Abstract During a study of the helminth parasites of carangid fish of the Gulf of Mexico, Protomicrocotyle mirabilis and a new member of that genus were found. The aim of the present study is to provide new morphological and sequences of 28s rDNA and CO1 mtDNA for P. mirabilis and describe the new species. Between 2005–2022, 73 specimens of Caranx spp. were purchased from local fishermen of the littoral waters of the Gulf of Mexico. Protomicrocotyle veracruzensis sp. nov. is most similar to P. mirabilis than to P. ivoriensis, the only members of the genus known from the Greater Atlantic Ocean Basin. Protomicrocotyle veracruzensis sp. nov. can be distinguished from those two species by the arrangement and number of testes. Measurement data on the haptoral armature for the new species is provided and the potential value and need for comparative data from these structures of other members of the genus is discussed. The results of the molecular analysis and the morphometric analysis of 91 characters confirmed that this new species belongs to Protomicrocotyle.

Resumo Encontraram-se durante um estudo dos helmintos parasitas de peixes carangídeos do Golfo do México, Protomicrocotyle mirabilis e um novo membro do gênero. O objetivo do presente estudo é fornecer novos dados morfológicos e sequências de 28s rDNA e CO1 mtDNA para P. mirabilis e descrever a nova espécie. Entre 2005-2022, 73 espécimes de Caranx spp. foram comprados de pescadores locais das águas litorâneas do Golfo do México. Protomicrocotyle veracruzensis sp. nov. é mais semelhante a P. mirabilis do que a P. ivoriensis, os únicos membros do género conhecidos da Grande Bacia do Oceano Atlântico. Protomicrocotyle veracruzensis sp. nov. pode ser distinguido dessas duas espécies pela disposição e número de testículos. Neste estudo são fornecidos dados de medidas da armadura haptoral para a nova espécie, discutido o valor potencial e a necessidade de dados comparativos destas estruturas de outros membros do gênero. Os resultados da análise molecular e da análise morfométrica de 91 caracteres confirmaram que essa nova espécie pertence ao gênero Protomicrocotyle.

We studied richness and distribution of amphibians and non-avian sauropsids from the 2 arid ecoregions of Hidalgo. A taxonomic list with bibliographical and field information was used, complementarity among ecoregions was analyzed and the composition of species against 5 arid regions of Mexico was compared. In addition, we discussed natural history attributes of species, their conservation status, and endemism. We report 82 species (20 amphibian and 62 non-avian sauropsids). The eco-region Central Mexican Shrub showed the greatest richness (65 species; 29 unique and 36 shared with the Central Plateau Shrub eco-region). We found 62 species distributed only in xeric shrub, 2 in deciduous tropical forest and 18 in both types of vegetation. The complementarity between ecoregions was 55 for amphibians and 32.07 for non-avian sauropsids. The greater similarity (52.4) was found with the arid zone of Querétaro. Most species are terrestrial, insectivores, and oviparous. There were more nocturnal amphibians and more diurnal non-avian sauropsids registered. Finally, 18 species are under special protection, 16 threatened and 44 are endemic to Mexico.

Se estudiaron la riqueza y la distribución de los anfibios y saurópsidos no aves de las 2 ecorregiones áridas de Hidalgo. Para ello, se realizó un listado taxonómico con información bibliográfica y de campo, se analizó la complementariedad entre ecorregiones y se comparó la composición de especies contra 5 zonas áridas de México. Además, se analizaron los atributos de historia natural de las especies, el estatus de conservación y el endemismo. Se registran 82 especies: 20 anfibios y 62 saurópsidos no aves. La ecorregión matorral central mexicano presentó la mayor riqueza con 65 especies: 29 exclusivas y 36 compartidas con la ecorregión matorral de la meseta central. Se registraron 62 especies en el matorral xerófilo, 2 en el bosque tropical caducifolio y 18 en ambos tipos de vegetación. La complementariedad entre ecorregiones fue de 55 para anfibios y 32.07 para saurópsidos no aves. La mayor similitud (52.4) se presentó con la zona árida de Querétaro. La mayoría de las especies son terrestres, insectívoras y ovíparas. Se registraron más anfibios nocturnos y más saurópsidos no aves diurnos. Finalmente, 18 especies se encuentran bajo protección especial, 16 amenazadas y 44 son endémicas de México.

ABSTRACT The distribution of Aspidoscelis gularis complex in Mexico has been difficult to model due to taxonomic problems facing its members; and because, published models exclude typical areas where taxa have been reported. The goal of this study was to update the information on the distribution of A. gularis complex and suggest a model applicable to species groups considered "complex", as well as to any taxonomic level. The generated information allowed developing a distribution model through Mahalanobis-typicality algorithm in IDRISI Taiga, validated using the area under the curve (AUC), with value of 0.932. The modeled distribution spanned in the states belonging to the Mexican Plateau. It was found that the taxa of the complex were associated with the Mexican Plateau's vegetation, classified as Chihuahuan desert. The vegetation was composed mainly by xeric scrub and grasslands, suggesting a factor that limits their distribution in northern and central Mexico, as it happens similar to other groups of reptiles.

RESUMEN La distribución del complejo Aspidoscelis gularis en México ha sido difícil de modelar debido a los problemas taxonómicos que enfrentan sus integrantes y a que los modelos publicados excluyen zonas típicas donde los taxones han sido reportados. El objetivo de este trabajo fue actualizar la información sobre la distribución del complejo A. gularis y proponer un modelo aplicable a grupos de especies considerados "complejos", así como a cualquier nivel taxonómico. La información generada permitió desarrollar un modelo de distribución con el algoritmo Tipicidad de Mahalanobis en IDRISI Taiga, que se validó con el área bajo la curva (AUC), con un valor de 0.932. La distribución modelada abarcó estados pertenecientes al Altiplano Mexicano. Se encontró que los taxones del complejo están asociados con la vegetación característica del Altiplano Mexicano, clasificada como desierto Chihuahuense, compuesta principalmente por matorrales xerófilos y pastizales, lo que sugiere un factor que limita su distribución en el norte hasta el centro de México, similar con otros grupos de reptiles.