Variation in patterns of fish assemblage and their environmental correlates in a tropical river basin from the Gulf of Mexico slope

Understanding patterns of freshwater fish assemblage structure is key to protect them from ongoing human-induced threats to aquatic biodiversity. Yet, studies on associations between fish assemblages and habitat are lacking from many areas of high diversity in Middle America. We assessed fish assemblage structure and environmental associations from a portion of the Lacantún River sub-basin (Usumacinta River, Chiapas, Mexico). Based on environmental data and 17,462 individuals (56 species, 46 genera, and 22 families) captured from 13 sites sampled between 2017­2019, we found that stream order, distance to the Usumacinta, forest cover, temperature, and dissolved oxygen are key to explaining assemblage composition. Four clusters were found via multivariate regression tree analysis, with stream order and dissolved oxygen as defining variables. Our findings suggest that fish communities remain spatially structured even at small scales, in association to environmental gradients among habitats.(AU)

Comprender los patrones de estructuración en los ensamblajes de peces dulceacuícolas es una clave para protegerlos de las amenazas humanas a la biodiversidad acuática. No obstante, los estudios sobre asociaciones entre ensamblajes de peces y su hábitat son aún escasos en muchas áreas de alta diversidad de América Media. Evaluamos las asociaciones entre la estructura de los ensamblajes de peces y el ambiente de una porción de la subcuenca del Río Lacantún (cuenca del Río Usumacinta, Chiapas, México). Con base en datos ambientales y un total de 17,462 individuos (56 especies, 46 géneros, y 22 familias) capturados de 13 sitios muestreados entre 2017­2019, encontramos que el orden del cauce, distancia al Usumacinta, cobertura vegetal, temperatura y oxígeno disuelto son clave para explicar la composición de los ensamblajes. Cuatro grupos se detectaron utilizando un árbol de regresión multivariada, definidos por el orden del cauce y el oxígeno disuelto como variables definitorias. Nuestros hallazgos sugieren que las comunidades de peces retienen su estructura espacial aún a pequeñas escalas, en asociación a gradientes ambientales entre hábitats.(AU)

Two new species and taxonomical and geographical notes on Aegomorphus Haldeman (Coleoptera, Cerambycidae, Lamiinae)

Acanthoderes crocostigma Bates, 1880 is transferred to Acakyra Martins & Galileo, 1996. Acanthoderes umbrata Bates, 1885 is synonymized with Acanthoderes purulensis Bates, 1885. Variation of the elytral pubescent pattern in Aegomorphus longitarsis (Bates, 1880) is reported, and the species is recorded for the first time from Colombia (Boyacá) and Brazil (Amazonas). The variation of the elytral pubescent pattern in Aegomorphus doctus (Bates, 1880) is reported, and the species is recorded for the first time from the Mexican state of Jalisco. We comment on the type-locality of Aegomorphus borrei (Dugès, 1885). Two new species are described from Mexico (Jalisco): Aegomorphus cunninghami and A. nogueirai.(AU)

The first record of the genus Plega Navás, 1928 (Neuroptera: Rhachiberothidae: Symphrasinae) as a parasitoid of the sawfly genus Monoctenus Dahlbom, 1835 (Hymenoptera: Symphyta: Diprionidae)

The genus Plega Navás, 1928, belongs to the subfamily Symphrasinae, a group recently transferred from Mantispidae to Rhachiberothidae. This genus is herein reported as parasitoid of the symphytan family Diprionidae for the first time, becoming the first record of association between this neuropteran subfamily and non-aculeate Hymenoptera. This new association was discovered in "Ixcateopan de Cuauhtémoc", in the Mexican state of Guerrero, where Plega spinosa Ardila et al., 2019 was found associated with immatures of the sawfly Monoctenus cuauhtemoci De Lira, 2021, a pest in forests of Juniperus flaccida Schlechtendal (white cedar). The neuropteran was found to be the most abundant parasitoid of this symphytan, becoming a potential candidate for biological control of phytophagous sawflies in juniper forests, an economically important plant species for the wood industry in the region. Considering the behavior and morphological aspects of the primary larvae and the behavior of the adults of Plega, three possible scenarios in which the primary larvae of P. spinosa board the larvae of Monoctenus to complete its life cycle are outlined. This finding reinforces the hypothesis of a generalist ectoparasitoid lifeway of the larvae of the genus Plega on larvae and pupae of holometabolous insects.(AU)

First record and a new species of Euphrosynoplax (Crustacea: Pseudorhombilidae) from the southwestern Atlantic

Abstract A new species of deep-water brachyuran crab, Euphrosynoplax dincao, from southeastern Brazil is described and illustrated. The genus Euphrosynoplax currently consists of two species, E. clausaGuinot, 1969, and E. campechiensisVázquez-Bader & Gracia, 1991, both only known from the Gulf of Mexico. The new species can be easily separated from its northern counterparts by a suite of carapace and appendage characters. Euphrosynoplax campechiensis is recorded for the first time from the Caribbenan Sea (Guadeloupe and between Saint Kitts and Nevis).

Contribution to the knowledge of the Neotropical Anteoninae (Hymenoptera, Dryinidae), with the descriptions of two new species and new records

Abstract Two new species of Anteoninae (Hymenoptera, Chrysidoidea, Dryinidae) are described: Deinodryinus brasiliensis sp. nov., from Brazil (Bahia, Minas Gerais and Paraná) and D. mexicanus sp. nov., from Mexico (Chiapas). Comments on Lonchodryinus tricolorKieffer, 1905 are presented and new geographic records are provided for the Brazilian states of Minas Gerais and Paraná. The key to the females of the Neotropical Deinodryinus is updated, and illustrations and distributional maps are provided for the species studied here.

First record and a new species of Euphrosynoplax (Crustacea: Pseudorhombilidae) from the southwestern Atlantic

Abstract A new species of deep-water brachyuran crab, Euphrosynoplax dincao, from southeastern Brazil is described and illustrated. The genus Euphrosynoplax currently consists of two species, E. clausaGuinot, 1969, and E. campechiensisVázquez-Bader & Gracia, 1991, both only known from the Gulf of Mexico. The new species can be easily separated from its northern counterparts by a suite of carapace and appendage characters. Euphrosynoplax campechiensis is recorded for the first time from the Caribbenan Sea (Guadeloupe and between Saint Kitts and Nevis).

Contribution to the knowledge of the Neotropical Anteoninae (Hymenoptera, Dryinidae), with the descriptions of two new species and new records

Abstract Two new species of Anteoninae (Hymenoptera, Chrysidoidea, Dryinidae) are described: Deinodryinus brasiliensis sp. nov., from Brazil (Bahia, Minas Gerais and Paraná) and D. mexicanus sp. nov., from Mexico (Chiapas). Comments on Lonchodryinus tricolorKieffer, 1905 are presented and new geographic records are provided for the Brazilian states of Minas Gerais and Paraná. The key to the females of the Neotropical Deinodryinus is updated, and illustrations and distributional maps are provided for the species studied here.

Contribution to the knowledge of the Neotropical Anteoninae (Hymenoptera, Dryinidae), with the descriptions of two new species and new records

Two new species of Anteoninae (Hymenoptera, Chrysidoidea, Dryinidae) are described: Deinodryinus brasiliensissp. nov., from Brazil (Bahia, Minas Gerais and Paraná) and D. mexicanussp. nov., from Mexico (Chiapas). Comments on Lonchodryinus tricolor Kieffer, 1905 are presented and new geographic records are provided for the Brazilian states of Minas Gerais and Paraná. The key to the females of the Neotropical Deinodryinus is updated, and illustrations and distributional maps are provided for the species studied here.(AU)

First record and a new species of Euphrosynoplax(Crustacea: Pseudorhombilidae) from the southwestern Atlantic

A new species of deep-water brachyuran crab, Euphrosynoplax dincao, from southeastern Brazil is described and illustrated. The genus Euphrosynoplax currently consists of two species, E. clausa Guinot, 1969, and E. campechiensis Vázquez-Bader & Gracia, 1991, both only known from the Gulf of Mexico. The new species can be easily separated from its northern counterparts by a suite of carapace and appendage characters. Euphrosynoplax campechiensis is recorded for the first time from the Caribbenan Sea (Guadeloupe and between Saint Kitts and Nevis).(AU)

Description of a new species of Engraulicola George 1960 (Monogenea: Gastrocotylidae) parasitizing gills of Chloroscombrus chrysurus (Carangidae) from Veracruz, southern Gulf of Mexico / Descrição de uma nova espécie de Engraulicola George 1960 (Monogenea: Gastrocotylidae) parasito de brânquias de Chloroscombrus chrysurus (Carangidae) de Veracruz, Sul do Golfo do México

Engraulicola lamothei n. sp. (Monogenea: Gastrocotylidae) is described from the gills of Chloroscombrus chrysurus (Teleostei: Carangidae) from Veracruz, southern Gulf of Mexico. This monogenean is 1110-1670 (1328) µm long and 260-550 (363) µm wide. The haptor is asymmetrical, the long side has several clamps (35-42), and the short side has a single clamp; the posterior end has a small lappet armed with two dissimilar pairs of hooks. Male and female genital pores open near the anterior body end; the male genital pore is ventral, armed with a corona of 12 spines; the female pore is dorsal and unarmed. The new species differs from Engraulicola forcipopenis George, 1960 and from Engraulicola micropharyngella Unnithan, 1967 by lacking a pair of pointed forceps-like spines at the end of the penis amid the corona spines, and from Engraulicola thrissocles Tripathi, 1959 by the number of clamps on both sides, the number the hook pairs on the terminal lappet and the testis number. This is the first record of the genus Engaulicola George, 1960 on the Atlantic West Coast.(AU)

Engraulicola lamothei n. sp. (Monogenea: Gastrocotylidae) é descrito a partir das brânquias de Chloroscombrus chrysurus (Teleostei: Carangidae) de Veracruz, Sul do Golfo do México. Este monogêneo tem 1110-1670 (1328) µm de comprimento e 260-550 (363) µm de largura. O haptor é assimétrico, o lado longo tem vários grampos (35-42), e o lado curto tem um único grampo, e a extremidade posterior tem um pequeno lappet armado com dois pares de ganchos diferentes. Os poros genitais masculino e feminino são abertos perto da extremidade anterior do corpo; o poro genital masculino é ventral, armado com uma coroa de 12 espinhos; o poro feminino é dorsal e desarmado. A nova espécie difere de Engraulicola forcipopenis George, 1960 e de Engraulicola micropharyngella Unnithan, 1967, pela ausência de um par de fórceps pontiagudos como espinhos localizados na extremidade do pênis, em meio aos espinhos da coroa; e de Engraulicola thrissocles Tripathi, 1959, pelo número de pinças em ambos os lados, pelo número de pares de ganchos no lappet terminal, e pelo número de testículos. Este é o primeiro registro do gênero Engaulicola George, 1960 para a costa oeste do Atlântico.(AU)

Temporal and spatial segregation of top predators (Felidae) in a Mexican tropical Biosphere Reserve

ABSTRACT Jaguars, Panthera onca (Linnaeus, 1758), and pumas, Puma concolor (Linnaeus, 1771) are the largest felids in the neotropics. Both can overlap in niche axes (time, space and prey), and are therefore potentially competing species. Segregation mechanisms presented by a low overlap in one of these axes of niche can facilitate the coexistence. Our aim was to analyze jaguar and puma temporal and spatial overlap for understanding their segregation mechanisms. Between 2015 and 2017, twenty-six camera trap stations were located in five habitat types of El Cielo Biosphere Reserve (ECBR) in northeastern Mexico. Temporal activity was analyzed using circular statistics and time overlap analysis. Spatial overlap was calculated with the Pianka index and a selectivity habitat analysis. Our results showed that jaguars and pumas were nocturnal and that the temporal overlap was high (4 = 0.77). We found an intermediate spatial overlap (Pianka index = 0.61). Jaguars were more selective and preferred the deciduous forest. In comparison, pumas preferred oak-pine forest, but also used oak and deciduous forest. Our results indicate that spatial segregation best explains the coexistence of jaguars and pumas in our study area, probably due to both habitat diversity in the reserve and the generalist habits of the puma.

Temporal and spatial segregation of top predators (Felidae) in a Mexican tropical Biosphere Reserve

Jaguars, Panthera onca (Linnaeus, 1758), and pumas, Puma concolor (Linnaeus, 1771) are the largest felids in the neotropics. Both can overlap in niche axes (time, space and prey), and are therefore potentially competing species. Segregation mechanisms presented by a low overlap in one of these axes of niche can facilitate the coexistence. Our aim was to analyze jaguar and puma temporal and spatial overlap for understanding their segregation mechanisms. Between 2015 and 2017, twenty-six camera trap stations were located in five habitat types of El Cielo Biosphere Reserve (ECBR) in northeastern Mexico. Temporal activity was analyzed using circular statistics and time overlap analysis. Spatial overlap was calculated with the Pianka index and a selectivity habitat analysis. Our results showed that jaguars and pumas were nocturnal and that the temporal overlap was high (∆4 = 0.77). We found an intermediate spatial overlap (Pianka index = 0.61). Jaguars were more selective and preferred the deciduous forest. In comparison, pumas preferred oak-pine forest, but also used oak and deciduous forest. Our results indicate that spatial segregation best explains the coexistence of jaguars and pumas in our study area, probably due to both habitat diversity in the reserve and the generalist habits of the puma.(AU)

Temporal and spatial segregation of top predators (Felidae) in a Mexican tropical Biosphere Reserve

Jaguars, Panthera onca (Linnaeus, 1758), and pumas, Puma concolor (Linnaeus, 1771) are the largest felids in the neotropics. Both can overlap in niche axes (time, space and prey), and are therefore potentially competing species. Segregation mechanisms presented by a low overlap in one of these axes of niche can facilitate the coexistence. Our aim was to analyze jaguar and puma temporal and spatial overlap for understanding their segregation mechanisms. Between 2015 and 2017, twenty-six camera trap stations were located in five habitat types of El Cielo Biosphere Reserve (ECBR) in northeastern Mexico. Temporal activity was analyzed using circular statistics and time overlap analysis. Spatial overlap was calculated with the Pianka index and a selectivity habitat analysis. Our results showed that jaguars and pumas were nocturnal and that the temporal overlap was high (∆4 = 0.77). We found an intermediate spatial overlap (Pianka index = 0.61). Jaguars were more selective and preferred the deciduous forest. In comparison, pumas preferred oak-pine forest, but also used oak and deciduous forest. Our results indicate that spatial segregation best explains the coexistence of jaguars and pumas in our study area, probably due to both habitat diversity in the reserve and the generalist habits of the puma.(AU)

A retrospective study of neoplasms in ornamental and pet birds diagnosed at the Hospital de Aves of the Universidad Nacional Autónoma de México (2007-2014)

A retrospective study including a total of 44 ornamental and pet birds with neoplasms diagnosed at the Hospital de Aves, Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México from January 2007 to April 2014 was conducted. Most of affected birds were Psittaciformes (n=26, 59%) including budgerigars (Melopsittacus undulatus) (n=12/26, 46.15%) and amazon parrots (Amazona spp.) (n=7/26, 26.92%), and followed by Passeriformes and Anseriformes (n=7/44, 15.90%, each) and Galliformes (n=4/44, 9.09%). The youngest studied bird was a 6.5-week-old lovebird (Agapornis sp.) with a papilloma, and the oldest bird was a 37-year-old yellow-naped parrot (Amazona auropalliata) with a hemangiosarcoma. Most of the affected birds were adults (n=23, 52.27%). The gender was determined for 17 birds (38.63%), of which eight (47.05%) were females and nine (52.94%) males. There were 45 reported neoplasms,as one salmon-crested cockatoo (Cacatua moluccensis) had two neoplasms. The two most frequent neoplasms were fibrosarcomas (n=9/45, 20%) and hemangiosarcomas (n=5/45, 11.11%). The largest number of neoplasms was found in the integumentary system (n=18/45, 40%), followed by the reproductive system (n=10/45, 22.22%). Of the 16 types of neoplasms, seven (43.75%) were malignant, six (37.5%) were benign, and three (18.75%) were potentially malignant. This study showed similarities with retrospective previously reported studies and contributes to the knowledge of the neoplastic diseases that occur in ornamental and pet birds in Mexico.(AU)

A retrospective study of neoplasms in ornamental and pet birds diagnosed at the Hospital de Aves of the Universidad Nacional Autónoma de México (2007-2014)

A retrospective study including a total of 44 ornamental and pet birds with neoplasms diagnosed at the Hospital de Aves, Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México from January 2007 to April 2014 was conducted. Most of affected birds were Psittaciformes (n=26, 59%) including budgerigars (Melopsittacus undulatus) (n=12/26, 46.15%) and amazon parrots (Amazona spp.) (n=7/26, 26.92%), and followed by Passeriformes and Anseriformes (n=7/44, 15.90%, each) and Galliformes (n=4/44, 9.09%). The youngest studied bird was a 6.5-week-old lovebird (Agapornis sp.) with a papilloma, and the oldest bird was a 37-year-old yellow-naped parrot (Amazona auropalliata) with a hemangiosarcoma. Most of the affected birds were adults (n=23, 52.27%). The gender was determined for 17 birds (38.63%), of which eight (47.05%) were females and nine (52.94%) males. There were 45 reported neoplasms,as one salmon-crested cockatoo (Cacatua moluccensis) had two neoplasms. The two most frequent neoplasms were fibrosarcomas (n=9/45, 20%) and hemangiosarcomas (n=5/45, 11.11%). The largest number of neoplasms was found in the integumentary system (n=18/45, 40%), followed by the reproductive system (n=10/45, 22.22%). Of the 16 types of neoplasms, seven (43.75%) were malignant, six (37.5%) were benign, and three (18.75%) were potentially malignant. This study showed similarities with retrospective previously reported studies and contributes to the knowledge of the neoplastic diseases that occur in ornamental and pet birds in Mexico.

Species or population? Systematic status of Vieja coatlicue (Teleostei: Cichlidae)

Pacific and Atlantic-slope rivers of the Isthmus of Tehuantepec in Mexico contain two cichlid species of the genus Vieja relevant to the current study, V. zonata and V. coatlicue, respectively. The Atlantic-slope species was initially considered a population of uncertain taxonomic status and recently described as a distinct species based on three putatively diagnostic morphological characters. The objective of this study was to combine new and existing genetic data, along with reanalysis of morphological characters, to test the distinctiveness of V. coatlicue. Little genetic variability and no geographic structuring were recovered. Additionally, putatively diagnostic morphological character states were present across both species, failing to separate the forms. The synthesis of molecular and morphological data supports the recognition of V. coatlicue as a junior synonym of V. zonata.(AU)

Dos especies del género Vieja se encuentran distribuidas a lo largo Istmo de Tehuantepec en México; V. zonata se distribuye en los ríos de la vertiente del Pacífico y V. coatlicue en los ríos de la vertiente del Atlántico. La especie que se distribuye en la vertiente del Atlántico era considerada como una población de estado taxonómico incierto, pero recientemente fue descrita como nueva especie en base a tres caracteres morfológicos diagnósticos. El objetivo de este estudio fue utilizar datos moleculares nuevos con datos moleculares previamente publicados en combinación con una reanálisis de los caracteres morfológicos para testear la validez taxonómica de la especie V. coatlicue. Nuestros análisis moleculares no recobran estructura geográfica y además muestran baja variabilidad genética. Además, los tres caracteres morfológicos diagnósticos se encontraron presentes en individuos de ambas especies, nuestro trabajo sugiere que estos caracteres morfológicos diagnósticos no proven información que permita separar a las formas que se distribuyen en la vertiente del Pacífico y la vertiente del Atlántico. Nuestra síntesis de datos moleculares y morfológicos provee evidencia para reconocer a V. coatlicue como una sinónima mas reciente de V. zonata.(AU)

Species or population? Systematic status of Vieja coatlicue (Teleostei: Cichlidae)

Pacific and Atlantic-slope rivers of the Isthmus of Tehuantepec in Mexico contain two cichlid species of the genus Vieja relevant to the current study, V. zonata and V. coatlicue, respectively. The Atlantic-slope species was initially considered a population of uncertain taxonomic status and recently described as a distinct species based on three putatively diagnostic morphological characters. The objective of this study was to combine new and existing genetic data, along with reanalysis of morphological characters, to test the distinctiveness of V. coatlicue. Little genetic variability and no geographic structuring were recovered. Additionally, putatively diagnostic morphological character states were present across both species, failing to separate the forms. The synthesis of molecular and morphological data supports the recognition of V. coatlicue as a junior synonym of V. zonata.(AU)

Dos especies del género Vieja se encuentran distribuidas a lo largo Istmo de Tehuantepec en México; V. zonata se distribuye en los ríos de la vertiente del Pacífico y V. coatlicue en los ríos de la vertiente del Atlántico. La especie que se distribuye en la vertiente del Atlántico era considerada como una población de estado taxonómico incierto, pero recientemente fue descrita como nueva especie en base a tres caracteres morfológicos diagnósticos. El objetivo de este estudio fue utilizar datos moleculares nuevos con datos moleculares previamente publicados en combinación con una reanálisis de los caracteres morfológicos para testear la validez taxonómica de la especie V. coatlicue. Nuestros análisis moleculares no recobran estructura geográfica y además muestran baja variabilidad genética. Además, los tres caracteres morfológicos diagnósticos se encontraron presentes en individuos de ambas especies, nuestro trabajo sugiere que estos caracteres morfológicos diagnósticos no proven información que permita separar a las formas que se distribuyen en la vertiente del Pacífico y la vertiente del Atlántico. Nuestra síntesis de datos moleculares y morfológicos provee evidencia para reconocer a V. coatlicue como una sinónima mas reciente de V. zonata.(AU)

Parasites in feces of the endemic rattlesnake, Crotalus triseriatus (Serpentes: Viperidae), from Mexican highlands

There are few studies about parasitic infections in Crotalus triseriatus (Wagler, 1830), an endemic rattlesnake from the highlands of central Mexico. This species occupies several habitats, from conserved forested regions to heavily impacted landscapes. To increase the parasitological knowledge of this reptile species without impacting populations, we obtained fecal samples of 16 rattlesnakes between 2012 and 2014 from Toluca Valley, Mexico. By using flotation technique, we found oocysts of Eimeria sp. and eggs of Capillariidae sp. The most frequent parasite was Eimeria sp. (62.5%). This study provides the first records of occurrence of parasites in reptilian feces from Mexico. Our results may be important for wildlife conservation purposes, for example, they could indicate of the population health of this species during processes of translocation.

Parasites in feces of the endemic rattlesnake, Crotalus triseriatus (Serpentes: Viperidae), from Mexican highlands

There are few studies about parasitic infections in Crotalus triseriatus (Wagler, 1830), an endemic rattlesnake from the highlands of central Mexico. This species occupies several habitats, from conserved forested regions to heavily impacted landscapes. To increase the parasitological knowledge of this reptile species without impacting populations, we obtained fecal samples of 16 rattlesnakes between 2012 and 2014 from Toluca Valley, Mexico. By using flotation technique, we found oocysts of Eimeria sp. and eggs of Capillariidae sp. The most frequent parasite was Eimeria sp. (62.5%). This study provides the first records of occurrence of parasites in reptilian feces from Mexico. Our results may be important for wildlife conservation purposes, for example, they could indicate of the population health of this species during processes of translocation.(AU)

Complementary description of Neanopidium mexicanum (Coleoptera: Tenebrionidae: Anopidiina) / Descrição complementar de Neanopidium mexicanum (Coleoptera: Tenebrionidae: Anopidiina)

A complementary description for Neanopidium mexicanum Dajoz, 1975, type species of the genus, is provided based on specimens from the type locality Valle Nacional (Oaxaca, Mexico), including description and illustrations of male and female abdominal terminalia, which is provided for the first time to a Neanopidium species.(AU)