Urocleidoides spp. (Monogenea: Dactylogyridae) from the gills of Parodon nasus (Characiformes: Parodontidae) from a Brazilian stream with descriptions of two new species

Urocleidoides spp. are reported from the gills of 20 specimens of Parodon nasus (standard length 8.5–12 cm), from the Indiana stream, Tietê River, Upper Paraná River basin, municipality of Botucatu, São Paulo State, Brazil. Urocleoidoides tenuis and two new species were found. Urocleidoides indianensis n. sp. differs from its congeners mainly by the morphology of the vaginal sclerite that is robust, sickle-shaped, and forked at the distal end; and by the bulbous-shaped accessory piece of the male copulatory complex. Urocleidoides parodoni n. sp. resembles U. tenuis by presenting male copulatory organ with approximately 7 ½ counterclockwise rings, but differs by the morphology of the accessory piece (lobate with a small hook-like projection versus pincer-shaped), vaginal sclerite (thumb-like subterminal projection vs. presence of a distal hook), vaginal tube (conspicuously sclerotized vs. slightly sclerotized), shape of the ventral bar (bowed vs. wide V-shaped), ventral and dorsal anchors (robust base and short shaft vs. considerably less robust base and long shaft), and hooks (slender shank with a weakly sclerotized subunit at base vs. dilated shank). Sequences of the partial 28S rDNA gene of the dactylogyrids found in this study are provided. Phylogenetic analyses showed Urocledoides spp. from Parodontidae clustering together with strong support values. This study increases the number of valid Urocleidoides species to 39, and the number of species described from parodontid hosts to four.

Male genital lobe morphology affects the chance to copulate in Drosophila pachea

Introduction Male genitalia are thought to ensure transfer of sperm through direct physical contact with female during copulation. However, little attention has been given to their pre-copulatory role with respect to sexual selection and sexual conflict. Males of the fruitfly Drosophila pachea have a pair of asymmetric external genital lobes, which are primary sexual structures and stabilize the copulatory complex of female and male genitalia. We wondered if genital lobes in D. pachea may have a role before or at the onset of copulation, before genitalia contacts are made. Results We tested this hypothesis with a D. pachea stock where males have variable lobe lengths. In 92 mate competition trials with a single female and two males, females preferentially engaged into a first copulation with males that had a longer left lobe and that displayed increased courtship vigor. In 53 additional trials with both males having partially amputated left lobes of different lengths, we observed a weaker and non-significant effect of left lobe length on copulation success. Courtship durations significantly increased with female age and when two males courted the female simultaneously, compared to trials with only one courting male. In addition, lobe length did not affect sperm transfer once copulation was established. Conclusion Left lobe length affects the chance of a male to engage into copulation. The morphology of this primary sexual trait may affect reproductive success by mediating courtship signals or by facilitating the establishment of genital contacts at the onset of copulation.

A New Monogenean-ectoparasites Silurodescoides srivastavai n.sp. From Edible Fresh-water Cat Fish Wallago attu of District Balrampur, Uttar Pradesh, India.

The fresh-water fish Wallago attu (Bloch. And Schn.) was collected from local fish market of district Balrampur (U.P.) and examined 15 specimens, of which only one specimen was found infected with 17 specimens of said species. The site of infection being the gill filaments of the host. The present form differs from S. devraji, S. malabaricus and S.parvulus in having accessory pieces on dorsal anchors and presence of wings on dorsal anchors. Moreover, it differs from S. indicus, S octolytus, S. aori and S. sudhakari in having cephalic glands and different shape of copulatory complex and vagina. On subsequent study, the present form appear to be a new species of the genus Silurodescoides Gussev, 1974 and described as a new species and named Silurodescoides srivastavai n. sp. in the honor of Dr. C.B. Srivastava, Ex. Dy. Director, Zoological Survey of India, Kolkata.

Monogenoids (Polyonchoinea, Dactylogyridae) from Hydrolycus armatus (Characiformes, Cynodontidae) with the description of a new species of Rhinoxenus and the proposal of a new genus from the Xingu River, Pará, Brazil

One new species of Rhinoxenus Kritsky, Boeger & Thatcher, 1988 from the nasal cavities and four new species of Mymarothecioides n. gen. from the gills are described in Hydrolycus armatus (Jardine & Schomburgk). They were collected in the Xingu River, Pará, Brazil. Rhinoxenus cachorra n. sp. is characterized by having a ventral anchor with inconspicuous roots, and point with fish-hook-like termination; copulatory complex comprising a spiraled male copulatory organ (MCO) with two counterclockwise coils, and an accessory piece with an expanded, bifurcated distal portion. Mymarothecioides n. gen. is proposed and characterized for species without eyes, with or without accessory chromatic granules; copulatory complex comprising articulated MCO, accessory piece; MCO a broad arcuate tube; an accessory piece with a hooked termination in the distal portion; a dextro or midventral non-sclerotized vagina; an anteromedial projection on the ventral bar. Mymarothecium whittingtoni Kritsky, Boeger & Jégu, 1996 is transferred to Mymarothecioides n. gen. as Mymarothecioides whittingtoni (Kritsky, Boeger & Jégu, 1996) n. comb.

Male genital lobe morphology affects the chance to copulate in Drosophila pachea

IntroductionMale genitalia are thought to ensure transfer of sperm through direct physical contact with female during copulation. However, little attention has been given to their pre-copulatory role with respect to sexual selection and sexual conflict. Males of the fruitfly Drosophila pachea have a pair of asymmetric external genital lobes, which are primary sexual structures and stabilize the copulatory complex of female and male genitalia.ResultsWe tested for a pre-copulatory role of these lobes with a D. pachea stock where males have variable lobe lengths. In 92 mate competition trials with a single female and two males, females preferentially engaged into a first copulation with males that had a longer left lobe and that displayed increased courtship vigor. In 53 additional trials with both males having partially amputated left lobes of different lengths, we observed a weaker and non-significant effect of left lobe length on copulation success. Courtship durations significantly increased with female age and when two males courted the female simultaneously, compared to trials with only one courting male.ConclusionLeft lobe length affects the chance of a male to engage into copulation. The morphology of this primary sexual trait may affect reproductive success by mediating courtship signals or by facilitating the establishment of genital contacts at the onset of copulation.

Monogenean fauna of alien tilapias (Cichlidae) in south China

Tilapias are important aquaculture fishes that have been introduced widely all over the world, often carrying their monogenean parasites with them. An extensive investigation on monogeneans of invasive tilapias was conducted in 19 natural water sources in south China between July 2015 and December 2017. We found nine known species of monogeneans, i.e., Enterogyrus coronatus, E. malmbergi, Cichlidogyrus cirratus, C. halli, C. sclerosus, C. thurstonae, C. tilapiae, Scutogyrus longicornis, Gyrodactylus cichlidarum, and one unknown Gyrodactylus species. In addition to reporting ten new hosts and four new geographical records, we observed new morphological characteristics of these species. Observation on living specimens of Enterogyrus spp. demonstrated that these two species have characteristic opisthaptoral retraction capacities, while the opisthaptor glands were not observed in our specimens of E. coronatus and E. malmbergi. The morphological differences of the accessory piece of the male copulatory complex between C. cirratus and C. mbirizei (character for species differentiation) could result from the observation at different perspectives, which indicates that C. mbirizei is likely a synonym of C. cirratus. A more detailed structure of the sclerotized parts of Cichlidogyrus spp. and S. longicornis were revealed by scanning electron microscopy. As was the case for the monogeneans found on alien tilapias from other geographic regions, the present study confirmed the high potential of these monogeneans to establish populations in new habitats.

A new genus and species of entocytherid ostracod (Ostracoda: Entocytheridae) from the John Day River Basin of Oregon, U.S.A., with a key to genera of the subfamily Entocytherinae

Targeted sampling efforts by the authors for the signal crayfish, Pacifastacus leniusculus, from its native range in the John Day River Basin, Oregon, U.S.A. yielded entocytherid ostracods with a male copulatory complex so clearly different from other entocytherines that a new genus, Aurumcythere gen. nov. is proposed to receive them. This newly proposed, apparently nonsclerotized, genus with hook and spur-like prominences of the posteroventral end of the peniferum is the first new genus of the subfamily Entocytherinae named since Hobbs & Peters described Aphelocythere (= Waltoncythere) in 1977. Aurumcythere gen. nov. represents only the second genus of entocytherid known from the Pacific Northwest. Lack of sclerotization in Aurumcythere gen. nov. provides new insight into poorly understood mating behaviors of entocytherid ostracods.

STUDY OF MORPHOLOGICAL CHARACTERISTICS OF TAXONOMICALLY SIGNIFICANT AQUATIC AND SEMIAQUATIC FAMILIES IN HETEROPTERA

The heteroptera is an important suborder of order hemiptera and includes a large number of aquatic and semiaquatic forms, which are of a taxonomic importance. The study recorded 14 families namely Napidae, Notonectidae Pleidae, Belostomatidae, Naucoridae, Corixidae, Gelastocoreidae, Ochtaridae, Hydrometridae, Velidae Mesoveliidae, Gerridae, Saldidae and Herbridae. Aquatic and semiaquatic heteropteran insects are of variable sizes from 1.5 mm. to 110 mm long living mainly in lentic and lotic fresh water. Some even live in brackish water, only a few species are marine. These are different in morphology and feeding habits from their terrestrial forms. Some are truly aquatic, provided with effective swimming respiratory structure along with modification of body shape and size. Besides the genitalia and copulatory complex of all the species studied has been dealt. The other morphological features of taxonomic significance were also studied. This study finds various morphological features in the members of different aquatic and semiaquatic families of heteroptera.

First data on the parasites of Hoplias aimara (Characiformes): description of two new species of gill monogeneans (Dactylogyridae)

The first data on the parasites of the giant trahira, Hoplias aimara (Characiformes: Erythrinidae), a little known, but popular fish for sport angling, are provided. In H. aimara from the Xingu River in Brazil, two new species of gill monogeneans of the family Dactylogyridae were found and their description is provided herein. Urocleidoides aimarai n. sp. differs from all 18 congeners by the presence of a large accessory piece of the male copulatory organ and based by morphology of anchors. Urocleidoides xinguensis n. sp. is distinguished by unique combination of copulatory complex and haptoral structures.