Jorge Falcón-Ordaz

Helminth Parasites of Pseudacris hypochondriaca (Anura: Hylidae) from Baja California, Mexico, with the Description of Two New Species of Nematodes

Abstract:  The helminth parasite fauna of the hylid frog Pseudacris hypochondriaca in several localities along the Baja California Peninsula in northwestern Mexico is presented. The helminth fauna consists of 4 species of nematodes (Oswaldocruzia pipiens, a larval form of an Ascaridid, 2 new species belonging to the genera Rhabdias and Cosmocercoides), and 1 species of digenean (Gorgoderina sp.). The new species of Rhabdias represents the 88th species assigned to the genus and the third species described from Mexican anurans. Also, the species of Cosmocercoides represents the 20th species assigned to the genus and the first representative of this genus described from Mexico.

A NEW DICROCOELIID (DIGENEA: DICROCOELIINAE) PARASITE OF RODENTS FROM TLAXCALA, MEXICO

Caballerolecythus ibunami n. gen., n. sp. is described from the intestine of 2 species of rodents (Liomys irroratus [Gray, 1868] and Peromyscus difficilis [Allen, 1891]) from Piñonal, El Carmen Tequexquitla, Tlaxcala state, Mexico. These specimens represent a new genus and a new species of Dicrocoeliinae by possession of an extremely short ceca (ending at equatorial level of ovary); vitelline follicles that begin posterior to these structures, without overlapping; and a body that is long and slender (length/width ratio 1:17–21). To the best of our knowledge, this combination of characters has not been reported in other genera of this subfamily (Athesmia Looss, 1899; Unilaterilecithum Oshmarin in Skrjabin and Evranova, 1952; and Pseudathesmia Travassos, 1942).

A New Species of Heteromyoxyuris (Nematoda: Oxyuridae), Parasite of Perognathus flavus (Rodentia: Heteromyidae) From Mexico

Heteromyoxyuris otomii n. sp., which inhabits the intestinal caecum of Perognathus flavus (Heteromyidae), in Zaragoza, Hidalgo, Mexico, is described. This new species differs from the 2 other congeneric species in the morphology and length of lateral alae in males. Heteromyoxyuris deserti has simple lateral alae located at both sides of the body, whereas in the new species, these structures are double at both sides; in contrast, lateral alae of Heteromyoxyuris longejector begin at the posterior half of the body, whereas they arise in the first third in the new species. Heteromyoxyuris longejector was found in 2 new host species, i.e., Perognathus amplus and Chaetodipus hispidus. This record represents the first record for the species in Mexico, increasing its geographic distribution.

A NEW SPECIES OF VEXILLATA (NEMATODA: TRICHOSTRONGYLINA: ORNITHOSTRONGYLIDAE) PARASITE OF HETEROMYS DESMARESTIANUS (RODENTIA: HETEROMYIDAE) FROM COSTA RICA

In July 1999, 2 heteromyid rodents Heteromys desmarestianus Gray, 1868, were collected from the Área de Conservación Guanacaste, Costa Rica, and examined for parasites. Individuals of a new species of Vexillata (Travassos, 1937) Durette-Desset, 1970, were found from the intestine of hosts. Vexillata brooksi n. sp. differs from all other congeners by the presence of spicules divided at the tip instead of simple spicules. The new species closely resembles Vexillata legallae Denke, 1977, and Vexillata convoluta (Caballero and Cerecero, 1943); however, it can be distinguished from both species by possessing a smaller number of cuticular ridges at the posterior part of the body in males (9 vs. 11 and 12, respectively) and by the absence of a carene at this level.

VEXILLATA LIOMYOS N. SP. (NEMATA: ORNITHOSTRONGYLIDAE) FROM LIOMYS PICTUS (RODENTIA: HETEROMYIDAE) FROM MEXICO, WITH COMMENTS ON THE SYNLOPHE OF VEXILLATA ARMANDAE

Individuals of a new species of Vexillata were collected from the small intestines of Liomys pictus from the Estación de Biología Chamela, in Jalisco State, Mexico. The new species shows an array of characters that allow us to recognize it as a member of Vexillata; however, it can be distinguished from other species of the genus in that males possess an asymmetrical caudal bursa, females possess a characteristic cuticular inflation at the level of the ovijector, and both sexes possess a synlophe with 9 ridges at the midbody. Additional detail of the synlophe of Vexillata armandae Gardner et al., 1994 from Chaetodipus hispidus in New Mexico shows that both sexes have 12 cuticular ridges just posterior to the cephalic inflation, and in the posterior region of the body, females have 9 ridges of equal size while males possess 11 equal-sized ridges. In both sexes, the carene disappears at the posterior end of the body.

PHYLOGENETIC RELATIONSHIPS AMONG SPECIES OF STILESTRONGYLUS FREITAS, LENT AND ALMEIDA, 1937 (TRICHOSTRONGYLOIDEA: HELIGMONELLIDAE: NIPPOSTRONGYLINAE), PARASITES OF MYOMORPH RODENTS (RODENTIA: MURIDAE) IN THE NEOTROPICS

The phylogenetic relationships of 14 species of Stilestrongylus were analyzed using the comparative morphology of 21 characters. We obtained 2 shortest trees of 50 steps, with a consistency index of 0.540 and 25 apomorphic character states. Ingroup monophyly was supported on these trees by 2 and 3 synapomorphies, respectively, and the ingroup was defined by the following characters: greater number of ventral ridges relative to the number of ridges dorsally, asymmetric bursa, and externodorsal rays differing in size. Sister-group relationships among Stilestrongylus and the other genera designated as outgroups are relatively consistent with those postulated by Durette-Dessets in a classification of the Nippostrongylinae. The ancestor of the species groups comprising Hassalstrongylus, Guerrerostrongylus, and Stilestrongylus originated and diversified in murids in the Neotropical region. Species of Hassalstrongylus occur in rodents between southeastern North America and the eastern part of South America (Brazil and Argentina), whereas species of Guerrerostrongylus and Stilestrongylus diversified exclusively in rodents in the Neotropics.

Lagochilascaris minor (Nematoda: Ascarididae) from a Wild Cougar ( Puma concolor ) in Mexico.

Abstract We document parasitation of a wild cougar (Puma concolor) by the nematode Lagochilascaris minor in Hidalgo State, Mexico. This finding contributes to our understanding of the epidemiology of this zoonotic agent in Mexico.

A NEW SPECIES OF SCIURODENDRIUM (NEMATODA: HELIGMONELLIDAE) IN SCIURUS AUREOGASTER (RODENTIA: SCIURIDAE) FROM MORELOS, MEXICO

Sciurodendrium bravohollisae n. sp. (Heligmonellidae) is described as an intestinal parasite of 2 squirrels, Sciurus aureogaster Cuvier, 1829, collected from Los Robles, Municipio de Tlalnepantla, Morelos State, Mexico. The new species differs from all other congeners in possessing a very well-developed and sacciform genital cone. This is the seventh species described for the genus and the first one recorded in Mexico.

A NEW SPECIES OF VEXILLATA (NEMATODA: ORNITHOSTRONGYLIDAE) IN ATTWATER'S POCKET GOPHER FROM TEXAS

Vexillata geomyos n. sp. is described as a parasite of Attwaters pocket gopher, Geomys attwateri (Geomyidae), from Welder Wildlife Refuge, Texas. The new species possesses 12 cuticular ridges; based on this character, it can be distinguished from 7 of the 13 species in the genus. From the 6 remaining species, V. geomyos can be differentiated because the dorsal ray in 3 of them (V. armandae, V. dessetae, and V. vexillata) has 2 short branches arising from main trunk, whereas dorsal ray of the new species lacks these branches. In addition, V. geomyos can be distinguished from V. brooksi because its spicules are divided at the tip (whereas in the new species, spicules are whole). The new species differs from V. legallae and V. convoluta in the number and arrangement of cuticular ridges at the posterior region of the body.

TADARIDANEMA DELICATUS (SCHWARTZ, 1927) N. GEN., N. COMB. (TRICHOSTRONGYLINA: MOLINEIDAE) PARASITE OF MOLOSSIDAE BATS

On the basis of the revision of the type material of Anoplostrongylus delicatus Schwartz, 1927, and new specimens collected from Tadarida brasiliensis mexicana (Saussure, 1860) in 4 arid localities from Mexico, we describe a new genus (Tadaridanema n. gen.), to which A. delicatus is transferred (as Tadaridanema delicatus (Schwartz, 1927) n. gen., n. comb.). This new genus differs from all other genera included in Anoplostrongylinae by having ray 2 larger than ray 3. In addition, T. delicatus can be differentiated from the type species of Anoplostrongylus (Anoplostrongylus paradoxus (Travassos, 1918)) because it possess vestibular branches equal in length, cephalic inflation divided into 2 regions, and synlophe with many small ridges at the midbody level, whereas in T. delicatus, vestibular branches are equal in size, cephalic inflation is simple in structure, and the synlophe has only 2 well-developed dorsal cuticular ridges.