The philometrid nematodePhilometroides acreanensis n. sp. from the stomach wall of the catfishPimelodus blochiiin north-western Brazil

Abstract

A new nematode species, Philometroides acreanensis n. sp. (Philometridae), is described from female specimens recovered from the stomach wall of the freshwater catfish Pimelodus blochii Valenciennes (Pimelodidae) collected in the Acre River (Amazon River basin), Acre State, Brazil. Based on examination by light and scanning electron microscopy, the new species differs from the two other South American congeneric species mainly in the body length of the gravid female (240-280 mm), the length of the oesophagus (1.25 mm in holotype) representing 0.5% of the entire body length, the range of cuticular embossment, as well as the location in the host (stomach), order of the fish host (Siluriformes) and the geographical distribution (Amazon River drainage system). This is the third known species of Philometroides Yamaguti, 1935 reported from South America. A key to species of Philometroides occurring in the fish of America is provided.

MORPHOLOGICAL AND GENETIC CHARACTERIZATION OF NEMATODES OF THE OPOSSUM Didelphis albiventris AND THE ARMADILLO Dasypus novemcinctus FROM SERRA DA CAPIVARA NATIONAL PARK

“…Nematode specimens were washed in 0.1 M cacodylate buffer pH 7.2, post-fixed in 1% OsO 4 and 0.8% potassium ferrocyanide for 1 h, dehydrated in a graded series of ethanol solutions (30-100%) for 1 h for each step, critical-point dried in CO 2 and sputter coated with gold (Cavalcante et al 2018). The specimens were examined using a Jeol JSM 6390 SEM.…”

Community structure of metazoan parasites from Pimelodus blochii in two rivers of the Western Brazilian Amazon: same seasonal traits, but different anthropogenic impacts

“…Currently, there are no studies regarding the ecology of parasite communities from the catfish Pimelodus blochii Valenciennes (Siluriformes: Pimelodidae); studies have been focused solely on taxonomy of parasites and species catalogue (Gil de Pertierra 2004; Luque and Tavares 2007;Kohn et al 2007;Luque et al 2011;Mendoza-Palmero and Scholz 2011;Orélis-Ribeiro and Bullard 2015;Cavalcante et al 2016Cavalcante et al , 2018. Pimelodus blochii has economic importance and is widely distributed in South America (Lundberg and Littmann 2003;Froese and Pauly 2018); therefore, the community dynamics of parasites from this fish should be better understood.…”

First description of the male of Philometroides acreanensis and phylogenetic assessment of Philometridae (Nematoda: Dracunculoidea) suggest instability of some taxa

“…Recently, Philometroides acreanensis was described based on female specimens parasitizing the catfish Pimelodus blochii from River Acre, State of Acre, Brazil [6]. The description of new species of philometrids based solely on gravid females is common, because males are very small, difficult to find and may occupy different sites of infection than those of females [1].…”