An intriguing,new planarian species from Tasmania,with a discussion on protandry in triclad flatworms (Platyhelminthes,Tricladida)

An account is given of an unusual new species of freshwater planarian from the Hartz Mountains in Tasmania, Australia, Romankenkius flaccidus Sluys, sp. nov. The species is characterized, among other features, by an asymmetrical penis papilla, an extremely large, elongated copulatory bursa, and by the absence of testes in animals with fully developed male and female copulatory apparatus. Instigated by the sexual cycle of this new species, the study opportunely reviews whether planarian flatworms generally are simultaneous or sequential—in particular protandrous—hermaphrodites. It is concluded that real protandry does not occur in triclads and that even less extreme cases of sexual segregation, such as complete reduction of the testes or the more or less complete separation of male and female functionality as present in some species, have only sparsely and convergently evolved within the group of the triclad flatworms.     

The morphology and life-cycle of Trichobilharzia parocellata (Johnston & Simpson, 1939) Islam & Copeman, 1980 from the visceral blood vessels of Australian anatids

Summary The morphology of Trichobilharzia parocellata from the portal and mesenteric blood vessels of Anas gibberifrons and A. superciliosa from northern Australia is described. The life-cycle was completed in domestic Muscovy ducks exposed to Cercaria parocellata from naturally infected Lymnaea lessoni. Adults of T. parocellata are distinguished from closely related species by the point of caecal reunion in the male, the number of testes, the nature of the tegument and the species of snail hosts. The miracidia differed from all others in the genus except T. indica in having a pair of coarsely granular posterior secretory glands, a pair of apical glands, a papilla on each side in front of the lateral processes and 18 to 20 germinal cells in a single germinal mass. The prepatent period of T. parocellata in Muscovy ducks was only 11 days after exposure. Pigeons did not become infected. ac]19840624     

Otiorhynchus sulcatus, an autopolyploid general-purpose genotype species?

The weevil Otiorhynchus sulcatus is a pest species that has spread rapidly to large parts of the world due to human activities. O. sulcatus is extremely polyphagous and found to attack a large number of agricultural and horticultural plant species despite that all individuals are clonal triploid females. I here compare the genetical variation in specimens from various parts of the distribution using both mtDNA and nuclear DNA. The genetical markers employed indicate O. sulcatus to be an evolutionary young clonal species of non-hybrid origin. The extreme polyphagy and ecological success indicate that these weevils may well be a prime example of general purpose genotypes.     

Sobolevitaenia japonensis n. sp. (Dilepididae: Dilepidinae) from a dusky thrush, Turdus naumanni eunomus Temminck, in Oita Prefecture, Japan

Sobolevitaenia japonensis n. sp. (Cestoda: Dilepididae) is described from eight specimens from the small intestine of a dusky thrush, Turdus naumanni eunomus Temminck, collected at Beppu City, Oita Prefecture, Japan. S. japonensis most closely resembles S. moldavica among the 11 species now assigned to the genus Sobolevitaenia, from which it is distinguished by a smaller number of proglottids, a larger scolex and a smaller number of testes of larger size, and a larger vitelline gland.     

Testes size, ejaculate quality and sperm competition in birds

The relationship between testes size, ejaculate quality (volume, sperm concentration, number of sperm per ejaculate) and sperm competition in birds was analysed using data collected in artificial insemination studies. I hypothesized that ejaculate quality, because of natural selection, should be superior in species with intense sperm competition compared with other species. In regression analyses, testes weight increased with body weight, with an exponent less than one, and ejaculate volume increased with testes weight with an exponent not significantly different from one, whereas sperm number per ejaculate increased with testes weight with an exponent larger than one. Species with relatively large testes also produced ejaculates with a high sperm concentration. Monogamous species with a relatively low intensity of sperm competition copulate rarely, but deliver ejaculates with a relatively large number of sperm. Monogamous species with a high intensity of sperm competition copulate frequently, but produce ejaculates with a relatively small number of sperm. Males of polygynous species, which also experience intense sperm competition, copulate rarely with specific females, but produce many ejaculates per male each with a relatively small number of sperm.     

Life history, ecology and parasite community structure in Soviet birds

The paper describes an investigation of parasite richness in relation to host life history and ecology using data from an extensive survey of helminth parasites (cestodes, trematodes and nematodes) in Soviet birds. Correlates of parasite richness (number of parasite species per host species) were sought among 13 life-history variables, 13 ecological variables and one non-biological variable (number of host individuals examined) across a sample of 158 species of host. A statistical method to control for the effects of phylogenetic association was adopted throughout. Parasite richness correlates positively with the number of hosts examined (sample size) in all three parasite groups. Positive correlations (after controlling for the effects of sample size) were also found between host body weight and parasite richness for trematodes and nematodes, but not for cestodes.
A number of ecological variables were associated with parasite richness. However, when the effects of sample size and body weight were controlled for, only a single significant correlation (an association between trematode richness and aquatic habitat) remained. Similarly, a number of significant correlates of parasite richness were found among the life-history variables examined. Though several of these were robust to the confounding effects of sample size, all could be explained by the co-variation between life-history traits and body weight among the host species under investigation.     

A natural hybrid newt, Triturus helveticus×T. vulgaris, from a pond in mid-Wales

The first unequivocal example of a natural Trilurus helvelicus × T. vulgaris hybrid is described. The specimen was a male and discriminant analysis of physical characters indicated that it was morphologically intermediate between the parent species. A karyotype confirmed that the hybrid bore a haploid set of chromosomes from T. helveticus and a haploid set from T. vulgaris. Examination of the sex chromosomes showed that it was the result of mating between a male T. helveticus and a female T. vulgaris. As numerous mature sperm bundles were observed in both testes, the hybrid was therefore potentially fertile.     

Two new species of Acanthobothrium Beneden, 1849 (Tetraphyllidea: Onchobothriidae) from horn sharks in the Gulf of California,Mexico

Between 1993 and 1996, 26 individuals of two species of horn sharks were collected from the upper Gulf of California and their spiral intestines examined for onchobothriid tapeworms. Heterodontus francisci was found to host Acanthobothrium puertecitense n. sp. Based on the criteria of Ghoshroy & Caira (2001), this is a Category 4 species (with >15mm total length, >50 proglottids, >80 testes and a symmetrical ovary). It differs from the four Category 4 species previously reported from either the western Atlantic or eastern Pacific Oceans, including A. bajaense (emend.) which was described from H. francisci, in hook-shape, total length, number of proglottids, number of testes and number of columns of vitelline follicles. H. mexicanus was found to host Acanthobothrium santarosaliense n. sp., which, based on the criteria of Ghoshroy & Caira (2001) is a Category 3 species (with >15mm total length, >50 proglottids, >80 testes and an asymmetrical ovary). A. santarosaliense differs from the five Category 3 species previously reported from either the western Atlantic or eastern Pacific Oceans in its size, euapolytic nature, lack of dark matrix from the bases of the hooks, hook-shape, and distribution and number of testes. In addition to the difference in ovarian symmetry, A. puertecitense possesses fewer testes, fewer proglottids, is a shorter worm, possesses a more anterior genital pore and vitelline follicles which extend further forward anteriorly than in A. santarosaliense. This represents the first report of onchobothriids from H. mexicanus and the first report of onchobothriids from H. francisci in the Gulf of California. The apparent host-specificity of both new species should be viewed with caution until a greater sample of host individuals of both species can be examined. The fact that both new tapeworm species are known only from the Gulf is also considered to be a preliminary result, given the small sample of host individuals examined from these regions to date. This brings the total number of species of Heterodontus known to host Acanthobothrium to four and the total number of Acanthobothrium species described from heterodontiform sharks to five.     

A new pronocephalid, Pleurogonius tortugueroi n. sp. (Digenea), from the intestine of green sea turtles (Chelonia mydas) in Costa Rica

A new species of trematode, Pleurogonius tortugueroi n. sp. (Digenea: Pronocephalidae) is described from the lower intestine of green sea turtles (Chelonia mydas) from Tortuguero National Park, Costa Rica. The new species differs from all other species of Pleurogonius by having a short oesophagus and oval testes close to lateral posterior limit of the body. It differs from all other species, except P. malaclemys Hunter 1961, by having an ovary between the testes; moreover the latter species is a parasite of freshwater turtles. All others members of the genus have a long oesophagus, testes placed to some distance from the posterior end, and the ovary is pretesticular. The new species appears most closely related to P. linearis Looss, 1901 but differs from it by having a different body shape, lappets of the head collar close at the cecal bifurcation level, a longer vitellarian field, different testis shape and position, ovary intertesticular, and different egg size.     

Larger testes are associated with a higher level of polyandry, but a smaller ejaculate volume, across bushcricket species (Tettigoniidae)

While early models of ejaculate allocation predicted that both relative testes and ejaculate size should increase with sperm competition intensity across species, recent models predict that ejaculate size may actually decrease as testes size and sperm competition intensity increase, owing to the confounding effect of potential male mating rate. A recent study demonstrated that ejaculate volume decreased in relation to increased polyandry across bushcricket species, but testes mass was not measured. Here, we recorded testis mass for 21 bushcricket species, while ejaculate (ampulla) mass, nuptial gift mass, sperm number and polyandry data were largely obtained from the literature. Using phylogenetic-comparative analyses, we found that testis mass increased with the degree of polyandry, but decreased with increasing ejaculate mass. We found no significant relationship between testis mass and either sperm number or nuptial gift mass. While these results are consistent with recent models of ejaculate allocation, they could alternatively be driven by substances in the ejaculate that affect the degree of polyandry and/or by a trade-off between resources spent on testes mass versus non-sperm components of the ejaculate.     

Five new species of Acanthobothrium (Tetraphyllidea: Onchobothriidae) from the freshwater stingray Himantura chaophraya (Batoidea: Dasyatidae) in Malaysian Borneo

Five new species of Acanthobothrium (Tetraphyllidea: Onchobothriidae) are described from the spiral intestine of the Freshwater whipray, Himantura chaophraya, in the Kinabatangan River in Malaysian Borneo. Based on criteria set forth in a previous categorization scheme for species of Acanthobothrium, these consist of 3 Category 1 species, Acanthobothrium asnihae n. sp., Acanthobothrium saliki n. sp., and Acanthobothrium zainali n. sp.; a Category 8 species, Acanthobothrium etini n. sp.; and a Category 2 species, Acanthobothrium masnihae n. sp.. Acanthobothrium asnihae n. sp. differs from all Category 1 species in its possession of a horizontal band of weak musculature that divides the posterior loculus in half. Among Category 1 species, A. saliki n. sp. differs from all but Acanthobothrium southwelli in its possession of postovarian testes. It differs from A. southwelli in its possession of fewer testes and a greater number of proglottids. Acanthobothrium zainali n. sp. differs from the 25 other Category 1 species in a combination of overall size, muscular pad and hook shape, arrangement and number of testes, ovary configuration in cross section, position of ovarian isthmus, and genital pore position. Acanthobothrium etini n. sp. is distinguished from all 5 other Category 8 species in its lack of testes from the proglottid antiporal and postporal regions and in testis number. Acanthobothrium masnihae n. sp. differs from the 35 other Category 2 species in its possession of fewer testes, postporal testes, or a greater number of proglottids. A key to Acanthobothrium species parasitizing H. chayophraya is presented. This represents the first report of Acanthobothrium from freshwater stingrays belonging to a family other than the Potamotrygonidae.     

Separate and distinctive roles for Wnt5a in tongue, lingual tissue and taste papilla development

Although canonical Wnt signaling is known to regulate taste papilla induction and numbers, roles for noncanonical Wnt pathways in tongue and taste papilla development have not been explored. With mutant mice and whole tongue organ cultures we demonstrate that Wnt5a protein and message are within anterior tongue mesenchyme across embryo stages from the initiation of tongue formation, through papilla placode appearance and taste papilla development. The Wnt5a mutant tongue is severely shortened, with an ankyloglossia, and lingual mesenchyme is disorganized. However, fungiform papilla morphology, number and innervation are preserved, as is expression of the papilla marker, Shh. These data demonstrate that the genetic regulation for tongue size and shape can be separated from that directing lingual papilla development. Preserved number of papillae in a shortened tongue results in an increased density of fungiform papillae in the mutant tongues. In tongue organ cultures, exogenous Wnt5a profoundly suppresses papilla formation and simultaneously decreases canonical Wnt signaling as measured by the TOPGAL reporter. These findings suggest that Wnt5a antagonizes canonical Wnt signaling to dictate papilla number and spacing. In all, distinctive roles for Wnt5a in tongue size, fungiform papilla patterning and development are shown and a necessary balance between non-canonical and canonical Wnt paths in regulating tongue growth and fungiform papillae is proposed in a model, through the Ror2 receptor.     

Fruit production,migrant bird visitation,and seed dispersal of Guarea glabra in Panama

Summary The relationship between bird visitation and the size of the available fruit crop was studied at an understory tree (Guarea glabra Vahl, Meliaceae) in the tropical wet forest of Barro Colorado Island, Panama Canal Zone. Twelve resident species and seven North American migrant species fed on the Bright orange arilloids (seeds with arils), which were not depleted during the normal fruiting period. The number of individual visitors, the number of visiting species, and the number of seeds removed increased linearly with the size of the available fruit crop. The proportion of seeds removed did not increase with the size of the available fruit crop, indicating that dispersal is a function of the number of fruit available and not a disproportionate function of large fruit displays. Four species of North American migrants (Myiarchus crinitus, Catharus ustulatus, Vireo olivaceus, and Vermivora peregrina) accounted for 70% of the visits and 60% of the seeds removed from the trees. No resident species visited Guarea as frequently as any one of these migrants. There was no indication that any single visitor was dependent on this tree for nutrition, nor that the tree was dependent upon any single species for dispersal. We hypothesize that the fruiting season of G. glabra is adaptively synchronized with northward migration of opportunistically frugivorous North American birds.     

Petasiger oschmarini n. sp. (Digenea: Echinostomatidae) in the grebes Podiceps grisegena (Bod.) and P. auritus (L.) (Aves: Podicipedidae) from Kamchatka,Russia

A re-examination of three sets of trematodes collected in two species of grebes, Podiceps grisegena and P. auritus, from the Kamchatka region of eastern Russia, previously identified as Petasiger neocomense, revealed that they actually represent a new species, which is named Petasiger oschmarini. Characteristic morphological features of the new species include: a head collar possessing a constant number of 19 spines; a large cirrus-sac comparable in size to the ventral sucker, containing a bipartite seminal vesicle and a well-developed pars prostatica; a large bulb-like cirrus similar in size to the testes; a long forebody; a long oesophagus; testes situated obliquely or symmetrically; and lateral vitelline fields which are not confluent in the forebody. The new species is distinguished from all Palaearctic and Nearctic members of Petasiger which possess 19 collar spines. The material described by Oschmarin (1950) as P. neocomense is considered to be conspecific.