Family Erpobdellidae Research Articles

Application of Modern Approaches to Species Delimitation in Freshwater Erpobdellidae (Hirudinea: Arhynchobdellida) with a New Interpretation of Their Genera

The traditional taxonomy of freshwater invertebrates is a labor-intensive process requiring extensive knowledge and experience. In addition, this science is largely subjective, which makes its digitalization difficult. However, accurate species attribution is becoming increasingly important for environmental surveys and conservation efforts. In the 21st century, molecular biology methods have proven to be a successful tool for objectively determining biodiversity. Achieving objectivity in identifying the taxa of non-parasitic leeches of the family Erpobdellidae was the main goal of this study. To this end, various bioinformatic approaches to DNA sequence analysis have been tested. As a result, the phylogenetic diversity amounted to 47 species versus 29 morphospecies defined traditionally. The use of molecular species delimitation methods made it possible to identify seven complexes of morphologically hidden (cryptic) species and some morphological misidentifications, as well as to discover a new species from Eastern Siberia (Erpobdella sibirica) with a unique molecular diagnosis (DNA barcode). A pioneering attempt to apply the same approach to higher taxa showed that Erpobdellidae probably consists of seven genera, including the unambiguous elimination of the genus Motobdella. Obtaining quantitative and, therefore, objective data is an advantage of the molecular approach, which has proven to be effective in recognizing species and genera, at least in leeches.

Dina crnogorensis sp. nov. (Annelida, Hirudinea: Erpobdellidae) – a new leech species from Montenegro

A yellowish spotted and medium-sized new leech of the family Erpobdellidae with a typical annulation of the genus Dina was found in a spring in the northeastern Montenegro. In the present study, we used an integrative taxonomic approach that combines morphological and DNA barcoding data to describe a new species, Dina crnogorensis sp. nov. Morphologically, the new species is most similar to Dina minuoculata Grosser, Moritz & Pešić, 2007 and Dina serbica Pešić & Grosser, 2022 from the same geographical region, but also to D. orientalis Grosser, Nesemann & Pešić, 2011 from the Near and Middle East. Differences in anatomy and the results of species-delimitation analyses based on COI sequences supported species status of the new species.

Genetic variation, pseudocryptic diversity, and phylogeny of Erpobdella (Annelida: Hirudinida: Erpobdelliformes), with emphasis on Canadian species

Leeches of the family Erpobdellidae are important members of benthic freshwater environments, where they are voracious predators of other invertebrates and an important source of nutrition for several species of vertebrates. Beset by a lack of reliable diagnostic morphological characters and destructive identification processes, molecular approaches have, in recent years, been employed to illuminate the relationships within this family, and DNA barcoding has been employed for identification purposes. However, an understanding of the levels of genetic variation across the geographic distributions of members of the genus is still lacking. Herein, we sequence the mitochondrial COI locus for 249 newly collected North American individuals, representing 5 species, as well as mitochondrial 12S rDNA, nuclear 18S rDNA, and nuclear 28S rDNA for a select subset of these. Our COI dataset was leveraged to detect potential cryptic species, and to calculate genetic distances as a proxy for the degree of gene flow between populations. Augmented by numerous sequences from GenBank, the multilocus dataset was used to reconstruct a phylogenetic hypothesis for worldwide members of the genus. Beyond corroborating previous overarching phylogenetic frameworks, our results show that an undescribed species that is morphologically and genetically similar to Erpobdella punctata exists in sympatry with this species – the new species has likely been overlooked in previous studies due to its morphological similarity with Erpobdella punctata. Erpobdella bucera is reported from Canada for the first time; and Erpobdella microstoma is newly reported from Saskatchewan and placed in a phylogeny for the first time. Finally, we find evidence for genetic structure in both E. cf. punctata and Erpobdella obscura that is correlated with major river drainage basin boundaries in North America.

Ecological and faunistic characteristics of the leech fauna in the Bukhtarma Reservoir, Eastern Kazakhstan

The taxonomic diversity of the Hirudinea fauna and its dependence on the ecological conditions in the Bukhtarma Reservoir (Eastern Kazakhstan) have been studied. The morphological analysis has shown that these leeches belong to two orders and three families: Rhynchobdellida (families Glossiphoniidae and Piscicolidae) and Arhynchobdellida (family Erpobdellidae). On the whole, eight leech species from five genera (Alboglossiphonia, Helobdella, Theromyzon, Piscicola, and Erpobdella) have been identified. Among them, there are three glossiphoniid species (A. heteroclite, H. stagnalis, and T. tessulatum), two species of piscicolids (Piscicola geometra and Piscicola sp.), and three species of predatory leeches (E. octoculata, E. vilnensis, and Erpobdella sp.). Possible effects of hydrochemical parameters of the aquatic environment on the species diversity have been analyzed. Correlation has been revealed between the abundance of species and the physical and chemical characteristics of the environment.

Genetic diversity of freshwater leeches in Lake Gusinoe (eastern Siberia, Russia).

The study of leeches from Lake Gusinoe and its adjacent area offered us the possibility to determine species diversity. As a result, an updated species list of the Gusinoe Hirudinea fauna (Annelida, Clitellata) has been compiled. There are two orders and three families of leeches in the Gusinoe area: order Rhynchobdellida (families Glossiphoniidae and Piscicolidae) and order Arhynchobdellida (family Erpobdellidae). In total, 6 leech species belonging to 6 genera have been identified. Of these, 3 taxa belonging to the family Glossiphoniidae (Alboglossiphonia heteroclita f. papillosa, Hemiclepsis marginata, and Helobdella stagnalis) and representatives of 3 unidentified species (Glossiphonia sp., Piscicola sp., and Erpobdella sp.) have been recorded. The checklist gives a contemporary overview of the species composition of leeches and information on their hosts or substrates. The validity of morphological identification of each taxon has been verified by phylogenetic approach with a molecular marker adopted for a DNA barcoding of most invertebrates.

Erpobdellid leeches (Annelida, Clitellata, Hirudinida) from Tunisia: new records with the description of a new Trocheta species.

Up to now in Tunisia, freshwater Hirudinida are represented by two mainly haematophagous families: Hirudinidae and Glossiphonidae, and a predatory one: the family Erpobdellidae. The present study provides new information on the diversity and taxonomy of erpobdellid leeches. Identification was based, in addition to morphological data, on the length of sperm ducts and the lengths of ovisacs in relation to the neurosomite (ns) and on the shape and size of the male atrium. Five taxons are found. Two subspecies are reported for the first time in the country: Dina punctata punctata Johansson, 1927 and Dina punctata maroccana Nesemann and Neubert, 1994. Tunisian populations of two species, Erpobdella testacea (Savigny, 1820) and Trocheta africana Nesemann and Neubert, 1994, are described, with records of new localities. The new Trocheta tunisiana n. sp. is discovered and described in detail. Trocheta species live in springs in elevated areas while Erpobdella seem to prefer low altitude reservoirs. A comprehensive comparison of the three genera is presented. The disparity between the actual systematics and phylogeny is discussed. This study gives also a detailed distribution of the five species in the north of Tunisia with notes on ecological preference of the genus Dina. Finally a key for the determination of freshwater erpobdellid species from Tunisia is proposed.

The enduring toxicity of road-killed cane toads (Rhinella marina)

The primary ecological impact of invasive cane toads (Rhinella marina) in Australia is mediated by their powerful toxins, which are fatal to many native species. Toads use roads as invasion corridors and feeding sites, resulting in frequent road-kills. The flattened, desiccated toad carcasses remain highly toxic despite being heated daily to >40°C for many months during the tropical dry-season. In controlled laboratory experiments, native tadpoles (Cyclorana australis, Litoria rothii), fishes (Mogurnda mogurnda) and leeches (Family Erpobdellidae) died rapidly when we added fragments of sun-dried toad to their water, even if the native animals had no physical access to the carcass. Given the opportunity, native tadpoles and fishes strongly avoided the vicinity of dried toad fragments. Hence, long-dead toads may contaminate roadside ponds formed by early wet-season rains and induce avoidance and/or mortality of native anuran larvae, fishes and invertebrates. Our studies show that the toxicity of this invasive species does not end with the toad’s death, and that methods for disposing of toad carcasses (e.g., after culling operations) need to recognize the persistent danger posed by those carcasses.

Phylogenetic relationships in European erpobdellid leeches (Hirudinea: Erpobdellidae) inferred from restriction-site data of the 18S ribosomal gene and ITS2 region

The PCR-amplified 185 rRNA gene and ITS2 region were used for a restriction-site analysis to infer phylogenetic relationships among European representatives of the leech family Erpobdellidae and to test the phylogenetic reliability of the morphological characters used in this family till now. Fragment patterns produced by 11 restriction endonucleases in the 18S rRNA gene and by nine in the ITS2 region showed a higher interspecific variation in the latter than in the former genome component. No intraspecific variation could be detected, even among geographically very distant populations, except for the two supposed subspecies Trocheta b. bykowskii and T. b. krasense. The estimated overall nucleotide divergence (d) was lower in the genus Erpobdella (d = 0.015–0.061) than in the genera Dina and Trocheta (d = 0.049–0.090). E. testacea and E. monostriata do not seem to be as closely related to each other as previously thought; their pairwise nucleotide divergence (0.061) is highest within the genus Erpobdella. The nucleotide divergence between T. b. bykowskii and T. b. krasense (0.090), which greatly resemble each other morphologically, was surprisingly high. Phylogenetic trees were inferred via neighbour-joining and maximum parsimony methods. The trees support the monophyly of Erpobdellidae and the subdivision into two groups according to the pattern of annulation (the Erpobdella clade and the Dina-Trocheta clade). Further subdivision based on annulation patterns and other morphological characters is not supported. There was no molecular evidence for the monophyly of the genus Dina and the monophyly of the genus Trocheta.

Molecular phylogeny of selected predaceous leeches with reference to the evolution of body size and terrestrialism

The phylogenetic relationships of erpobdellid leeches collected throughout Europe were investigated using newly obtained mitochondrial cytochrome c oxidase subunit I (CO-I) gene sequence data from 10 taxa. Monophyly of the five European Erpobdella species (sub-family Erpobdellinae) was supported, but a newly discovered leech, E. wuttkei Kutschera, 2004 (the smallest member of its genus, discovered in an aquarium) was only distantly related to this clade. Three members of the semiaquatic Trochetinae were included in this study. The largest European leech species discovered so far, Trocheta haskonis Grosser, 2000, was found to be a terrestrial predator that feeds on earthworms. The rare species T. haskonis is the sister taxon of T. bykowskii Gedroyc, 1913, a well-known amphibious leech. Based on a comparison of body sizes and a phylogenetic tree the evolution of terrestrialism in the family Erpobdellidae is discussed.

Phylogeny of the leech family Erpobdellidae (Hirudinida : Oligochaeta)

The phylogenetic relationships of the family Erpobdellidae, a group of non-sanguivorous leeches useful as bioindicators, were investigated with the combined use of morphological characters, mitochondrial cytochrome c oxidase subunit I, mitochondrial 12S rDNA and nuclear 18S rDNA. Analyses of separate data sets and the combined data provide strong support for the contention that generic distinctions in the family are not reflective of phylogeny. The resulting hypothesis indicates the number of pairs of labial eyes as the sole morphological predictor of phylogenetic relationship. The traditionally used degree of annular subdivision is the least consistent character. In the absence of readily definable morphological synapomorphies for the resulting clades, the genera Dina, Mooreobdella, Nephelopsis and Trocheta are formally synonymised under the genus Erpobdella, the type genus of the family.

Higher Level Relationships of Leeches (Annelida: Clitellata: Euhirudinea) Based on Morphology and Gene Sequences

The evolutionary patterns of divergence of seven euhirudinean families were investigated by cladistic analysis of 33 euhirudinean species. Oligochaetes, Acanthobdella peledina, and branchiobdellidans were included as outgroup taxa. Cladistic analysis employed 1.8 kb of nuclear 18S ribosomal DNA and 651 bp of mitochondrial cytochrome c oxidase subunit I in addition to morphological data. The use of two molecular data sets, one nuclear gene and one mitochondrial gene, as well as morphological data combined historical information evolving under a variety of different constraints and therefore was less susceptible to the biases that could confound the use of only one type of data. Results suggest that the nuclear 18S rDNA gene yields a meaningful historical signal for determining higher level relationships. The more rapidly evolving CO-I gene was informative for recent or local areas of the evolutionary hypothesis, such as within-family relationships. Analyses combining all data from the three character sets yielded one most-parsimonious tree. Most of the higher taxa in recent leech systematics were well corroborated in the resulting topology. However, these results suggested paraphyly of the order Rhynchobdellida, which contradicts the presence of a proboscis as a synapomorphy. The medicinal leech family Hirudinidae was polyphyletic because Haemadipsidae and Haemopidae each have a hirudinid ancestor. In addition, all but one of the genera within the family Erpobdellidae must be either abandoned or renamed. Unusual findings included compelling evidence of historical plasticity in bloodfeeding behavior, having been lost at least four times in the course of euhirudinean evolution. Biogeographic patterns supported a New World origin for Arhynchobdellida.

A Circadian Rhythm of Swimming Behavior in a Predatory Leech of the Family Erpobdellidae

A wide variety of organisms exhibit circadian rhythms of motor behavior. These daily rhythms are advantageous because they allow animals to synchronize their activ- ities with predictable changes in the environment, including daily fluctuations of light, tem- perature and prey availability. With the exception of earthworms, however, research on cir- cadian rhythmicity in annelids is surprisingly limited (Brady, 1981). In this study, we used time-lapse video recordings to monitor the swimming activity patterns of Nephelopsis obscura, a freshwater predatory leech of the family Erpobdellidae. Leeches exposed to a LD 12:12 cycle swam significantly more at night than during the day (P < 0.001). Moreover, a circadian pattern of swimming behavior persisted for several days after leeches were placed in constant darkness (DD). We therefore conclude that leeches have a circadian clock influencing the expression of swimming behavior. To our knowledge, this is the first demonstration of an endogenous circadian rhythm of motor behavior in any leech species.

Is a visible clitellum an index of sexual maturity in erpobdellid leeches?

Summary Although it has been widely assumed that the presence of a visible clitellum closely parallels maturation of the female reproductive system in members of the family Erpobdellidae, this has never been thoroughly tested. Nephelopsis obscura was maintained at 15°C and 20°C and fed 3x, 2x or 1x a week with ad libitum prey. The leeches were examined weekly for the presence of a visible clitellum, spermatophores, the presence of vasa deferentia, and the stages of gametogenesis present determined. Feeding regime affected the time to the first occurrence of a visible clitellum with the leeches fed 3x a week exhibiting a clitellum 18–20 weeks before the first appearance of a clitellum in the groups fed 2x or lx a week at 15°C or 20°C. Regardless of feeding regime, all the leeches exhibited a second appearance of a clitellum after 41–48 weeks. The first appearance of a visible clitellum did not coincide with either spermatogenic or oogenic maturity, but at the second appearance of a clitellum leeches fed 3x...

A revision of the British leeches of the family Erpobdellidae, with a description of Dina lineata (O. F. Müller, 1774), a leech new to British fauna

Summary. Revised descriptions of the British leeches of the family Erpobdellidae are given, together with accounts of their principal variations. Since the British Erpobdellidae cannot with certainty be identified by examination of external characters, a technique is described for separating the genera and species by the shape of the genital atrium. The leech Dina lineata (O. F. Müller, 1774) is recorded in Britain for the first time. It was collected in a roadside pond rich in calcium and in organic matter. It is an isolated occurrence, probably an example of recent colonization. Erpobdella testacea cannot establish itself in an environment favourable to E. octoculata, but in conditions of sewage pollution, or low total alkalinity, E. testacea becomes dominant. The division of E. octoculata into var. vulgaris and var. atomaria is of no taxonomic significance, and should be discontinued. Trocheta subviridis has been found most frequently in London and the Home Counties, but also occurs in Manchester, Gloucester, Glamorgan and Oxford. It is frequently associated with sewage works.