Abstract: Parturition in the Costa Rican Epiperipatus hilkae has the following sequence: the mother showed peristalsis and a swollen gonopore, the terminal lobopods are raised and the neonate walks out, a drop of whitish material is expelled by the gonopore and the young crawled to the mother«s back. Four young measured 1.2-1.8 mm in length and weighed 0.010-0.017 g (mean 5.9 % of mogher«s weigth). During the first six weeks young are more lightly colored than adults. In onychophorans, the parturition sequence is realtively constant throughout the taxa, requires 10-30 min and its frecuency appears to be influenced by environmental conditions. The systematic distribution of modes of reproduction suggests and increasing tendency towards greater parental investment.
Abstract: Epiperipatus hilkae, a new species discovered in tropical dry and moist forests (NW Costa Rica) has the following characteristics: in the fourth and fifth oncopods, the nephridial tubercle is free from the third sole, and only partially surrounded by the fourth arc. Each segment has 12 skin folds (seven folds reach the ventral side), which are divided only by the midline. The primary papillae are conical with rouded bases and two to three scale ranks in the apical section. The external jaw blade has two accessory teeth, the internal with one accessory tooth and 12 denticles. The diastema is monolobular. The dorsal part is dark brown with a pattern of hexagons conspicuous for their light reddish-brown papillae. The new species is closely related to E. isthmicola and "E. nicaraguensis", also from Central America. It remains active during the dry season in isolated moist patches.
Abstract:The behavior of Epiperipatus biolleyi Bouvier was studied in the laboratory. In choice tests, bryophyte vegetation and its associated soil were preferred to grass and its soil. In 87 hr the animals chaged artificial burrows 2.89 times. They enter burrows mostly by walking forward and show a tendency to rest facing the entrance. No agressive competition for burrows was observed. Pairs rest with some body contact about half the time. Seven resting body postures were identified. They hide from direct sunlight in 189 s (mean) when placed over moss and appear to avoid light around 470-600 nm. Walking speed was near 1cm/s. They float and become tergid in freshwater but drown in sea water. Their adhesive secretion has a bitter taste and dissolves in less than 3 s in sea water but remains adhesive under freshwater for at least 20 hr. In nature, animals bear scars and mutilated oncopods. Death is often preceded by a retraction of the antennae and expulsion of saliva, adhesive substance, faeces and sometimes embryos. Ecdysis occurs aproximately every 15 days. At least one bird (Turdus grayii) and one snake (Micrurus hemprichii) are known to prey on other onychophoran species in the wild.
Abstract:Epiperipatus biolleyi and Epiperipatus isthmicola from Costa Rica were studied in the laboratory. Morphometric analyses of E. biolleyi show that: (1) larger animals have more legs and (2) females have 8% more pairs of legs, and are 24% longer and 50% heavier than males. An estimation of how alcohol preservation affects body length indicates less shrinkage in females. Physiological observation on E. isthmicola showed that (1) in a session these animals can lose a mean of 7.4% of body weight (BW) by expelling their adhesive secretion, (2) weight loss by water evaporation was in average 2% of BW/min at a 66% relative humidity, and (3) larger animals lose water more slowly. An observed parturition of E. isthmicola had the sequence and timing that are typical of the family Peripatidae.
Abstract:The ecological biogeography of onychophorans has been the subject of some qualitative observations, but the results have been incosistent. Thes paper presents the results of (1) statistical analyses of 172 geographic quadrats for both onychophoran families (worldwide) and (2) independent graphic analyses of most South African and Australian species. Both types of analysis produced different results, including a correlation of occurrence with Pleistocene vegetation, which does not imply causation. Although altitude and rainfall co-relate with the distribution of some South African and Australian taxa, each of the following factors failed to explain by itself the barriers that limit onychophoran distribution at the global level: mean annual rainfall and temperature, photosynthesis, and types of climate, vegetation and biome. The barriers seem to be a product of several ecological factors which depend on the onychophoran taxon.
Abstract: A quantitative analysis of several onychophoran characteristics shows that in habitats with lower rain levels females reproduce at an older age, are more fecund and tend to have reproductive diapause where rain does not exceed a mean of 200 cm/year. These habitat characteristics are associated with the southern family Peripatopsidae. Sex ratio and parental insvestment per yong are not correlated with general environmental conditions. A comparison of 72 species showed that larger species are often more variable in morphometry, but species with the longest females do not always have the longest males. Larger Peripatus acacioi females (Peripatidae: Brazil) produce more and heavier offspring. Intrapopulation morphology was studied in 12 peripatid species for which samples of between 11 and 798 individuals were available. In general, within populations the females are more variable than males in length and weight, but similarly variable in the number of legs. The number of legs has a low variability (1.73-2.45%), length is intermediate (22.4-25.3%) and weight is very variable (49.41-75.17%). When sexes are compared within a population, females can have 1.4-8.9% more leg pairs, and be 47-63% heavier and 26% longer than males.
Abstract: A cladistic analysis places the Onychophora between Polychaeta and Arthropoda. The 'Uniramia' concept is not supported. No justification was found for either onychophoran family to be considered ancestral. A cladogram of fossil genera indicates the common ancestor to have long oncopods, armoured plates and an annulated body. Later forms show adaptations to life in reduced spaces. Physiological data suggest that the Onychophora became adapted to land via the littoral zone, before the Late Ordovician. Adhesive glands evolved for defense on land. Peripatopsidae and Peripatidae were distinct by the late Triassic. The occurrence of onychophorans probably dates from post-Early Cretaceous in Chile, the southern half of Southeast Asia, Mesoamerica and the Caribbean. After the Early Cretaceous, the peripatids of tropical Africa lost terrestrial contact with those of South America. A new biogeographic technique, formalized here under the name retrovicariance, indicates that the Peripatidae of Equatorial Africa and the Neotropics are sister-groups. Typical inbreeding adaptation found in some onychophorans include: female-biased sex ratios; gregarious development; relatively constant time of development and number of offspring in each clutch; male polygamy and shorter life span; frequent sibmating in the microhatibat of development, and sperm storage by females, so that a single insemination fertilizes all ova.
Abstract: Habitat characteristics were compared for 20 onychophoran localities in Costa Rica, from the seasonally dry western Pacific forest to the rainforests of the Caribbean. Everywhere, rainfall is more variable than temperature and than relative atmospheric humidity. A microhabitat study of Epiperipatus biolleyi Bouvier, 1902 was done for comparison with the only other species for which equivalent data are available, the Brazilian Peripatus acacioi. The Costa Rican species was found (1) in sandy, not clay rich soil, (2) closer to the surface and (3) in burrows whose temperature es more similar to the external air temperature. For both species the soil humidity (mean 35 %) and acidity (pH=5.2-6.2) were similar. T he maximum E. biolleyi population density was 0.25 individuals/m2. No clearcut trends in associated flora and fauna were found. In the laboratory, the animals preferred rotten to non-rotten wood, and water-soaked soil to oven-dried soil, during periods of inactivity.
Abstract: A comparison with another group of terrestrial predatory invertebrates, the Order Scorpiones, suggests that the lack of adaptations to dry microenvironments has been the central limitation to further biogeographic radiation in the phylum Onychophora.
Abstract: Summary paleomaps of global continental vegetation from the Jurassic through the Pliocene were prepared (based on the literature) and used to define an area cladogram. Bouvier's (early XX century) natural classification of velvet worms (phylum Onychophora) was used to define an independent taxonomic/geographic cladogram of onychophorans for all regions where they are found today. Both cladograms show the same sequence of geographic vicariance. Thus, the paleogeographic model is supported by the taxonomic evidence. The paper includes a color atlas.
Abstract: The basic behaviour of Epiperipatus biolleyi Bouvier 1906 was studied experimentally in the laboratory with specimens collected in the central plateau of Costa Rica (Coronado area of San José province). The animal avoids light of a wave length between 470 and 600 nm. Perhaps it lacks the ability to detect light in the infrared and ultraviolet light range, suggesting that the wider visual range of insects- for instance- was acquired later in arthropodan evolution.
Abstract: We are studing Euperipatoides rowelli (Reid 1996) as a model of population processes at increasing spatial scale from local patterns of mating through to regional phylogeography. This onychophoran is cornmon in rotting logs in forests of southeastern New South Wales (NSW), Australia (Reid 1996). Allozymes identify regional cryptic species, but are unusually invariant at finer scales (Tait et al. 1995), and therefore we cloned microsatellites which could be expected to be more variable. Under standard conditions, only loci P6 and P23 gave scoreable polymorphic patterns of the expected size (Table 1). (These loci work well in duplex if the primer concentrations of P6 are doubled.) Primers for P17 gave poor aniplification of the (CA)14 170 bp target, but yielded two other polymorphic loci: 'P17 low' and 'P17free' (there is no linkage disequilibrium between these, P > 0.05 in all populations). Shorter P17 primers (Table 1) give better results for P17low. P18 could not be made to amplify until we added 0.01% final Tween 20 and Nonidet P40 detergents, with which the locus is scoreable. Consistency with Mendelian inheritance of the five loci has been confirmed in mother-offspring and population samples. Some loci do not amplify at all in sorne populations (Table 1), probably because E. rowelli is a species complex: adjacent populations can differ by 20% (or more in mtDNA COI sequence (P. Sunnucks, unpublished). P6 and P23 have nonamplifying alleles, including in the population from which they were cloned.
Abstract: Onychophorans (peripatus or velvet worms) show extraordinarily high local endemism, and cryptic species are common. As part of a programme addressing issues of endemicity at hierarchical spatial scales, we investigated reproduction in Euredratoides rowelli (Onychophora: Feripatopsidae) using microsatellite analysis. This species is ovoviviparous, and females have up to 70 embryos in their uten simultaneously Batches of undeveloped and well-developed embryos may be present in the uten of a female. Paired ovaries lead via a common oviduct into paired uteri, each of which has a spermatheca (sperm storage organ). Insemination in E. rowelli is dermal-haemocoelic: spermatophores are placed on the skin of the female, the body wall is breeched, and sperm are released into the haemocoel through which they migrate to the spermathecae. There is no obvious mechanism to prevent sperm mixing, yet microsatellite analysis indicated that offspring in a female's paired reproductive tracts can be sired by different males, and that the paired spermathecae can contain sperm from different males. More than 70% of females had broods with multiple paternity. The data are consistent with the potential for female postcopulatory influence over fertilizations: in particular, compadmentalization of sperm from different males into different spermathecae. Female control of fertilizations could lead to benefits including increased diversity of offspring, minimization of maternal-paternal genetic incompatibility, and influence on offspring genotvpes. Multiple mating alone may increase Ihe genetic diversity of offspring: this could be of importance in E. rowelli, which has very small genetic neighbourhoods and low genetic marker diversity.
Abstract:The following new records are report for Peruvian tropical forest:Oroperipatus weyrauchi at Parque nacional Yanachaga-Chemillén, Pasco (one specimen); Oroperipatus bluntschlii from Río Lagartococha, Loreto (three specimens) and Oroperipatus quitensis, Cordillera del Cóndor, Amazonas (one specimen). They are deposited in the Entomological Collection, Museo de Historia Natural, Universidad Mayor de San Macos, Perú.
Abstract: Tertiapatus dominicanus n.g., n.sp. (Tertiapatidae n.fam.) andSuccinipatopsis balticus n.gen., n.sp. (Succinipatopsidae n.fam.) (Lobopodia: Onychophora), the first Tertiary fossils of the Lobopodia, are described from Dominican and Baltic amber; respectively. Both families are characterized by the presence of simple legs lacking foot portions with claws and pads. Tertiapatidae is further characterized by soluble body pigments and oral papillae shorter than the legs. Succinipatopsidae is characterized by non-soluble body pigments and oral papillae longer than the legs. Nomenclatural changes include the erection of the class Udeonychophora n.nom. for terrestrial onychophorans with a ventral mouth, the order Ontonychophora n.nom. for extant onychophorans possessing legs with a differentiated "foot" portion, and the family Helenodoridae n.nom. for the genus Helenodora from the Carboniferous. The biogeographical significance of these fossils and their phylogenetic relationship with previously described onychophorans are discussed.