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Species of the genus Dormitator, also known as sleepers, are representatives of the amphidromous freshwater fish fauna that inhabit the tropical and subtropical coastal environments of the Americas and Western Africa. Because of the distribution of this genus, it could be hypothesized that the evolutionary patterns in this genus, including a pair of geminate species across the Central American Isthmus, could be explained by vicariance following the break-up of Gondwana. However, the evolutionary history of this group has not been evaluated. We constructed a time-scaled molecular phylogeny of Dormitator using mitochondrial (Cytochrome b) and nuclear (Rhodopsin and β-actin) DNA sequence data to infer and date the cladogenetic events that drove the diversification of the genus and to relate them to the biogeographical history of Central America. Two divergent lineages of Dormitator were recovered: one that included all of the Pacific samples and another that included all of the eastern and western Atlantic samples. In contrast to the Pacific lineage, which showed no phylogeographic structure, the Atlantic lineage was geographically structured into four clades: Cameroon, Gulf of Mexico, West Cuba and Caribbean, showing evidence of potential cryptic species. The separation of the Pacific and Atlantic lineages was estimated to have occurred ~1 million years ago (Mya), whereas the four Atlantic clades showed mean times of divergence between 0.2 and 0.4 Mya. The splitting times of Dormitator between ocean basins are similar to those estimated for other geminate species pairs with shoreline estuarine preferences, which may indicate that the common evolutionary histories of the different clades are the result of isolation events associated with the closure of the Central American Isthmus and the subsequent climatic and oceanographic changes.

Diaphorocleidus orthodusus n. sp. and Diaphorocleidus kabatai (Molnar, Hanek and Fernando, 1974) Jogunoori, Kritsky, and Venkatanarasaiah, 2004 are detailed from Astyanax orthodus and Astyanax aeneus, respectively. Palombitrema heteroancistrium (Price and Bussing, 1968) is described from specimens collected from A. aeneus, and Urocleidoides strombicirrus (Price and Bussing, 1967) is reported for the first time from A. aeneus and Astyanax fasciatus in Panama. Characithecium costaricensis (Price and Bussing, 1967) n. comb. is detailed based on specimens from A. aeneus. Characithecium costaricensis is characterized by having overlapping gonads, a medioventral vaginal aperture, a copulatory complex consisting of single counterclockwise coil of the copulatory organ that is articulated to the accessory piece, and a haptor having 2 pairs of anchors, dorsal and ventral bars, and 14 hooks. Measurements of body size varied substantially among individual worms, both within and across different host species and locations. However, the morphological differences were insufficient to separate species of Characithecium. This result suggests limited parasite speciation across sympatric species of Astyanax in Mexico and Panama.Urocleidoides Mizelle and Price, 1964, was erected for a species that infected Poecilia reticulata (Poeciliidae) in a California aquarium. Mizelle et al. (1968) emended it by adding gonads overlapping or tandem, male copulatory organ coiled with a single or multiple rings, 1 or 2 prostatic reservoirs, and vaginal pore on the left side of the body or absent. Urocleidoides included species from fishes in 5 orders (Atheriniformes, Characiformes, Gymnotiformes, Perciformes, and Siluriformes) until Kritsky et al. (1986) (2007). Additional specimens were mounted unstained in Gray and Wess's medium to examine the sclerotized structures. Measurements, all in micrometers (m), represent straight-line distances between extreme points and are expressed as the mean followed by the range and number (n) of structures measured in parentheses; body length includes the haptor. Numbering of hook pairs follows Mizelle (1936) and Mizelle and Price (1963).

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During an investigation of gill monogenoidean parasites from freshwater fishes in central Panama, 5 new species of Urocleidoides (sensu stricto) were found: Urocleidoides cultellus n. sp., Urocleidoides visiofortatus n. sp., and Urocleidoides advenai n. sp. from the gymnotiform Brachyhypopomus occidentalis (Hypopomidae); Urocleidoides neotropicalis n. sp. and Urocleidoides piriatiu n. sp. from the characiforms Saccodon dariensis (Parodontidae) and Ctenolucius beani (Ctenoluciidae), respectively. Our findings represent the first known species of Urocleidoides from these fishes in Central America and demonstrate that they are morphologically linked to their South American congeners.Urocleidoides Mizelle and Price 1964 (Monogenoidea: Dactylogyridae) (as amended by Kritsky et al., 1986), accommodates species possessing overlapping or tandem gonads, a coiled male copulatory organ with counterclockwise rings, a sinistral vaginal sclerite, unmodified anchors, and similar hooks with dilated shanks, and hooks pairs 1, 5, usually reduced in size. According to this diagnosis, 6 species of Urocleidoides {Uro-cleidoides anops Kritsky and Thatcher, 1974 MATERIALS AND METHODSFishes were collected with the use of electrofishing and trammel nets from Aguas Claras River at its confluence with the Bayano Lake (09°15'05.1"N, 78°41'11.2"W) and Rio Piriati River (09°03'36"N, 78°39'57"W) at its confluence with the Chagres River Basin in central Panama. Methods of collection, preparation of helminths for study, and measurement and illustration follow Mendoza-Franco et al. (2007). To study sclerotized structures, some specimens were mounted unstained in glycerin jelly. Measurements, all in micrometers (p,m), represent straight-line distances between extreme points and are expressed as the mean followed by the range and number (n) of structures measured in parentheses; body length includes the haptor. Numbering (distribution) of hook pairs follows Mizelle (1936; see Mizelle and Price, 1963) Diagnosis: Body fusiform 385 (165-712; n = 4) long, robust; greatest width 64 (41-76; n = 5) usually at level of testis. Cephalic margin broad; cephalic lobes moderately developed; 3 bilateral pairs of head organs; cephalic glands indistinct. Eyespots absent; accessory granules scattered in cephalic region and anterior trunk. Pharynx spherical 13 (12-18; n = 4) in diameter; esophagus moderately long. Peduncle broad; haptor subrectangular, 72 (65-85; n = 3). Ventral anchor 40 (39-43; n = 10) long, with elongate tapered superficial root, short deep root, proximally bent shaft, short point; base 23 (23-24; n = 5) wide. Dorsal anchor 24 (23-25; n = 7) long, poorly differentiated deep root, curved shaft, with bifurcate points; base 15 (15-16; n = 7) wide. Ventral bar 44 (42-47; n = 6) long, wide U-shaped with enlarged terminations; dorsal bar 37 (35-42; n = 4) long, with enlarged ends. Hooks similar, each with recurved point, depressed thumb, dilated shank; hook pairs 1, 5 reduced in size; filamentous booklet (FH) loop half shank length (pairs 1...