cyprus. Hitherto, information on the genital apparatus of this subspecies was based on sparse data derived from sexually immature specimens. These new anatomical data contribute to a plethora of controversies concerning the subgeneric division of Metafruticicola, which was based solely on conchological features and especially the microsculpture of the teleoconch. We suggest that the current subgeneric division of the genus should be abandoned.

DNA Barcoding and Molecular Phylogenetics Revealed a New Cryptic Bamboo Aphid Species of the Genus Takecallis (Hemiptera: Aphididae)

Takecallis nigroantennatus Wieczorek sp. nov. (Hemiptera: Aphididae), associated with the cold hardy bamboo variety Fargesia spp. (Bambusoideae), is described and illustrated along with a key to species of the genus Takecallis. The results of a mitochondrial COI (DNA barcoding) and nuclear elongation factor 1 (EF1α) gene sequences, which confirm the genetic difference of the new taxon from the other congeneric species, are provided. The possible way of introduction of this species to Europe is discussed with its new locality from Belgium.

Factors contributing to mitogenome size variation and a recurrent intracellular DNA transfer in Melastoma

BackgroundMitogenome sizes of seed plants vary substantially even among closely related species, which are often related to horizontal or intracellular DNA transfer (HDT or IDT) events. However, the mechanisms of this size variation have not been well characterized.ResultsHere we assembled and characterized the mitogenomes of three species of Melastoma, a tropical shrub genus experiencing rapid speciation. The mitogenomes of M. candidum (Mc), M. sanguineum (Ms) and M. dodecandrum (Md) were assembled to a circular mapping chromosome of 391,595 bp, 395,542 bp and 412,026 bp, respectively. While the mitogenomes of Mc and Ms showed good collinearity except for a large inversion of ~ 150 kb, there were many rearrangements in the mitogenomes between Md and either Mc or Ms. Most non-alignable sequences (> 80%) between Mc and Ms are from gain or loss of mitochondrial sequences. Whereas, between Md and either Mc or Ms, non-alignable sequences in Md are mainly chloroplast derived sequences (> 30%) and from putative horizontal DNA transfers (> 30%), and those in both Mc and Ms are from gain or loss of mitochondrial sequences (> 80%). We also identified a recurrent IDT event in another congeneric species, M. penicillatum, which has not been fixed as it is only found in one of the three examined populations.ConclusionsBy characterizing mitochondrial genome sequences of Melastoma, our study not only helps understand mitogenome size evolution in closely related species, but also cautions different evolutionary histories of mitochondrial regions due to potential recurrent IDT events in some populations or species.

A new species of Chicomurex (Gastropoda, Muricidae) from the Saya de Malha Bank, Western Indian Ocean

Chicomurex kozlovi sp. nov., collected from the Saya de Malha Bank in the Mascarene Plateau, Western Indian Ocean, is described and illustrated. The holotype was sampled at a depth of 200 m during the expedition of R/V Gordy in 1989, while paratypes 1 and 2 were trawled from a depth of 100-200 m by research-fishery boats during the eighties. Chicomurex kozlovi sp. nov. is compared with morphologically similar congeneric species.

A histological analysis of coloration in the Peruvian mimic poison frog (Ranitomeya imitator).

Aposematism continues to be a phenomenon of central interest in evolutionary biology. The life history of the mimic poison frog, Ranitomeya imitator, relies heavily on aposematism. In order for aposematic signals to be effective, predators must be able to learn to avoid the associated phenotype. However, in R. imitator, aposematism is associated with four different color phenotypes that mimic a complex of congeneric species occurring across the mimic frog's geographic range. Investigations of the underlying mechanics of color production in these frogs can provide insights into how and why these different morphs evolved. We used histological samples to examine divergence in the color production mechanisms used by R. imitator to produce effective aposematic signals across its geographic range. We measured the coverage of melanophores and xanthophores (the area covered by chromatophores divided by total area of the skin section) in each color morph. We find that morphs that produce orange skin exhibit a higher coverage of xanthophores and lower coverage of melanophores than those that produce yellow skin. In turn, morphs that produce yellow skin exhibit a higher coverage of xanthophores and lower coverage of melanophores than those that produce green skin. Generally, across the morphs, a high ratio of xanthophores to melanophores is associated with colors of brighter spectral reflectance. Together, our results contribute to the understanding of color production in amphibians and document divergence in the histology of a species that is subject to divergent selection associated with aposematism.

Genome skimming as an efficient tool for authenticating commercial products of the pharmaceutically important Paris yunnanensis (Melanthiaceae)

BackgroundParis yunnanensis (Melanthiaceae) is a traditional Chinese medicinal plant of significant pharmaceutical importance. Due to previous taxonomic confusion, a congeneric species, Paris liiana, has been mistaken for P. yunnanensis and cultivated on a large scale, leading to the mixing of commercial products (i.e., seedlings and processed rhizomes) of P. yunnanensis with those of P. liiana. This may have adverse effects on quality control in the standardization of P. yunnanensis productions. As the lack of PCR amplifiable genomic DNA within processed rhizomes is an intractable obstacle to the authentication of P. yunnanensis products using PCR-based diagnostic tools, this study aimed to develop a PCR-free method to authenticate commercial P. yunnanensis products, by applying genome skimming to generate complete plastomes and nrDNA arrays for use as the molecular tags.ResultsBased on a dense intraspecies sampling of P. liiana and P. yunnanensis, the robustness of the proposed authentication systems was evaluated by phylogenetic inferences and experimental authentication of commercial seedling and processed rhizome samples. The results indicate that the genetic criteria of both complete plastomes and nrDNA arrays were consistent with the species boundaries to achieve accurate discrimination of P. yunnanensis and P. liinna. Owing to its desirable accuracy and sensitivity, genome skimming can serve as an effective and sensitive tool for monitoring and controlling the trade of P. yunnanensis products.ConclusionThis study provides a new way to solve the long-standing problem of the molecular authentication of processed plant products due to the lack of PCR amplifiable genomic DNA. The proposed authentication system will support quality control in the standardization of P. yunnanensis products in cultivation and drug production. This study also provides molecular evidence to clarify the long-standing taxonomic confusion regarding the species delimitation of P. yunnanensis, which will contribute to the rational exploration and conservation of the species.

Preference and performance of the generalist aphid Myzus persicae on closely and distantly related plant species

AbstractThe ability of herbivorous insects to discriminate suitable host plants for the development of their progeny is not homogenous. Herbivores with broader diets show weaker correlation between oviposition preference and offspring performance in comparison with specialist insects. The neural constraints hypothesis postulates that due to neural limitation, generalist insects would have greater difficulty in processing a large number of stimuli from diverse host plants. Under this framework, it is expected that generalists would be more efficient in discriminating suitable plants when faced with more similar stimuli from closely related plants (simplified environment), and less efficient when faced with more diverse stimuli from unrelated plants (complex environment). In this study, we evaluated this in the generalist aphid Myzus persicae (Sulzer) (Hemiptera: Aphididae). Preference was evaluated as the aphid's ability to discriminate between congeneric plant species or between plants from different families. The congeneric host plants were the cultivated potato, Solanum tuberosum L., the wild potato, Solanum commersonii Dunal, tomato, Solanum lycopersicum L., and eggplant, Solanum melongena L. (Solanaceae). The plant species of different families used were spinach, Spinacia oleracea L. (Amaranthaceae), squash, Cucurbita maxima Duchesne (Cucurbitaceae), and basil, Ocimum basilicum L. (Lamiaceae). Performance was evaluated as the population growth in one generation on whole‐plant conditions and on excised leaves. The results showed positive correlations between settlement and larviposition preferences and the performance of M. persicae for all comparisons between unrelated plant species. Positive correlations between preference and performance were also observed for two of the three comparisons between congeneric plants. These results indicate that M. persicae can efficiently discriminate between suitable plants for their progeny regardless of the degree of relatedness of the plants, which is at odds with the neural constraints hypothesis. The results contribute to the knowledge of host selection mechanisms in generalist herbivores, particularly in an underrepresented insect group.

Morphological and molecular description of Dictyocaulus xanthopygus sp. nov. (Nematoda: Trichostrongyloidea) from the Manchurian wapiti Cervus elaphus xanthopygus.

Dictyocaulus xanthopygus sp. nov. (Nematoda: Trichostrongyloidea) was isolated from the lungs of the Manchurian wapiti in Primorsky kray, Russia. The newly described species exhibits morphological characteristics of Dictyocaulus but is distinct from congeneric species based on morphological (lengths of body and esophagus, distances from the anterior end to nerve ring and to excretory pore, the thickness of the buccal capsule, etc.) and molecular features. High levels of genetic divergence as well as Bayesian phylogenetic analyses based on 18S rRNA nuclear and cox1 mitochondrial genes supported the independence of Dictyocaulus xanthopygus sp. nov. Secondary structures of helix 39 of 18S rRNA were identical, while ES9 adjacent to the helix has a unique conformation for newly described worms. Energy-efficient conformational rearrangements of rRNA secondary structures can be applicable in studies on the pathogenesis, epidemiology, taxonomy and evolutionary biology of parasites. Additionally, bracketed dichotomous keys to six valid species of Dictyocaulus were prepared.

A Drone-Powered Deep Learning Methodology for High Precision Remote Sensing in California’s Coastal Shrubs

Wildland conservation efforts require accurate maps of plant species distribution across large spatial scales. High-resolution species mapping is difficult in diverse, dense plant communities, where extensive ground-based surveys are labor-intensive and risk damaging sensitive flora. High-resolution satellite imagery is available at scales needed for plant community conservation across large areas, but can be cost prohibitive and lack resolution to identify species. Deep learning analysis of drone-based imagery can aid in accurate classification of plant species in these communities across large regions. This study assessed whether drone-based imagery and deep learning modeling approaches could be used to map species in complex chaparral, coastal sage scrub, and oak woodland communities. We tested the effectiveness of random forest, support vector machine, and convolutional neural network (CNN) coupled with object-based image analysis (OBIA) for mapping in diverse shrublands. Our CNN + OBIA approach outperformed random forest and support vector machine methods to accurately identify tree and shrub species, vegetation gaps, and communities, even distinguishing two congeneric shrub species with similar morphological characteristics. Similar accuracies were attained when applied to neighboring sites. This work is key to the accurate species identification and large scale mapping needed for conservation research and monitoring in chaparral and other wildland plant communities. Uncertainty in model application is associated with less common species and intermixed canopies.

Survey and Molecular Characterization of Sarcocystidae protozoa in Wild Cricetid Rodents from Central and Southern Chile.

In Chile, studies of parasites from the family Sarcocystidae (Apicomplexa) have mostly been related to domestic animals. We aimed to assess the presence of Sarcocystidae taxa in cricetid rodents from Central and Southern Chile. We studied 207 rodents, encompassing six species, from 13 localities. We isolated DNA from tissue samples, amplified the Sarcocystidae 18S rRNA gene with polymerase chain reaction, and performed phylogenetic analyses using maximum likelihood and Bayesian inferences. In addition, we examined blood smears and performed histological studies in organs from Sarcocystidae DNA-positive animals. Three specimens were DNA-positive and three genotypes were retrieved and named: Sarcocystis sp. P61, related to Sarcocystis strixi, was detected in two Abrothrix olivacea. Toxoplasmatinae gen. sp. P99 was retrieved from those same two specimens, and was related to Toxoplasma and other genera, although it branched independently. Besnoitia sp. R34 was detected in one Abrothrix hirta, and was clustered with congeneric species associated with rodents. No protozoa were found during microscopic studies; thus, it was not possible to confirm parasitic interactions rather than accidental encounters. However, the close relatedness of the retrieved genotypes to parasites of rodents supports the hypothesis of host-parasite associations. All three genotypes are suggested as potential new taxa, including a putative new genus.

Four new species of Anenterotrema Stunkard, 1938 (Digenea: Dicrocoellidae) infecting phyllostomid bats in the Peruvian Amazon.

During a research of digeneans (Platyhelminthes: Trematoda) infecting leaf-nosed bats (Chiroptera: Phyllostomidae) from the Kawsay Biological Station in Madre de Dios, southeastern Peru, four new species were described based on light and scanning electron microscopy (SEM): Anenterotrema paramegacetabulum n. sp. from the seba's short-tailed bat Carollia perspicillata Linnaeus, A. hastati n. sp., A. kawsayense n. sp., and A. peruense n. sp. from the greater spear-nosed bat Phyllostomus hastatus (Pallas). Anenterotrema paramegacetabulum n. sp. differs from all congeners by having a terminal oral sucker, a transversely elongated ventral sucker without clamp-shaped, and by having the testes located immediately posterior to ventral sucker. Anenterotrema hastati n. sp. is easily differentiated from the other congeneric species by having an almost clamp-shaped oral sucker, well-developed cirrus sac, a bilobulated seminal receptacle, and a group of well-developed unicellular glands located anterolateral to cirrus sac. Anenterotrema kawsayense n. sp. is characterized by possessing protuberances on the anterior margin of the oral sucker. Anenterotrema peruense n. sp. is mainly characterized by having the testes located principally anterior to ventral sucker and the cirrus sac located perpendicular to midline of the body. The present finding brings to 12, the number of known species of Anenterotrema. A key to the species of Anenterotrema Stunkard, 1938 is provided.

Description of a new species of the genus Xyrosaris Meyrick (Lepidoptera: Yponomeutidae) from the Far East of Russia with notes on congeneric species.

A new species, Xyrosaris insularis sp. n., was found in the Far East of Russia. Most of the specimens were obtained through the rearing of larvae that fed on Celastrus orbiculatus Thunb. (Celastraceae). The genetic distances between the mtCOI sequences in X. insularis and congeneric species are in the range 1.2-13.9%. Minimal genetic distance (1.2%) was discovered between new species and X. lichneuta Meyrick from Shaanxi (China), which is lower than the standard mtCOI barcoding threshold of 2% for species delineation, but both taxa differ well in the genital morphology. The description of a new species is accompanied by illustrations of variations in the pattern, by the genitalia of both sexes, and by larva on its host plant.

New Insight into the Genus Cladocroce (Porifera, Demospongiae) Based on Morphological and Molecular Data, with the Description of Two New Species

During scientific expeditions in Indonesia and Vietnam, several sponge specimens belonging to the genus Cladocroce were collected. The integration of morphological and molecular analyses, incorporating species delimitation models (ABGD, ASAP, and bPTP) and phylogenetic approaches using three molecular markers (COI, 28S, and 18S–ITS1–5.8S–ITS2–28S), allowed us to discriminate three congeneric species. Two of these species (C. burapha and C. pansinii sp. nov.) were supported by morphological and molecular data, whereas a third species (C. lamellata sp. nov.) was delimited by morphological data only. We formally describe two new species, C. pansinii sp. nov. and C. lamellata sp. nov. C. aculeata is a newly recorded species for Indonesia and the first documented finding after the original description. The re-examination of the type material of C. burapha, and indirectly the molecular approach, allowed us to confirm that C. burapha lives in sympatry with C. pansinii sp. nov. in Vietnam and with C. lamellata in Indonesia. Thanks to these findings, we relocated the paratype of C. burapha to the new species described here, i.e., C. pansinii sp. nov.

Host species differences in the thermal mismatch of host-parasitoid interactions.

Extreme high temperatures associated with climate change can affect species directly, and indirectly through temperature-mediated species interactions. In most host-parasitoid systems, parasitization inevitably kills the host, but differences in heat tolerance between host and parasitoid, and between different hosts, may alter their interactions. Here, we explore the effects of extreme high temperatures on the ecological outcomes - including, in some rare cases, escape from the developmental disruption of parasitism - of the parasitoid wasp, Cotesia congregata, and two co-occurring congeneric larval hosts, Manduca sexta and M. quinquemaculata. Both host species had higher thermal tolerance than C. congregata, resulting in a thermal mismatch characterized by parasitoid (but not host) mortality under extreme high temperatures. Despite parasitoid death at high temperatures, hosts typically remain developmentally disrupted from parasitism. However, high temperatures resulted in a partial developmental recovery from parasitism (reaching the wandering stage at the end of host larval development) in some host individuals, with a significantly higher frequency of this partial developmental recovery in M. quinquemaculata than M. sexta. Hosts species also differed in their growth and development in the absence of parasitoids, with M. quinquemaculata developing faster and larger at high temperatures relative to M. sexta. Our results demonstrate that co-occurring congeneric species, despite shared environments and phylogenetic histories, can vary in their responses to temperature, parasitism, and their interaction, resulting in altered ecological outcomes.

HABITAT SELECTION OF Marmosops incanus (LUND, 1841) (DIDELPHIMORPHIA, DIDELPHIDAE) IN THE SERRA DOS ÓRGÃOS NATIONAL PARK, ATLANTIC FOREST, SOUTHEAST BRAZIL

Habitat selection is one of the mechanisms responsible for allowing species coexistence and, therefore, local richness of communities. This study investigates microhabitat selection by the opossum, Marmosops incanus, in a forested area in the Brazilian Atlantic Forest. We measured microhabitat variables related to vegetation structure and inferred M. incanus abundance as a measure of habitat use. Eight microhabitat variables were measured in each trap station: litter, herbaceous and woody stems, rock outcropping, canopy cover, foliar vertical obstruction at three heights (FOV), and number of fallen trunks. Based on a correlation matrix, we selected four microhabitat variables (litter, rock outcropping cover, FOV, and number of fallen trunks) and performed a Poisson regression using the selected variables and M. incanus abundance. Litter and rock outcropping cover were positively related to abundance, thus representing the habitat characteristics selected by the species. We infer that litter represents a source of food items, since it can support an abundant fauna of macroinvertebrates, especially arthropods. Rock outcroppings can be used as shelter and protection against predators. Other studies have recorded M. incanus using habitat in a unique way, either by changing the frequency of ground/understory use, or habitats with high/few herbaceous and litter cover, as the habitat varied from restinga to fragmented forests. Different habitat selection patterns were observed in areas where M. incanus and M. paulensis are sympatric, or Gracilinanus microtarsus, both of which have comparable size and ecology. We suppose the selection patterns recorded in this study are a result of the absence of a congener species in the study area. It may allow M. incanus to use more frequently areas where near-ground strata are clear and highly covered with litter. It remains to be evaluated if habitat simplification leads to behavior homogenization.

Closely related aliens lead to greater extinction risk

Alien species are considered a major driver of extinction risk. Preventing high-impact aliens from being introduced is more necessary than ever to mitigate the current biodiversity crisis. Invasive species risk assessments look at the characteristics of potential invaders but rarely consider how different they are from the native residents that they might threaten. Therefore, we tested whether the impacts of an alien species on a native species can be predicted using the pairwise phylogenetic distance (PPD) between them. Specifically, we analysed whether the PPD of 1407 pairs of native–invasive alien plants is related to the extinction risk of the native plants. We showed that natives threatened by close alien relatives have a significantly higher extinction risk, especially on oceanic islands. This finding argues for consideration of PPD, or at least the presence of congeneric or confamilial native species, in risk assessment of potential impacts of newly introduced alien species and priorization of management of already naturalized alien species.

Characterization of the complete chloroplast genome of Gypsophila huashanensis Y. W. Tsui & D. Q. Lu, an endemic herb species in China

Gypsophila huashanensis Y. W. Tsui & D. Q. Lu (Caryophyllaceae) is an endemic herb species to the Qinling Mountains in China. In this study, we characterized its whole plastid genome using the Illumina sequencing platform. The complete plastid genome of G. huashanensis is 152,457 bp in length, including a large single-copy DNA region of 83,476 bp, a small single-copy DNA region of 17,345 bp, and a pair of inverted repeat DNA sequences of 25,818 bp. The genome contains 130 genes comprising 85 protein-coding genes, 37 tRNA genes, and eight rRNA genes. Evolutionary analysis showed that the non-coding regions of Caryophyllaceae exhibit a higher level of divergence than the exon regions. Gene site selection analysis suggested that 11 coding protein genes (accD, atpF, ndhA, ndhB, petB, petD, rpoCl, rpoC2, rps16, ycfl, and ycf2) have some sites under protein sequence evolution. Phylogenetic analysis showed that G. huashanensis is most closely related to the congeneric species G. oldhamiana. These results are very useful for studying phylogenetic evolution and species divergence in the family Caryophyllaceae.

Genomic Insights into Adaptation to Karst Limestone and Incipient Speciation in East Asian Platycarya spp. (Juglandaceae).

When challenged by similar environmental conditions, phylogenetically distant taxa often independently evolve similar traits (convergent evolution). Meanwhile, adaptation to extreme habitats might lead to divergence between taxa that are otherwise closely related. These processes have long existed in the conceptual sphere, yet molecular evidence, especially for woody perennials, is scarce. The karst endemic Platycarya longipes and its only congeneric species, Platycarya strobilacea, which is widely distributed in the mountains in East Asia, provide an ideal model for examining the molecular basis of both convergent evolution and speciation. Using chromosome-level genome assemblies of both species, and whole-genome resequencing data from 207 individuals spanning their entire distribution range, we demonstrate that P. longipes and P. strobilacea form two species-specific clades, which diverged around 2.09 million years ago. We find an excess of genomic regions exhibiting extreme interspecific differentiation, potentially due to long-term selection in P. longipes, likely contributing to the incipient speciation of the genus Platycarya. Interestingly, our results unveil underlying karst adaptation in both copies of the calcium influx channel gene TPC1 in P. longipes. TPC1 has previously been identified as a selective target in certain karst-endemic herbs, indicating a convergent adaptation to high calcium stress among karst-endemic species. Our study reveals the genic convergence of TPC1 among karst endemics and the driving forces underneath the incipient speciation of the two Platycarya lineages.

Genomic Insights into Adaptation to Karst Limestone and Incipient Speciation in East Asian Platycarya spp. (Juglandaceae).

When challenged by similar environmental conditions, phylogenetically distant taxa often independently evolve similar traits (convergent evolution). Meanwhile, adaptation to extreme habitats might lead to divergence between taxa that are otherwise closely related. These processes have long existed in the conceptual sphere, yet molecular evidence, especially for woody perennials, is scarce. The karst endemic Platycarya longipes, and its only congeneric species, P. strobilacea, which is widely distributed in the mountains in East Asia, provide an ideal model for examining the molecular basis of both convergent evolution and speciation. Using chromosome-level genome assemblies of both species, and whole genome resequencing data from 207 individuals spanning their entire distribution range, we demonstrate that P. longipes and P. strobilacea form two species-specific clades, which diverged around 2.09 million years ago. We find an excess of genomic regions exhibiting extreme interspecific differentiation, potentially due to long-term selection in P. longipes, likely contributing to the incipient speciation of the genus Platycarya. Interestingly, our results unveil underlying karst adaptation in both copies of the calcium influx channel gene TPC1 in P. longipes. TPC1 has previously been identified as a selective target in certain karst-endemic herbs, indicating a convergent adaptation to high calcium stress among karst-endemic species. Our study reveals the genic convergence of TPC1 among karst endemics, and the driving forces underneath the incipient speciation of the two Platycarya lineages.

Troglonectes canlinensis sp. nov. (Teleostei: Nemacheilidae), a New Troglomorphic Loach from Guangxi, China.

A new species of the genus Troglonectes is described based on specimens from a karst cave in Andong Town, Xincheng County, Liuzhou City, Guangxi, China. Troglonectes canlinensis sp. nov. can be distinguished from its congener species by the following combination of characteristics: eye degenerated into a black spot; whole body covered by scales, except for the head, throat, and abdomen; incomplete lateral line; forked caudal fin; 8-10 gill rakers on the first gill arch; 13-14 branched caudal fin rays; 8-9 branched dorsal fin rays; 5-6 anal fin rays; 9-10 pectoral fin rays; upper adipose keel depth mostly 1/2 of the caudal peduncle depth; and caudal fin forked.