A cyanobacterium containing phycobiliproteins with far-red acclimation was isolated from Pozas Rojas, Cuatro Ciénegas, México. It was named Leptolyngbya CCM 4 after phylogenetic analysis and a description of its morphological characteristics. Leptolyngbya was grown in far-red light. Sucrose-gradient analysis of the pigments revealed two different colored bands of phycobiliproteins. A band at 60% sucrose was a phycocyanin containing phycobilisome; at 35% sucrose, a new type of phycobiliprotein absorbed at 710 nm. SDS-PAGE revealed the presence of two types of core-membrane linkers. Analysis of the hydrophobic pigments extracted from the thylakoid membranes revealed Chl a, d, and f. The ratio of Chl f/a was reversibly changed from 1:12-16 under far-red light to an undetectable concentration of Chl f under white light. Cuatro Ciénegas, a place surrounded by the desert, is a new ecosystem where a cyanobacterium, which grows in farred light, was discovered., C. Gómez-Lojero, L. E. Leyva-Castillo, P. Herrera-Salgado,
J. Barrera-Rojas, E. Ríos-Castro, E. B. Gutiérrez-Cirlos., and Obsahuje bibliografické odkazy
The paper presents a survey of the metacercariae of trematodes found in 581 fishes of 15 species from 39 cenotes (sinkholes) of the Yucatan Peninsula, southeastern Mexico. The following 21 species were found: Echinochasmus sp. 1, Echino-chasmus sp. 2, Echinostomatinae gen. sp. (family Echinostomatidae), Stunkardiella minima (Stunkard, 1938), Alrophecaecum (?) astorquii (Watson, 1976), Peiaezia loossi (Pérez Vigueras, 1957) (Acanthostomidae); Ascocotyle (Ascocotyle) tenuicollis Price, 1935, Ascocotyle (Ascolotyle) sp. 1, Ascocotyle (Phagicola) diminuta (Stunkard et Haviland, 1924), Ascocotyle (Phagicola) sp. 2 (= Phagicola angrense Travassos, 1916 of Salgado-Maldonado and Aguirre-Macedo, 1991), Ascocotyle (Phagicola) sp. 3 (Heterophyidae); Cladocystis trifolium (Braun, 1901) (Opisthorchiidae); Oligogonotylus manieri Watson, 1976 (Cryptogonimidae); Clinostomum cf. complanatum (Rudolphi, 1814) (Clinostomidae); Diplostomum (Auslrodiplostomum) com-paclum (Lutz, 1928), Posthodiplostomum minimum (MacCallum, 1921), Posthodiplostomum sp. (Diplostomidae); Neodiplos-tomidae gen. sp. 1 ; Neodiplostomidae gen. sp. 2 (Neodiplostomidae); and Apharyngostrigea sp. (Strigeidae). All species found are described and figured, and their life cycles are briefly discussed.
During a survey of the parasites of freshwater fishes from cenotes (sinkholes) of the Yucatan Peninsula the following species of monogeneans were found on cichlid, pimelodid, characid and poeciliid fishes: Sciadicleithrum mexicanum Kritsky, Vidal-Martinez et Rodriguez-Canul, 1994 from C.ichlasoma urophthalmus (Giinther) (type host), Cichlasoma friedrichsthali (Heckel), Cichlasoma octofasciatum (Regan), and Cichlasoma synspilum Hubbs, all new host records; Sciadicleithrum meekii Mcndoza-Franco, Scholz et Vidal-Martinez, 1997 from Cichlasoma meeki (Brind); Urocleidoides chavarriai (Price, 1938) and Urocleidoides travassosi (Price, 1938) from Rhamdia guatemalensis (Günther); Urocleidoides costaricensis (Price et Bussing, 1967), Urocleidoides heteroancistrium (Price et Bussing, 1968), Urocleidoides anops Kritsky et Thatcher, 1974, Anacanthocotyle anacanthocolyle Kritsky et Fritts, 1970, and Gyrodaclylus neotropicalis Kritsky et Fritts, 1970 from Aslyanax fasciatus; and Gyrodactylus sp. from Gambusia yucatana Regan. Urocleidoides chavarriai, U. travassosi, U. costaricensis, U. heteroancistrium, U. anops, Anacanthocotyle anacanthocotyle and Gyrodactylus neotropicalis are reported from North America (Mexico) for the first time. These findings support the idea about the dispersion of freshwater fishes and their monogenean parasites from South America through Central America to southeastern Mexico, following the emergence of the Panamanian isthmus between 2 and 5 million years ago.
This paper comprises a systematic survey of larval nematodes collected from fishes from cenotes (= sinkholes) of the Peninsula of Yucatan, southern Mexico, in 1993-1994. Larvae of the following nine species were recorded: Physocephalus sexa-lalus, Acuariidae gen. sp., Spiroxys sp., Falcausira sp., Hysterothylacium cenotae, Contracaecum sp. Type 1, Contracaecum sp. Type 2, Goezia sp., and Eustrongylides sp. Larvae of P. sexalatus are recorded from fishes (Rhamdia guatemalensis) for the first time. The larvae are briefly described and illustrated and problems concerning their morphology, taxonomy, hosts and geographical distribution are discussed. Adults of these larvae are parasitic in piscivorous fishes, reptiles, birds and mammals (definitive hosts). Fishes harbouring the larvae of these parasites serve as paratenic hosts, being mostly an important source of infection for the definitive hosts.
The present paper comprises a systematic survey of adult nematodes collected from fishes from cenotes (= sinkholes) of the Peninsula of Yucatan, southeastern Mexico, in 1993-1994. Examinations of a total of 533 fishes (17 species) originating from 39 cenotes from the Mexican states of Yucatan and Quintana Roo revealed the presence of the following nine nematode species: Rhabdochona (Rhabdochona) kidderi, Procamallanus (Spirocamallanus) rebecae, P. (S.) neacaballeroi, Philome-trnides caudata, Hysterothylacium cenotae, Pseudocapillaria yucatanensis, Paracapillaria rhamdiae, P. teixerafreitasi and Capillostrongyloides sp. (only females). Four species (R. kidderi, P. rebecae, P. neacaballeroi and Capillostrongyloides sp.) are briefly described and illustrated and some problems concerning their morphology, taxonomy, hosts and geographical distribution are discussed. Taxonomic changes include Procamallanus (Spirocamallanus) neacaballeroi (Caballero-Deloya, 1977) comb. n. and Procamallanus (Spirocamallanus) rebecae (Andrade-Salas, Pineda-López ct Garcfa-Magana, 1994) comb. n. The nematode fauna of fishes in cenotes of the Yucatan Peninsula shows its appurtenance to the Neotropical fauna with close affinities with that of fish nematodes from South America, but with a considerable degree of endemism.
While investigating the parasites of several marine fishes from the Western Atlantic, the Southern Gulf of Mexico and Central America (Panama), the following monogenoidean species from the gills of gerreid fishes (Gerreidae) were found: Diplectanum gatunense sp. n. (Diplectanidae) and Octouncuhaptor eugerrei gen. et sp. n. (Dactylogyridae) in Eugerres brasilianus (Cuvier) from Gatun Lake in the Panama Canal Watershed, and Diplectanum mexicanum sp. n. in Diapterus rhombeus (Cuvier) from the coast of Campeche State, Mexico. New diplectanid species are distinguished from other species of the genus by the general morphology of the copulatory complex and by the shape of the anchors and bars on the haptor. Octouncuhaptor gen. n. is proposed for its new species having slightly overlapping gonads (testis posterodorsal to the ovary), a dextrolateral vaginal aperture, a copulatory complex consisting of a coiled male copulatory organ with counterclockwise rings with the base articulated to the accessory piece, 8 pairs of hooks and the absence of anchors and bars on haptor. Our analysis of morphological features of Diplectanum species on gerreids evidences that these parasites more closely resemble each other than the known species from sciaenids suggesting that split between gerreids and sciaenids resulted in parasite speciation.
A new cucullanid nematode, Dichelyne mexicanus sp. n., is described from the intestine of three species of fishes, Agonostomus monticola (Bancroft) (Mugilidae, Perciformcs) (type host), Ictalurus balsanus (Jordan et Snyder) (Ictaluridac, Siluriformes) and Cichlasoma beani (Jordan) (Cichlidae, Perciformes), from three rivers (la Maquina River, Veracruz; Chontalcoatlán River, Guerrero and Santiago River, Nayaril) in central Mexico. This species is characterised by the absence of a ventral sucker in the male (subgenus Dichelyne) and it differs from its congeners mainly in possessing very unequal and dissimilar spicules (left 0.465-0.768 mm and right 293-548 mm long), an asymmetrical gubernaculum, and two intestinal caeca. Another cucullanid nematode, Cucullanus cabaUeroi Petter, 1977, is reported from Dormitator maculalus (Bloch) (Eleotridae, Perciformes) from the La Palma and La Maquina Rivers and Balzapote stream, Veracruz, being briefly described and illustrated; this represents a new host record. Findings of D. mexicanus and C. cabalteroi represent a new record of cucullanid nematodes from fishes in Mexican fresh waters.
A new nematode species, Philometroides caudata sp.n., is described from the swimbladder (under the serosa cover) of the freshwater pimelodid catfish, Rhamdia guatemalensis, from cenotes (— sinkholes) in Yucatan, southeastern Mexico. It differs from all hitherto known members of the genus, except P. maplestoni (Travassos, Artigas et Pereira, 1928), in having the functional anus, the conical tail with a terminal knob-like structure and the oesophagus without an anterior inflation in female, and in the structure of the caudal end in male. It can be distinguished from P. maplestoni (described only from females) by the extent of embossed cuticle, the size of body and the host type. P. caudata, representing a Neotropical element, is the first Philometroides species reported from freshwater fishes in Mexico.
A new nematode species, Pseudocapillaria yucatanensis sp. n., is described from the intestine of the freshwater pimelodid catfish Rhamdia guatemalensis (Günther) from cenotes (= sinkholes) in Yucatan, Mexico. It differs from other three related species parasitizing freshwater fishes mainly in possessing the spicule with a simple rim of its proximal end and a non-expanded distal end, in the length of the spicule (0.218-0.295 mm), and the size (0.050-0.060 x 0.025-0.030 mm), shape and structure of eggs, and also in the host types and geographical distribution. Pseudocapillaria yucatanensis is the first known autochtonous species of Pseudocapillaria parasitizing freshwater fishes in Mexico.