We present an updated checklist of native Mexican freshwater gastropods with data on their general distribution, hotspots of endemicity, threats, and for the first time, their estimated conservation status. The list contains 193 species, representing 13 families and 61 genera. Of these, 103 species (53.4%) and 12 genera are endemic to Mexico, and 75 species are considered local endemics because of their restricted distribution to very small areas. Using NatureServe Ranking, 9 species (4.7%) are considered possibly or presumably extinct, 40 (20.7%) are critically imperiled, 30 (15.5%) are imperiled, 15 (7.8%) are vulnerable and only 64 (33.2%) are currently stable. With 61 species in 21 genera, the Cochliopidae are the most diverse family, followed by the Planorbidae (37 species) and Pachychilidae (31). Pachychilus is the most species-rich genus with 30 species. Despite the high number of imperiled species (84), only 7 species (3.6%) are currently listed as endangered by the Mexican Secretariat of Environment and Natural Resources. We identified 3 hotspots and 2 potential centers of gastropod endemicity. Our research serves as a first step for determining priority areas for conservation of imperiled Mexican freshwater gastropods. A. Czaja et al. / Revista Mexicana de Biodiversidad 91 (2020): e912909 2 https://doi.org/10. 22201/ib.20078706e.2020.91.2909 ResumenSe presenta un listado actualizado de gasterópodos dulceacuícolas nativos de México con datos de su distribución general, hotspots de endemicidad, amenazas y, por primera vez, su estado de conservación estimado. La lista contiene 193 especies, 13 familias y 61 géneros. De éstas, 103 especies (53.4%) y 12 géneros son endémicos de México y 75 de estas especies se consideraron endémicas locales debido a su distribución restringida a áreas muy pequeñas. Usando NatureServe Ranking, consideramos 9 especies (4.7%) posiblemente o probablemente extintas, 40 (20.7%) en peligro crítico, 30 (15.5%) en peligro, 15 (7.8%) son vulnerables y solo 64 (33.2%) están estables actualmente. Con 61 especies en 21 géneros, Cochliopidae es la familia más diversa, seguida de Planorbidae (37 especies) y Pachychilidae (31). Pachychilus (Pachychilidae) con 30 especies, es el género más rico en especies de los gasterópodos dulceacuícolas mexicanos. A pesar del alto número de caracoles en peligro (84), solo 7 (3.6%) están actualmente catalogados en peligro por la Secretaría de Medio Ambiente y Recursos Naturales de México. Identificamos 3 hotspots y 2 centros potenciales de endemicidad. Los resultados servirán como un primer paso para determinar las áreas prioritarias para la conservación de los gasterópodos mexicanos amenazados.

BackgroundThe aim of this study was to detect and molecularly identify Rickettsia spp. in Rhipicephalus sanguineus (sensu lato) collected from free-roaming dogs in 30 communities from five municipalities in the south of Coahuila State, northern Mexico, where Rocky Mountain spotted fever is endemic.MethodsIn total, 60 dogs from each municipality were examined for engorged ticks. DNA was isolated from tick pools and conventional PCR assays targeting the 23S-5S ribosomal RNA intergenic spacer and outer membrane protein (ompA) gene of Rickettsia spp. were performed.ResultsAll ticks (n = 1238) were morphologically identified as R. sanguineus (s.l.). Six pools (each with six engorged females) from four municipalities were positive to Rickettsia spp. DNA sequencing and phylogenetic analyses confirmed the presence of R. rickettsii and R. rhipicephali in R. sanguineus (s.l.) in these ticks.ConclusionsThis study confirms the presence of R. rickettsii and R. rhipicephali in R. sanguineus (s.l.) from stray dogs in the south of Coahuila. This suggests that stray dogs may play a role in the inter-municipal dissemination of infected ticks in this region. Further research is required to assess whether ticks from stray dogs could serve as good indicators for the molecular xenomonitoring of R. rickettsii in this region. Considering that R. sanguineus (s.l.) is a proven vector of R. rickettsii in Mexico, increased awareness regarding permanent tick control in dogs is warranted.

The general bacterial microbiota of the soft tick Ornithodoros turicata found on Bolson tortoises (Gopherus flavomarginatus) were analyzed using next generation sequencing. The main aims of the study were to establish the relative abundance of bacterial taxa in the tick, and to document the presence of potentially pathogenic species for this tortoise, other animals, and humans. The study was carried-out in the Mapimi Biosphere Reserve in the northern-arid part of Mexico. Bolson tortoises (n = 45) were inspected for the presence of soft ticks, from which 11 tortoises (24.4%) had ticks in low loads (1–3 ticks per individual). Tick pools (five adult ticks each) were analyzed through 16S rRNA V3–V4 region amplification in a MiSeq Illumina, using EzBioCloud as a taxonomical reference. The operational taxonomic units (OTUs) revealed 28 phyla, 84 classes, 165 orders, 342 families, 1013 genera, and 1326 species. The high number of taxa registered for O. turicata may be the result of the variety of hosts that this tick parasitizes as they live inside G. flavomarginatus burrows. While the most abundant phyla were Proteobacteria, Actinobacteria, and Firmicutes, the most abundant species were two endosymbionts of ticks (Midichloria-like and Coxiella-like). Two bacteria documented as pathogenic to Gopherus spp. were registered (Mycoplasma spp. and Pasteurella testudinis). The bovine and ovine tick-borne pathogens A. marginale and A. ovis, respectively, were recorded, as well as the zoonotic bacteria A. phagocytophilum,Coxiella burnetii, and Neoehrlichia sp. Tortoises parasitized with O. turicata did not show evident signs of disease, which could indicate a possible ecological role as a reservoir that has yet to be demonstrated. In fact, the defense mechanisms of this tortoise against the microorganisms transmitted by ticks during their feeding process are still unknown. Future studies on soft ticks should expand our knowledge about what components of the microbiota are notable across multiple host–microbe dynamics. Likewise, studies are required to better understand the host competence of this tortoise, considered the largest terrestrial reptile in North America distributed throughout the Chihuahuan Desert since the late Pleistocene.

The community of oral bacteria of the Bolson tortoise, Gopherus flavomarginatus, was determined at the Reserva de la Biosfera Mapimí, México by massive sequencing. During 2015, samples of 5 males and 5 females apparently healthy were collected; DNA was extracted, V3-V4 16S rRNA regions were amplified, sequencing was carried out with Illumina, and EzBioCloud was used as the reference taxonomic base. No significant difference was observed in the oral microbiota between sexes. Proteobacteria, Actinobacteria, and Firmicutes were the dominant phyla, as well as the class Gammaproteobacteria, and the order Pasteurellales. Pasteurellaceae, Moraxellaceae, and Micrococcaceae were the most abundant families. Among taxa potentially pathogenic for tortoises, we documented molecularly the presence of Mycoplasma, and Pasteurella testudinis in G. flavomarginatus; both are considered as possible participants in causing upper respiratory disease in other Gopherus species. Genus Bergeyella is reported for the first time in the oral cavity of a reptile; this zoonotic bacteria had only been reported as part of the oral microbiome of canines and felines. This information provides an oral bacterial diversity baseline for this species that will contribute to and improve current conservation and management plans.

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