Water Beetles as Models in Ecology and Evolution.

Beetles have colonized water many times during their history, with some of these events involving extensive evolutionary radiations and multiple transitions between land and water. With over 13,000 described species, they are one of the most diverse macroinvertebrate groups in most nonmarine aquatic habitats and occur on all continents except Antarctica. A combination of wide geographical and ecological range and relatively accessible taxonomy makes these insects an excellent model system for addressing a variety of questions in ecology and evolution. Work on water beetles has recently made important contributions to fields as diverse as DNA taxonomy, macroecology, historical biogeography, sexual selection, and conservation biology, as well as predicting organismal responses to global change. Aquatic beetles have some of the best resolved phylogenies of any comparably diverse insect group, and this, coupled with recent advances in taxonomic and ecological knowledge, is likely to drive an expansion of studies in the future.

Entomological Collections in the Age of Big Data.

With a million described species and more than half a billion preserved specimens, the large scale of insect collections is unequaled by those of any other group. Advances in genomics, collection digitization, and imaging have begun to more fully harness the power that such large data stores can provide. These new approaches and technologies have transformed how entomological collections are managed and utilized. While genomic research has fundamentally changed the way many specimens are collected and curated, advances in technology have shown promise for extracting sequence data from the vast holdings already in museums. Efforts to mainstream specimen digitization have taken root and have accelerated traditional taxonomic studies as well as distribution modeling and global change research. Emerging imaging technologies such as microcomputed tomography and confocal laser scanning microscopy are changing how morphology can be investigated. This review provides an overview of how the realization of big data has transformed our field and what may lie in store.

Transoceanic Stepping-stones between Cretaceous waterfalls? The enigmatic biogeography of pantropical Oocyclus cascade beetles.

Beetles have colonized freshwater habitats multiple times throughout their evolutionary history. Some of these aquatic lineages are associated exclusively with waterfall-like habitats, often with modified morphologies to cope with their unusual way of life. The historical biogeography of such cascade beetle lineages has been shown to strongly reflect ancient tectonic events. We focus on the pantropical genus Oocyclus of which species dwell in waterfalls and associated habitats. We infer the first molecular phylogeny of Oocyclus using a dataset of seven gene fragments. We recover a well resolved phylogenetic hypothesis, with a monophyletic Oocyclus divided in three genetically well-differentiated subclades which correspond to geography. Comparative dating analyses across Hydrophilidae based on ten fossil calibrations recover a Cretaceous origin for the genus. Based on a comprehensive suite of ancestral range analyses, we suggest a unique pattern with an origin in Southeast Asia followed by the successive colonization of India and the Neotropics via transoceanic stepping-stone dispersal. Diversification rate analyses support a scenario in which old Oocyclus lineages diversified slowly with a homogeneous rate regime. Waterfall beetle radiations are ancient and remarkably track Earth's paleogeological history, shedding light on intricate patterns of macroevolution.

Molecular phylogeny of the aquatic beetle family Noteridae (Coleoptera: Adephaga) with an emphasis on data partitioning strategies.

The first molecular phylogenetic hypothesis for the aquatic beetle family Noteridae is inferred using DNA sequence data from five gene fragments (mitochondrial and nuclear): COI, H3, 16S, 18S, and 28S. Our analysis is the most comprehensive phylogenetic reconstruction of Noteridae to date, and includes 53 species representing all subfamilies, tribes and 16 of the 17 genera within the family. We examine the impact of data partitioning on phylogenetic inference by comparing two different algorithm-based partitioning strategies: one using predefined subsets of the dataset, and another recently introduced method, which uses the k-means algorithm to iteratively divide the dataset into clusters of sites evolving at similar rates across sampled loci. We conducted both maximum likelihood and Bayesian inference analyses using these different partitioning schemes. Resulting trees are strongly incongruent with prior classifications of Noteridae. We recover variant tree topologies and support values among the implemented partitioning schemes. Bayes factors calculated with marginal likelihoods of Bayesian analyses support a priori partitioning over k-means and unpartitioned data strategies. Our study substantiates the importance of data partitioning in phylogenetic inference, and underscores the use of comparative analyses to determine optimal analytical strategies. Our analyses recover Noterini Thomson to be paraphyletic with respect to three other tribes. The genera Suphisellus Crotch and Hydrocanthus Say are also recovered as paraphyletic. Following the results of the preferred partitioning scheme, we here propose a revised classification of Noteridae, comprising two subfamilies, three tribes and 18 genera. The following taxonomic changes are made: Notomicrinae sensu n. (= Phreatodytinae syn. n.) is expanded to include the tribe Phreatodytini; Noterini sensu n. (= Neohydrocoptini syn. n., Pronoterini syn. n., Tonerini syn. n.) is expanded to include all genera of the Noterinae; The genus Suphisellus Crotch is expanded to include species of Pronoterus Sharp syn. n.; and the former subgenus Sternocanthus Guignot stat. rev. is resurrected from synonymy and elevated to genus rank.

A revision of the Lutrochidae (Coleoptera) of Venezuela, with description of six new species.

The species of Lutrochidae occurring in Venezuela are revised. The only previously recorded species, Lutrochus acuminatus Grouvelle, is redescribed and a lectotype is designated. Lutrochus vestitus Sharp, is recorded from Venezuela and French Guiana for the first time. Six new species Lutrochus gustafsoni n. sp., L. cauraensis n. sp., L. maldonadoi n. sp., L. meridaensis n. sp., L. minutus n. sp., and L. violaceus n. sp. are described. Notes on habitat and habits for most species are provided, as well as a key to the eight species of Lutrochidae occurring in Venezuela. The family is reported from hygropetric habitats for the first time.

New species and new records of the hygropetric water beetle genus Oocyclus Sharp from South America (Coleoptera: Hydrophilidae).

Three new species of Oocyclus Sharp, 1882 are described from tropical South America: O. maluz sp. n. (Venezuela), O. miza sp. n. (Venezuela), and O. brunneus sp. n. (Bolivia). New distributional records are provided for O. andinus Short & García, O. coromoto Short & García (newly recorded from Suriname), O. floccus Short & García (newly recorded from Guyana and Suriname), O. iguazu (Oliva), O. meridensis Short & García, O. petra Short & García (newly recorded from Guyana and Suriname), O. trio Short & Kadosoe (newly recorded from Guyana), O. trujillo Short & García, and O. yubai Clarkson & Short (newly recorded from Paraguay). Updates to the keys of the Brazilian and Venezuelan Oocyclus species are provided.

Ciimaerocyon gen. nov., a morphologically aberrant myrmecophilous genus of water scavenger beetle (Coleoptera: Hydrophilidae: Sphaeridiinae).

Anew hydrophilid genus Chimaerocyon gen. nov. containing two species, C. shimadai sp. nov. (Malaysia: Pahang) and C. sumatranus sp. nov. (Indonesia: Sumatra), is described. Specimens of C. shimadai were collected from brood cells in anest of Pheidole singaporensis Özdikmen, 2010. The biology of C. sumatranus remains unknown. A molecular phylogeny based on four genes (cox1, cox2, 18S and 28S) supports the placement of the genus as deeply nested within the Cercyon-group of the tribe Megasternini. This position is supported by the subdistal position of the median spur in the hind wing (unique to Megasternini) and the presence of sucking disc on male maxilla (unique for Megastemini+Sphaeridiini). The remaining external morphology differs substantially from other representatives of Megasternini. The hypothesis that the aberrant morphology of Chimaerocyon gen. nov. is a consequence of myrmecophily is discussed.

Revision of the Neotropical water scavenger beetle genus Novochares Girón & Short (Coleoptera, Hydrophilidae, Acidocerinae).

The water scavenger beetle genus Novochares Girón & Short, 2021 is revised using a combination of adult morphological and DNA sequence data. Thirty-eight new species are described: Novocharesaperitosp. nov. (Bolivia), N.bacasp. nov. (Brazil, Ecuador, Peru, Suriname), N.bidenssp. nov. (Brazil), N.bisinuatussp. nov. (Brazil), N.clavierisp. nov. (Brazil, French Guiana, Peru), N.dantasp. nov. (Venezuela), N.dentatussp. nov. (Ecuador, Venezuela), N.dicranospathussp. nov. (Peru), N.duosp. nov. (Brazil, French Guiana, Guyana, Suriname, Venezuela), N.fernandezaesp. nov. (Brazil, Peru, Venezuela), N.florifersp. nov. (Brazil), N.furcatussp. nov. (Brazil), N.garciaisp. nov. (Venezuela), N.garfosp. nov. (Brazil), N.geminussp. nov. (Brazil), N.kawsaysp. nov. (Ecuador, Peru), N.latussp. nov. (Brazil), N.minorsp. nov. (Peru, Suriname, Venezuela), N.mojenossp. nov. (Bolivia), N.murasp. nov. (Brazil), N.orchissp. nov. (Brazil, French Guiana, Suriname), N.pastinumsp. nov. (Ecuador), N.pertusussp. nov. (Brazil), N.piaroasp. nov. (Venezuela), N.pilatussp. nov. (Venezuela), N.pumesp. nov. (Venezuela), N.punctatostriatussp. nov. (Brazil, French Guiana, Guyana, Peru, Suriname), N.quadrispinussp. nov. (Brazil, Guyana, Suriname), N.spanglerisp. nov. (Peru), N.tambopatensesp. nov. (Peru), N.tenedorsp. nov. (Guyana, Venezuela), N.triangularissp. nov. (Bolivia, Brazil, Paraguay), N.tridentissp. nov. (Brazil), N.trifurcatussp. nov. (Peru), N.unguissp. nov. (Bolivia, Peru), N.xingusp. nov. (Brazil), and N.yanomamisp. nov. (Venezuela), N.yorasp. nov. (Peru). One new synonym is proposed: N.carmona (Short, 2005) syn. nov. was determined to be a junior subjective synonym of N.chaquensis (Fernández, 1982). Novocharesinornatus (d'Orchymont, 1926) is considered incertae sedis. Updated distributions and new records are provided for most previously described species in the genus. Novocharessallaei (Sharp, 1882) is considered native to the USA (Florida) and not an introduced species as previously suggested. Novochares now contains 52 species and spans the entire Neotropical region from Mexico to Argentina, including the Caribbean islands.

ResumenEl género de escarabajos acuáticos detritívoros Novochares Girón & Short, 2021, se revisa usando una combinación de datos morfológicos de los adultos y secuencias de ADN. Se describen 38 especies nuevas: Novocharesaperitosp. nov. (Bolivia), N.bacasp. nov. (Brasil, Ecuador, Perú, Surinam), N.bidenssp. nov. (Brasil), N.bisinuatussp. nov. (Brasil), N.clavierisp. nov. (Brasil, Guyana Francesa, Perú), N.dantasp. nov. (Venezuela), N.dentatussp. nov. (Ecuador, Venezuela), N.dicranospathussp. nov. (Perú), N.duosp. nov. (Brasil, Guyana, Guyana Francesa, Surinam, Venezuela), N.fernandezaesp. nov. (Brasil, Perú, Venezuela), N.florifersp. nov. (Brasil), N.furcatussp. nov. (Brasil), N.garciaisp. nov. (Venezuela), N.garfosp. nov. (Brasil), N.geminussp. nov. (Brasil), N.kawsaysp. nov. (Ecuador, Perú), N.latussp. nov. (Brasil), N.minorsp. nov. (Perú, Surinam, Venezuela), N.mojenossp. nov. (Bolivia), N.murasp. nov. (Brasil), N.orchissp. nov. (Brasil, Guyana Francesa, Surinam), N.pastinumsp. nov. (Ecuador), N.pertusussp. nov. (Brasil), N.piaroasp. nov. (Venezuela), N.pilatussp. nov. (Venezuela), N.pumesp. nov. (Venezuela), N.punctatostriatussp. nov. (Brasil, Guyana, Guyana Francesa, Perú, Surinam), N.quadrispinussp. nov. (Brasil, Guyana, Surinam), N.spanglerisp. nov. (Perú), N.tambopatensesp. nov. (Perú), N.tenedorsp. nov. (Guyana, Venezuela), N.triangularissp. nov. (Bolivia, Brasil, Paraguay), N.tridentissp. nov. (Brasil), N.trifurcatussp. nov. (Perú), N.unguissp. nov. (Bolivia, Perú), N.xingusp. nov. (Brasil), and N.yanomamisp. nov. (Venezuela), N.yorasp. nov. (Perú). Se propone una nueva sinonimia: N.carmona (Short, 2005) syn. nov. se determinó como sinónimo subjetivo posterior de N.chaquensis (Fernández, 1982). Novocharesinornatus (d'Orchymont, 1926) se considera incertae sedis. Se proveen distribuciones actualizadas y nuevos registros para la mayoría de las especies descritas previamente en el género. Novocharessallaei (Sharp, 1882) es considerada nativa en los Estados Unidos de América (Florida) y no como una especie potencialmente introducida como se afirmaba previamente. Novochares ahora contiene 52 especies y se extiende a lo largo de toda la región neotropical, desde México hasta Argentina, incluyendo las islas del Caribe.

A review of the Oocyclus Sharp of Ecuador with description of 12 new species (Coleoptera: Hydrophilidae: Laccobiini).

The species of the hygropetric water scavenger beetle genus Oocyclus Sharp, 1882 are reviewed for Ecuador. The genus has not previously been reported from the country. Twelve new species are described: O. ancho sp. n., O. ankas sp. n., O. bellus sp. n., O. kichwa sp. n., O. lepidus sp. n., O. packha sp. n., O. radiatus sp. n., O. rupestris sp. n., O. sumak sp. n., O. ustulatus sp. n., O. yantzaza sp. n., and O. zamora sp. n. One previously described species is newly reported for Ecuador: O. sharpi Short & Perkins 2004. There is at least one additional species that is part of a species complex that includes O. morgani García-Hernández, 2009 from Colombia and O. trujillo Short & García, 2010 from Venezuela. One new synonymy is proposed: the Venezuelan species O. zulianus Short & García, 2010 syn. n. is placed as a junior subjective synonym of O. sharpi Short & Perkins, 2004. A key to all described species known from the Andes region of South America is provided.

New species and new distributional records of the hygropetric water scavenger beetle genus Oocyclus Sharp (Coleoptera: Hydrophilidae) from the Guiana Shield.

The species of the water scavenger beetle genus Oocyclus Sharp are reviewed for the Guiana Shield region of South America. Seven species are recorded, including one here described as new: Oocyclus paraiso sp. n. from the Brazilian state of Pará. New records of previously described species are also reported for Brazil, French Guiana, Guyana, and Suriname. The aedeagus of O. coromoto Short & García is illustrated for the first time. As with all other known members of the genus, all Guiana Shield species are hygropetric habitat specialists. A key to the Oocyclus of the Guiana Shield is provided.

Next generation synthetic memory via intercepting recombinase function.

Here we present a technology to facilitate synthetic memory in a living system via repurposing Transcriptional Programming (i.e., our decision-making technology) parts, to regulate (intercept) recombinase function post-translation. We show that interception synthetic memory can facilitate programmable loss-of-function via site-specific deletion, programmable gain-of-function by way of site-specific inversion, and synthetic memory operations with nested Boolean logical operations. We can expand interception synthetic memory capacity more than 5-fold for a single recombinase, with reconfiguration specificity for multiple sites in parallel. Interception synthetic memory is ~10-times faster than previous generations of recombinase-based memory. We posit that the faster recombination speed of our next-generation memory technology is due to the post-translational regulation of recombinase function. This iteration of synthetic memory is complementary to decision-making via Transcriptional Programming - thus can be used to develop intelligent synthetic biological systems for myriad applications.

Safety and predictors of the success of lumbar punctures performed by a medicine procedure service.

BACKGROUND: Medicine procedure services (MPS) increasingly perform bedside procedures, including lumbar punctures (LPs). Success rates and factors associated with LP success performed by MPS have not been well described. OBJECTIVE: We identified patients undergoing LP by an MPS September 2015 to December 2020. We identified demographic and clinical factors, including patient position, body mass index (BMI), use of ultrasound, and trainee participation. We performed multivariable analysis to identify factors associated with LP success and complications. MAIN OUTCOME AND MEASURES: We identified 1065 LPs among 844 patients. Trainees participated in 82.2%; ultrasound guidance was used in 76.7% of LPs. The overall success rate was 81.3% with 7.8% minor and 0.1% major complications. A minority of LPs were referred to radiology (15.2%) or were traumatic (11.1%). In multivariable analysis, BMI > 30 kg/m2 (odds ratio [OR] 0.32, 95% confidence interval [CI] 0.21-0.48), prior spinal surgery (OR 0.50, 95% CI 0.26-0.87), and Black race (OR 0.62, 95% CI 0.41-0.95) were associated with decreased odds of successful LP; trainee participation (OR 2.49, 95% CI 1.51-4.12) was associated with increased odds. Ultrasound guidance (OR 0.53, 95% CI 0.31-0.89) was associated with lower odds of traumatic LP. RESULTS: In a large cohort of patients undergoing LP by an MPS, we identified high success and low complication rates. Trainee participation was associated with increased odds of success, while obesity, prior spinal surgery, and Black race were associated with decreased odds of success. Ultrasound guidance was associated with lower odds of a traumatic LP. Our data may help proceduralists in planning and assist in shared decision-making.

Revision of the water scavenger beetle genus Notionotus Spangler, 1972 in the Neotropical Region (Coleoptera, Hydrophilidae, Enochrinae).

The Neotropical species of the water scavenger beetle genus Notionotus Spangler, 1972 are revised using an integrative taxonomic approach combining morphology with DNA sequence data from two genes. Support exists for four putative species groups into which 18 species are placed, including twelve that are described here as new: N.bicolor sp. nov. (Suriname), N.bifidus sp. nov. (Venezuela), N.brunbadius sp. nov. (Brazil), N.garciae sp. nov. (Brazil), N.giraldoi sp. nov. (Brazil), N.insignitus sp. nov. (Venezuela), N.juma sp. nov. (Brazil), N.parvus sp. nov. (Suriname), N.patamona sp. nov. (Guyana), N.peruensis sp. nov. (Peru), N.retusus sp. nov. (Guyana), and N.vatius sp. nov. (Brazil). Four new synonymies are created: N.shorti Queney syn. nov. is found to be conspecific with N.dilucidus Queney; N.edibethae García syn. nov., N.nucleus Perkins syn. nov., and N.perijanus García syn. nov. are found to be conspecific with N.tricarinatus Perkins. New records are provided for all previously described species except N.mexicanus Perkins. Within the Neotropical region, the range of the genus is greatly expanded and now known from as far south as Bolivia and the Brazilian state of Mato Grosso do Sul. While a few species are found in hygropetric habitats, most are associated with the margins of forested streams. Genitalia and habitus images are provided for nearly all species, as well as a key to the four species groups.

ResumenLas especies de escarabajos acuáticos detritívoros neotropicales del género Notionotus Spangler, 1972 son revisadas usando taxonomía integrativa, combinando morfología con datos de secuencias de ADN para dos genes. Se encontró soporte para cuatro grupos de especies conformados por 18 especies, incluyendo 12 que son aquí descritas como nuevas: N.bicolor sp. nov. (Suriname), N.bifidus sp. nov. (Venezuela), N.brunbadius sp. nov. (Brazil), N.garciae sp. nov. (Brazil), N.giraldoi sp. nov. (Brazil), N.insignitus sp. nov. (Venezuela), N.juma sp. nov. (Brazil), N.parvus sp. nov. (Suriname), N.patamona sp. nov. (Guyana), N.peruensis sp. nov. (Peru), N.retusus sp. nov. (Guyana), N.vatius sp. nov. (Brazil). Se sinonimizan cuatro especies: N.shorti Queney syn. nov. se considera conespecífico con N.dilucidus Queney; N.edibethae García syn. nov., N.nucleus Perkins syn. nov., y N.perijanus García syn. nov. son conespecíficos con N.tricarinatus Perkins. Nuevos registros son provistos para todas las especies previamente descritas excepto para N.mexicanus Perkins. Hasta el momento, en la región neotropical, el rango de distribución del género es ampliamente expandido, se conoce desde el Sur de Bolivia hasta el estado brasileño de Mato Grosso do Sul. Si bien algunas especies son encontradas en hábitats higropétricos, la mayoría de ellas están asociadas a las orillas de arroyos boscosos. Se proveen imágenes del hábito dorsal y genitalia para la mayoría de las especies, al igual que la clave para los cuatro grupos de especies.

New species and new distributional records of the hygropetric water scavenger beetle genus Oocyclus Sharp (Coleoptera, Hydrophilidae) from the Brazilian Shield.

Nine new species of the water scavenger beetle genus Oocyclus Sharp, 1882 are described from the Brazilian Shield: O. ecolab sp. n., O. espinhacu sp. n., O. giganteus sp. n., O. humboldti sp. n., O. lacia sp. n., O. ovalis sp. n., O. sulcatus sp. n., O. thrixdiastematus sp. n., and O. thysanus sp. n. New locality records are provided for four species previously known from Brazil: O. rotundus Clarkson Short, 2012, O. pilosus Jordo, Clarkon Ferreira-Jr, 2018, O. xanthus Clarkson Short, 2012 and O. yubai Clarkson Short, 2012. All species are associated with rock-face seepages such as wet rocks, waterfalls, and seepages. An updated key to the Brazilian species of Oocyclus is provided.

Review of the New World Notomicrus Sharp (Coleoptera, Noteridae) I: Circumscription of species groups and review of the josiahi group with description of a new species from Brazil.

The New World species of the minute aquatic beetle genus Notomicrus Sharp compose a much greater diversity than their Old World congeners, with 14 of the 17 known Notomicrus species occurring in the Neotropics. A recent phylogenetic study recovered four primary New World species groups and found that there are a number of undescribed species across all of these main lineages. Here, we provide a taxonomic key to these New World species groups, including two described species that we currently do not place in any group ("incertae sedis" species), complete with images and illustrations of diagnostic characters and taxonomic notes including a list of known species in each group. This work provides a scaffold for further planned taxonomic revisions within the genus. In addition, we review the first of the four New World groups, the josiahi species group and describe one new taxon, N. interstinctus sp. nov. from northern Brazil. Provided are descriptions, habitus images and illustrations of diagnostic characters.

The Acidocerinae (Coleoptera, Hydrophilidae): taxonomy, classification, and catalog of species.

The cosmopolitan subfamily Acidocerinae (Coleoptera: Hydrophilidae) is one of the largest and most taxonomically challenging lineages of water scavenger beetles. Recent phylogenetic studies have substantially advanced our understanding of acidocerine relationships but also illuminated the twin challenges of poorly delineated generic concepts and a classification broadly incompatible with the phylogeny. Here, these two challenges are addressed by providing a comprehensive synthesis and taxonomic tools for the Acidocerinae, including (1) a brief history and the current state of acidocerine classification, (2) a review of acidocerine ecology and collection methods, (3) the current knowledge of larval and fossil acidocerines, (4) a morphological primer on characters of taxonomic and systematic importance within the lineage, (5) a key to the world genera of Acidocerinae, (6) diagnoses, habitus, and aedeagal images, distribution maps, and summary of knowledge for each of the 23 extant genera in the subfamily, and (7) a complete annotated taxonomic catalog including the published distributions, synonyms, and references for all described 541 acidocerine species recognized as of 1 April 2021. The following nomenclatural acts are proposed to bring the phylogeny and classification into alignment: Colossochares gen. nov. is established to accommodate two African species previously described as Helochares (s. str.); Novochares gen. nov. is newly established to accommodate 15 Neotropical species previously included in Helochares (s. str.); the remaining Helochares subgenera Helocharimorphus Kuwert syn. nov. and Hydrobaticus MacLeay syn. nov. are synonymized with Helochares Mulsant. Peltochares Régimbart sensu nov. is redefined to include eight Old World species previously included in Helochares (s. str.). A lectotype is designated for Peltochares conspicuus Régimbart, the type species of the genus. The taxonomic and morphological circumscription of Helochares sensu nov. is narrowed and redefined.

ResumenLa subfamilia Acidocerinae (Coleoptera: Hydrophilidae) es cosmopolita y representa uno de los linajes más diversos y taxonómicamente más desafiantes de escarabajos acuáticos detritívoros. Estudios filogenéticos recientes han incrementado considerablemente nuestro entendimiento sobre las relaciones entre acidocerinos, así como iluminaron los conceptos genéricos pobremente definidos y una clasificación ampliamente incompatible con la filogenia. Aquí se abordan estos dos desafíos proporcionando una síntesis integral y herramientas taxonómicas para Acidocerinae, incluyendo (1) un resumen de la historia y estado actual de la clasificación de Acidocerinae, (2) una revisión de la ecología y los métodos de recolección para acidocerinos, (3) el conocimiento actual de acidocerinos larvales y fósiles, (4) un manual morfológico básico sobre caracteres de importancia taxonómica y sistemática dentro del linaje, (5) una clave para los géneros de Acidocerinae del mundo, (6) diagnosis, imágenes del hábito y del edeago, mapas de distribución y resumen del conocimiento actual para cada uno de los 23 géneros existentes en la subfamilia, y (7) un catálogo taxonómico anotado y completo que incluye las distribuciones publicadas, sinónimos y referencias para todas las 541 especies de Acidocerinae descritas y reconocidas al 1 de abril de 2021. Se proponen los siguientes actos taxonómicos para alinear la clasificación con la filogenia: Colossochares gen. nov. se establece para incluir dos especies africanas descritas previamente como Helochares (s. str.); Novochares gen. nov. se establece como nuevo para acomodar 15 especies neotropicales previamente incluidas en Helochares (s. str.); los subgéneros restantes de Helochares Mulsant, Helocharimorphus Kuwert syn. nov. e Hydrobaticus MacLeay syn. nov. se sinonimizan con Helochares. Peltochares Régimbart sensu nov. es redefinido para incluir ocho especies del viejo mundo previamente incluidas en Helochares (s. str.). Se designa un lectotipo para Peltochares conspicuus Régimbart, la especie tipo del género. La circunscripción taxonómica y morfológica de Helochares sensu nov. se reduce y redefine.

New species and records of Chasmogenus Sharp, 1882 from the southwestern margin of the Guiana Shield (Coleoptera: Hydrophilidae: Acidocerinae).

The Neotropical water scavenger beetle genus Chasmogenus Sharp, 1882 is a diverse lineage with 34 described species. Here, three new species from the southwestern margin of the Guiana Shield are described using an integrative approach combining adult morphology and molecular data: Chasmogenus clinatus sp. n. (Brazil: Amazonas, Venezuela: Amazonas), C. gironae sp. n. (Venezuela: Amazonas), and C. inpa sp. n. (Brazil: Amazonas). Examination of the male genitalia is essential for confident identifications and thus unassociated females may prove extremely difficult to identify. New distributional records in Brazil for C. acuminatus Smith Short, 2020 are provided as well as habitus images of newly described species and an updated key to the species from Venezuela, Suriname, Guyana, French Guiana and northern Brazil.

Review of the Neotropical water scavenger beetle genus Tobochares Short & García, 2007 (Coleoptera, Hydrophilidae, Acidocerinae): new lineages, new species, and new records.

The water scavenger beetle genus Tobochares Short & García, 2007 currently contains ten species, including one known but formally undescribed taxon. Although Tobochares was revised in 2017, ongoing fieldwork as well as an expanded concept of the genus has led to the recognition of numerous additional species. Here a combination of morphological and molecular data is presented to review this newly found Tobochares diversity. Fifteen new species are described from South America, bringing the total number of known species to 25: Tobochares akoerio sp. nov. (Suriname), T. arawak sp. nov. (Guyana), T. anthonyae sp. nov. (Venezuela: Bolívar), T. atures sp. nov., (Venezuela: Amazonas), T. benettii sp. nov. (Brazil: Amazonas), T. canaima sp. nov. (Venezuela: Bolívar), T. communis sp. nov. (Brazil: Amapá and Roraima, Guyana, Suriname, Venezuela: Bolívar), T. fusus sp. nov. (Brazil: Amapá, French Guiana), T. goias sp. nov. (Brazil: Goiás), T. kappel sp. nov. (Suriname), T. kolokoe sp. nov. (Suriname), T. luteomargo sp. nov. (Venezuela: Bolívar), T. microps sp. nov. (Suriname), T. pemon sp. nov. (Venezuela: Bolívar), and T. romanoae sp. nov. (Brazil: Roraima). Both morphological and molecular analyses support four clades within the genus, which are here diagnosed and described as species groups. New distributional records are provided for T. kusad Kohlenberg & Short, 2017 and T. sipaliwini Short & Kadosoe, 2011, both of which are recorded from Brazil for the first time. Previously restricted to the Guiana Shield region of South America, the distributional range of the genus is now broadly expanded to include localities as far south as the central Brazilian state of Goiás. Consistent with the biology of the previously described species, almost all the new species described here are associated with seepage and wet rock habitats. Remarkably, one species, T. fusus sp. nov., was collected in both seepage habitats as well as in the rotting fruits of Clusia Linnaeus (Clusiaceae), making it one of the few known acidocerines with terrestrial habits outside of the genus Quadriops Hansen, 1999. High-resolution images of most species are included, as well as a key to species groups, species, and habitat photographs.

ResumenEl género de escarabajos acuáticos detritívoros Tobochares Short & García, 2007 actualmente contiene 10 especies, incluyendo un taxón conocido, pero no descrito. Aunque el género fue revisado en 2017, trabajo de campo en curso, así como un concepto ampliado del género han llevado al reconocimiento de numerosas especies adicionales. Aquí presentamos una combinación de datos morfológicos y moleculares para revisar esta diversidad de Tobochares recientemente encontrada. Quince especies nuevas son descritas de Suramérica, elevando el número total de especies conocidas a 25: Tobochares akoerio sp. nov. (Surinam), T. arawak sp. nov. (Guyana), T. anthonyae sp. nov. (Venezuela: Bolívar), T. atures sp. nov., (Venezuela: Amazonas), T. benettii sp. nov. (Brasil: Amazonas), T. canaima sp. nov. (Venezuela: Bolívar), T. communis sp. nov. (Brasil: Amapá y Roraima, Guyana, Surinam, Venezuela: Bolívar), T. fusus sp. nov. (Brasil: Amapá, Guyana Francesa), T. goias sp. nov. (Brasil: Goiás), T. kappel sp. nov. (Surinam), T. kolokoe sp. nov. (Surinam), T. luteomargo sp. nov. (Venezuela: Bolívar), T. microps sp. nov. (Surinam), T. pemon sp. nov. (Venezuela: Bolívar), y T. romanoae sp. nov. (Brasil: Roraima). También encontramos soporte morfológico y molecular para cuatro clados dentro del género, los cuales son aquí diagnosticados y descritos como grupos de especies. Nuevos registros de distribución son provistos para T. kusad Kohlenberg & Short, 2017 y T. sipaliwini Short & Kadosoe, 2011, ambos registrados para Brasil por primera vez. Previamente restringido a la región del Escudo Guyanés de Suramérica, el rango de distribución del género es ahora ampliamente expandido para incluir localidades tan al sur como el estado de Goiás en el centro de Brasil. Consistentes con la biología de las especies previamente conocidas, casi todas las especies descritas aquí están asociadas con hábitats higropétricos o áreas de drenaje sobre rocas. Notablemente, una especie, T. fusus sp. nov., fue colectada tanto en hábitats higropétricos como en frutos en descomposición de Clusia Linneo (Clusiaceae), constituyéndose en uno de los pocos acidocerinos conocidos con hábitos terrestres fuera del género Quadriops Hansen, 1999. Se incluyen imágenes de alta resolución de la mayoría de las especies incluidas, una clave para los grupos de especies y las especies, así como fotografías de los hábitats.

Review of the genus Chasmogenus Sharp, 1882 of northeastern South America with an emphasis on Venezuela, Suriname, and Guyana (Coleoptera, Hydrophilidae, Acidocerinae).

The water scavenger beetle genus Chasmogenus Sharp, 1882 is reviewed in northeastern South America using an integrative approach that combines adult morphology and molecular data from the gene cytochrome c oxidase I (COI). Eighteen new species are described: Chasmogenus acuminatus sp. nov. (Brazil, French Guiana, Guyana, Suriname), C. amplius sp. nov. (Venezuela), C. berbicensis sp. nov. (Guyana), C. brownsbergensis sp. nov. (Suriname), C. castaneus sp. nov. (Venezuela), C. clavijoi sp. nov. (Venezuela), C. cuspifer sp. nov. (Venezuela), C. flavomarginatus sp. nov. (Venezuela), C. gato sp. nov. (Venezuela), C. guianensis sp. nov. (Suriname, Guyana), C. ignotus sp. nov. (Brazil), C. ligulatus sp. nov. (Suriname), C. lineatus sp. nov. (Venezuela), C. pandus sp. nov. (Brazil, French Guiana, Suriname), C. schmits sp. nov. (Suriname), C. sinnamarensis sp. nov. (French Guiana), C. tafelbergensis sp. nov. (Suriname), and C. undulatus sp. nov. (Guyana). We found genetic support for an additional new species in Guyana which is currently only known from females that we refer to as Chasmogenus sp. C. We examined the holotypes of the four species previously known from the region, and found that C. occidentalis García syn. nov. and C. yukparum García syn. nov. are conspecific with C. bariorum García, 2000 and are synonymized with that species, which is here redescribed. We redescribe C. australis García and expand the range of this species to include northern Brazil, Guyana, and French Guiana. All species are aquatic, with most being associated with forested streams and forest pools. Of the 21 species, more than half (11) are only known from a single locality indicating the genus may have many more micro-endemic species yet to be discovered in the region. Characters of the male genitalia are essential for confirming the identity of some species, consequently it is not always possible to make positive identifications of unassociated female specimens based on morphology alone. Habitus images are provided as well as a revised key to the genus for northeastern South America.

Hydaticus aequalis sp. n. and a new record of H. devexus Trémouilles, 1996 from Brazil (Coleoptera, Dytiscidae, Hydaticini).

Hydaticus aequalis sp. n. is described from Brazil, where it was recently discovered in the central lowlands region of the Amazon forest. The new species differs from all other Neotropical congeners by its uniformly brown dorsal surface and the shape of medial lobe. The dorsal habitus and male genitalia are illustrated, and a distribution map is provided. The habitat, a small stream and associated forest pool, is illustrated and described. In addition, a new record of H. devexus Trémouilles, 1996, previously known from a single specimen, is reported from the highlands of northeastern Brazil, and a modified key to Neotropical species of the genus is provided.