Zoology in the Middle East
Supplementum 2, 2010
Advances in Earthworm Taxonomy
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Price per article: Euro 10.00 (plus Euro 2.00 postage/handling)
Robert J. Blakemore
Saga of Herr Hilgendorf’s worms… (Oligochaeta, Megascolecidae)
Abstract. Herr Dr. Franz Hilgendorf, who first introduced Darwin’s evolutionary theory to Tokyo in 1873, collected ‘Vermes’ for Dr. Wilhelm Michaelsen in Hamburg. The Metaphire hilgendorfi (Michaelsen, 1892)/Amynthas tokioensis (Beddard, 1892) parthenogenetic/clonal spp-complex has since snowballed into >60 names, and its resolution remains the hottest yet seemingly intractable problem in Oriental (and Cosmopolitan) earthworm systematics. Reproductive structures, morphometrics, colouration or intestinal caeca characterizations are largely defunct. Molecular ‘solutions’ are meaningless without DNA analysis of types under the strict ICZN Principle of Typification in chronological order under its Principle of Priority. A revised diagnosis now accepts Metaphire spp from morphs having non-superficial male pores. Both Amynthas tokioensis (syns. ?M. levis; ?A. paiki syns. nov.) as a new record from USA and A. agrestis (Goto & Hatai, 1899) (syn. ?A. minjae Hong in Hong, Lee & Kim, 2001 syn. nov.) from Japan/Korea are reviewed. Metaphire soulensis (Kobayashi, 1938) and ?M. koellikeri (Michaelsen, 1928) are restored separately but the dubious A. defectus (Gates, 1930) (syn. A. jacita) is newly added to the group. Work is urgently needed to separate Metaphire Sims & Easton, 1972 from Amynthas Kinberg, 1867 and to sort degraded morphs under their respective types. More than a generation ago, Gates (1972) said naming intermediates is “ridiculous”. Despite this, names continue to be added by workers in Japan or Korea who mutually ignore earlier work in either country: Dozens of ‘nationalistic’ Japanese ‘Pheretima’ synonyms have been added as have Korean taxa with manicate caeca e.g., A. yongshilensis, A. alveolatus, A. geomunensis, A. eastoni, A. boletiformis, A. odaesanensis, A. righii, A. fasciiformis, A. sanchongensis, A. songnisanensis, A. ephippiatus and A. multimaculatus. A degraded digestive ‘tube’ from Korea named as Amynthas dageletensis Hong & Kim, 2005, plus A. sonjaesiki Hong & James, 2009 (syns. novae of A. tokioensis), have the lowest priority within this 118-year-old saga. Critical conditions of the intestinal caeca are briefly considered, and the emerging 117-year-old synonymy saga of Pheretima urceolata (Horst, 1893) is flagged as a new taxonomic ‘housekeeping’ concern. For all these issues, molecular resolution via DNA anaylsis of types is advocated.
Key words. earthworm eco-taxonomy, cosmopolitan species, pheretimoids, parthenogenesis, Oriental misdiagnosed megadriles.
Gergely Boros, Gabor Cech, Eszter Ari, Klara Dozsa-Farkas
Extension of employing ITS region in the investigation of Hungarian Fridericia species (Oligochaeta: Enchytraeidae)
Abstract. Same species of genus Fridericia (Oligochaeta: Enchytraeidae) collected from different localities, can have small differences in their morphology, for example, the number of nephridia or length and width of the spermathecal ectal duct. During the identification of enchytraeid worms, several characteristics were investigated at the same time but presence of small variations in only one or two main characteristics can cause taxonomic difficulties or may raise the possibility of encountering a subspecies. Using molecular biological techniques can help answer these questions. In preceding researches of the authors ITS (Internal Transcribed Spacer) came into focus. ITS is mainly a non-coding region of ribosomal DNA located between the 18S and 28S rDNA genes. Based on these previous studies, in the present analysis, the authors extended their investigation to include examination of the morphology and genes of various Fridericia species from different parts of Hungary. Phylogenetic trees were also created by Maximum Parsimony (MP), Neighbor-Joining (NJ), and Bayesian analyses. In the present study, we established that molecular biological techniques are suitable to confirm that individuals from the same species (but collected from different places) have the same genetic profile, while very similar species can be shown to clearly segregate on the phylogenetic tree based on the divergence of certain external or internal characteristics. Even though partial sequences give us only rough information about the phylogenetic position of the species, our aim is to show how the ITS region is suitable to investigate closely related enchytraeid worms and to differentiate the morphologically similar species.
Key words. ITS, Fridericia, Enchytraeidae, phylogeny.
Stephane Boyer, Stephen D. Wratten
Using molecular tools to identify New Zealand endemic earthworms in a mine restoration project (Oligochaeta: Acanthodrilidae, Lumbricidae, Megascolecidae)
Abstract. A restoration ecology project was commenced on the West Coast region of New Zealand to re-establish the local fauna of endemic Powelliphanta spp. carnivorous landsnails at an opencast coal mine site after mining activities. The aim of the current research is to provide recommendations for the use of earthworms to improve the restoration of ecological communities, especially the landsnails. To provide such recommendations, different aspects of the ecology and bio-systematics of the New Zealand endemic earthworm fauna have been studied using molecular techniques. About 1,500 earthworm individuals have been collected across 17 sampling sites in the Stockton mine area. In New Zealand, 173 endemic earthworm species are known. Only minor revisions to the earthworms’ taxonomic status have been made since 1959. Species identification was performed by morphological analysis (following Lee’s taxonomic key) and molecular analysis (using the mitochondrial 16S gene). The latter analyses conducted on a selection of 83 individuals revealed the existence of at least 17 different taxa, most of which are probably undescribed species. Some of these earthworm species are predated by an endangered carnivorous landsnail, Powelliphanta augusta Walker, Trewick & Barker. Because the conservation of P. augusta may rely greatly on the understanding of their diet, earthworm DNA was sought after in the snails’ feces, using molecular analyses. Molecular analyses have been helpful in establishing an inventory of the species present in the study site, facilitating new species taxonomic descriptions and elucidating the predator-prey relationship.
Key words. Earthworms, landsnails, New Zealand, restoration, mining, DNA.
Significance of using nephridia in the taxonomy of family Enchytraeidae (Annelida: Oligochaeta)
Abstract. A survey of the structure and variety of the nephridia in the subclass Oligochaeta is presented. The most diversified forms are discernible in the families of Megadrile earthworms Two main types can be differentiated: holonephridia and meronephridia. Both types can be exonephric when they penetrate the body-wall and open to the exterior. However, in the meronephridia, the ducts can open also into the intestine; in this case, it is called enteronephric. The nephridia in the family of Enchytraeidae are holo-exonephric; namely, they always have a ciliated funnel connected to a coiled duct much folded and embedded in a compact elongated body covered by a layer of peritoneum and through an efferent duct open to the exterior in the next segment. The shape of this organ, the structure and the ratio of pre- and post-septale parts, and the origin of the efferent duct can be generic or specific in character. The number of nephridia in preclitellar segments may contribute to identification of the species, but our knowledge on these characteristics is insufficient; therefore, it would be very useful to record these traits in all species descriptions.
Key words. Metanephridium, Oligochaeta, earthworm, Tubificidae, Enchytraeidae.
Jadwiga Danuta Plisko
Remarks on the South African endemic Proandricus lesothoensis species-group (Oligochaeta: Microchaetidae)
Abstract. Nine of fifty-three proandric South African endemic microchaetids, characterized by a location of spermathecae and their pores in testicular, and anterior to testicular segment, are discussed. Seven species: adami, amphius, bourquini, lesothoensis, oresbiosus, pajori and sani, with spermathecal pores in testicular and pre-testicular furrows, are accredited to the lesothoensis species-group. These species occur in only limited areas of the Central Drakensberg mountain range, and some of them display a discrepancy in the arrangement of setae. P. notabilis differing in size and shape of the body, possessing one pair of spermathecae in testicular segment 10 and other spermathecae in post-testicular segments in 11 and 12, with regular setal arrangement, is not included to this group. P. timmianus, in which pre-testicular spermathecae were noted only on histological slides, is also not included in the lesothoensis species-group, but was compared with other proandric species, e.g, biancae, briani and ianthinos, known from a neighboring area of timmianus type locality in the Eastern Cape. It is noteworthy that the presence of two rare characteristics, namely, location of spermathecae and their pores in segments anterior to testes, and irregularity in setal arrangements, are unique in South African microchaetid species and need more study.
Key words. Microchaetidae, Proandricus, lesothoensis species-group, South Africa.
Veronika S. Abukenova, Marat R. Khanturin
Adaptive features of life forms in Aporrectodea caliginosa (Oligochaeta: Lumbricidae)
Abstract. We considered that the morphoecological differences between species of Lumbricidae have adaptive character. For our research, the amplitude and frequency of contractions of the visceral (gizzard) smooth muscles were selected. The contractive activity of the muscles was studied according to the method of isolated preparations. The greatest amplitude of contractions (86.71±3.66 per mg) was recorded in worms of mineral soils for Aporrectodea caliginosa caliginosa in which the frequency of contractions of visceral muscles was 2.46±0.58 contr/min. Apparently, in detritophages the gut muscles push the dense food mass, but their contractions are not more frequent than 2-3 times a minute. The muscles of the surface-living A. caliginosa trapezoides showed smaller amplitude, 49.58±2.56 per mg, and frequencies were 4.89±0.37 contr/min. This subspecies ingested decaying vegetative remains, which entered their intestines as loose food mass completely accessible to digestion. Earthworms inhabiting mineral soil layers have greater amplitude of gut muscle contractions than the leaf-litter species, which is probably influenced by differences in their diet. We can conclude that parameters of spontaneous contractive activity of smooth muscles of the A. caliginosa digestive tract are related to the subspecies’ life characteristics in biocenosis. These parameters are stable characteristics of the forms adapted to consumption of certain types of food resources in natural habitats.
Key words. Earthworms, visceral muscles, contractive activity, gut, gizzard, isolated smooth muscles preparations.
Somayeh Ezzatpanah, Latif Robabeh, Malek Masoumeh, Salehi Hasan
Earthworm fauna of the western Mazandaran province, Iran (Oligochaeta: Lumbricidae, Megascolecidae)
Abstract. In the present study, earthworms were collected from the margins of rivers, forests, and wetlands of the Western Mazandaran province, Iran, from April 2007 to April 2008 at 18 designated stations. The following ten species were identified: Aporrectodea caliginosa, Ap. jassyensis, Dendrobaena byblica complex, D. hortensis, D. octaedra, D. veneta, Eisenia fetida, Eiseniella tetraedra, Perelia kaznakovi (all family Lumbricidae) and Amynthas corticis (family Megascolecidae). The Ei. tetraedra species comprises a new record for the studied region.
Key words: Earthworm, Lumbricidae, Megascolecidae, Mazandaran province, Iran.
Annely Kuu, Mari Ivask
Distribution of Octolasion cyaneum (Savigny, 1826) in Estonia 1993-2008 (Oligochaeta, Lumbricidae)
Abstract. The aim of the paper is to give an overview about distribution of the endogeic species Octalasion cyaneum (Savigny, 1826) in Estonia. First time, this endogeic species was found in 1980s in the Tallinn Botanical Garden (Northern-Estonia). The new results show that O. cyaneum is slowly expanding into Estonian territory and becoming more abundant.
Distribution of endemic earthworm species in Turkey (Oligochaeta: Lumbricidae)
Abstract. Seventy-five earthworm species have so far been found in Turkey. Out of them five species (7%) belong to families Criodrilidae, Megascolecidae and Acanthodrilidae, and 70 species (93%) are from the family Lumbricidae. Twenty-five lumbricid earthworms (33% of all species) are regarded as Anatolian endemics, i.e., endemics of the larger Asiatic part of Turkey. In contrast, no endemic species are known from the much smaller Thrace region (European part of Turkey). As expected, the endemism is not distributed evenly all over the territory; the level of endemic species richness is decreasing from the northern part of Anatolia (16 species, 64% from all endemics), through the Anatolian part of the Marmara region (9 species, 36%), Central Anatolia (4 species, 16%), the Mediterranean region (4 species, 16%), the Aegean region (3 species, 12%), and the eastern Anatolia regions (2 species each, 8% each) up to south-east Anatolia (no endemic species recorded). However, more detailed investigation is needed because large areas of Turkey have not yet been surveyed properly for earthworms.
Key words. Endemism, biodiversity, earthworms, Lumbricidae, Anatolia, Turkey.
Adriana Antonia Pop, Victor V. Pop, Csaba Csuzdi
Significance of the Apuseni Mountains (the Carpathians) in the origin and distribution of Central European earthworm fauna (Oligochaeta: Lumbricidae)
Abstract. The earthworm fauna of the Apuseni Mountains is very rich in species, most of them are narrowly distributed endemics. Till now 37 Lumbricidae taxa are known from the Apuseni Mts. of which 13 occur exclusively here. This high number of local endemism is in accordance with the tectonic history of the region. In the southern part, with patchily distributed limestone areas, an accelerated insular-like speciation resulted in presence of many endemic large-bodied Octodrilus species. In the northern volcanic region other endemics such as Dendrobaena sp. nov. and Allolobophora prosselodacica were found. These species show an allopatric distribution with their Carpathian vicariant sister species D. attemsi and A. sturanyi dacidoides respectively. The origin of such Apuseni–Carpathian species pairs is possibly due to the Parathethys transgressions which repeatedly isolated the Carpathians from the Apuseni Mts. in the Tertiary period for a long time. After the final retreat of the Parathetys from the Carpathian Basin some species with larger dispersion capabilities such as Dendrobaena clujensis, Allolobophora sturanyi dacica, Allolobophora mehadiensis etc. migrated to lower altitude hilly and plain habitats forming the so called Dacian faunal element in Central Europe. Our molecular phylogenetic investigations (16S and COI sequences) corroborate this scenario. The high number of endemic species, as well as their distribution patterns places the Apuseni Mts. as a hot-spot of lumbricid earthworms’ diversification and distribution in Central Europe.
Key words. Earthworms, Apuseni Mts., the Carpathians, evolution, rDNA, endemisms.
Naime Arslan, Arzu Çiçek, Cansev Akkan, Deniz Kilinç, Emrah Aci
Accumulation of heavy metals by earthworms in boron-contaminated area (Kırka-Eskişehir) (Oligochaeta: Lumbricidae)
Abstract. Boron is a naturally occurring material and is used in domestic and industrial products. Kırka region possesses the largest boron deposits not only in Turkey but also in the world. Even though boron is an essential nutrient for plants and an essential element for many organisms, certain concentrations can be toxic to aquatic and terrestrial organisms. This paper investigates the concentration of boron in soil and an earthworm (Eiseniella tetraedra) collected from five sampling sites at different times during the year 2008 from surrounding areas of the Kırka county of Eskişehir. Because the adsorption of borates into soils is controlled by the presence of aluminum and iron, earthworms and soil were also analyzed for aluminum and iron. Our results show that earthworm samples accumulated more boron than soil and at five sampling sites aluminum and iron were present in soil at relatively high concentrations.
Key words. Earthworms, accumulation, boron, Kırka.
Davorka Jaric, Branimir K. Hackenberger, Stjepan Krcmar
The characteristics of earthworm communities along vertically stratified transect of Velika Kapela Mountain grasslands (Croatia) (Oligochaeta: Lumbricidae)
Abstract. The spatial and temporal variability of earthworm populations is very high, both within and between differently managed types of land. Additionally, grassland ecosystem earthworm communities are reported as more heterogeneous and difficult to distinguish from one another in comparison to other types of ecosystems. The current study involves seven sites situated along the transect from the city of Ogulin on the continental slope to the Novi Vinodolski on the Mediterranean slope of the Velika Kapela Mountain. A plot of approximately 100 x 100 m in size was randomly selected for study. On each selected plot, seven random, seven transect, and 16 regular grid sampling points were chosen for earthworm sampling. A combination of hand sorting and expulsion by formalin was used for earthworm sampling. From all three sampling designs, transect had the lowest species number observed in all seven sites and regular grid sampling elicited the highest number of species in five sites. Two sites on the south-eastern slope of the Velika Kapela Mountain had the lowest species richness among all sites. The total number of species per site ranged from three to eleven. Aporrectodea rosea (Savigny, 1826) was the only species present at all seven sites, followed by Dendrobaena octaedra (Savigny, 1826) and Octolasion lacteum (Örley, 1881) found on five sites. The use of various species richness estimators suggested that on several sites one or two species were lacking from the sampling.
Key words. sampling design; regular grid; formalin expulsion; species richness estimators; juvenile/adult ratio
Cynthia Ramos, Monica Alfaro, Sonia Borges, Jose A. Amador
Earthworm taxonomic structure of coffee plantations at three soil associations in Puerto Rico (Oligochaeta: Glossoscolecidae, Megascolecidae)
Abstract. The taxonomic structure of earthworms of coffee plantations systems at three different places in Puerto Rico (Las Marías, Lares, and Jayuya), representing different soil types, was assessed. Organisms were manually sorted in a 0.25 m2, and various soil analyses were carried out. Eight earthworm species were identified: Onychochaeta borincana, Pontoscolex corethrurus, P. melissae, P. spiralis, and Pontoscolex sp., which belong to the Glossocolecidae family, and Amynthas gracilis, A. rodericensis, and a pheretimoid species which belong to the Megascolecidae family. Some significant differences among soil properties were found between locations, treatments, and the interaction effects, but no clear patterns between these differences accounted for the taxonomic structure and abundance of earthworms at these coffee plantations. Higher abundances of exotic species were found in the most distressed areas as expected. P. corethrurus was found at all the investigated coffee plantations. Lares, the second area of highest elevation, had the higher density of earthworms. On the other hand, Jayuya, the most isolated area, had the highest species number. P. melissae, a rare species that had been reported from only three locations in Puerto Rico when it was described in 1991, was found only in Jayuya.
Key words. Earthworms, coffee plantations, Puerto Rico.
Satyendra M. Singh, Om Prakash, Geeta R. Gangwar, Rachna
Species richness and density of earthworms in western Uttar Pradesh, India (Oligochaeta: Megascolecidae, Octochaetidae)
Abstract. The study was conducted in agricultural lands of five regions of western Uttar Pradesh, India, from 2006-2008 to identify species richness and density of earthworms in different seasons. Three species of earthworm’s viz., Metaphire posthuma (Vaill.), Lampito mauritii (Kinberg, 1867) and Perionyx excavatus (Perrier, 1872) from the Megascolecidae family and four species of Eutyphoeus waltoni (Michaelsen, 1907), E. gigas (Stephenson, 1917), E. orientalis (Beddard, 1883), and E. pharpingianus (Michaelsen, 1907) from Octochaetidae were identified and recorded. Bareilly of western Uttar Pradesh was identified as a density rich region of earthworms in all of the three seasons. It was species rich region of earthworms during winter and summer seasons too while the Agra region during the rainy season. Species richness and density of worms were assessed, the maximum in Bareilly and the minimum density in Saharanpur during peak winter months. However, the species richness of earthworms was found the least in three regions (Agra, Meerut, and Saharanpur) during winter months i.e. from November to February. In summers (March to June), both the density and species richness of earthworms were higher in Bareilly but their density was lower in Saharanpur. Interestingly, less species richness was noticed in Moradabad and Meerut regions with only three species. Results of taxonomic work indicated that the Bareilly region of western Uttar Pradesh has the maximum density of earthworms in all of the three seasons during the study; while the Agra region with more species richness during the rainy season. Variations in density and species richness of worms were discussed in the light of climatic conditions.
Key words. Earthworm, species richness, density, agricultural land, western Uttar Pradesh state.
Irina Victorovna Zenkova
Diversity of earthworms and ecology of the dominating species Lumbricus rubellus Hoffmeister, 1843 in the northern taiga podzols of the Murmansk region (Oligochaeta, Lumbricidae)
Abstract. Soil-zoological studies were carried out in ten old-growth forests of the northern taiga subzone of the Murmansk region and species composition, density, and the biomass of earthworms were assessed. Four species of earthworms were identified in pine and spruce forests, and among them dominant were the litter species Dendrobaena octaedra and the soil-litter species Lumbricus rubellus. It has been concluded that earthworm species composition, density, and biomass reach maximum values in forest litters characterized by increased ash content, reduced acidity, and containing organic matter of the humate type. Bioindicators of litters having such properties are L. rubellus and Aporrectodea caliginosa while the former is predominant. Body sizes and weight, seasonal and long-term dynamics of population are described for L. rubellus. Based on the peculiarities of intra-biotope distribution of earthworms, optima for main soil factors were determined.
Key words. Northern taiga podzols, pine, spruce, population, dynamics, spatial distribution, optima.
Seray Yildiz, M. Rusen Ustaoglu, Süleyman Balik
Littoral Oligochaeta (Lumbriculidae and Enchytraeidae) communities of some mountain lakes in the Eastern Black Sea Range (Turkey)
Abstract. Six surveys were carried out during July and August 2005–2007 in order to determine the Oligochaeta fauna of high-altitude lakes located in the Eastern Black Sea Range. With the highest peak, Kaçkar Dağı (elevation 3937 metres), and mountain plateaus at about 3000 metres in elevation, are the highest part of the Eastern Black Sea Range. This range is one of the most important glacial region in Turkey. Some physico-chemical features and Oligochaeta fauna of 39 lakes were determined for the first time, where no previous faunistic studies took place. As a result of the study, a total of 10 taxa was identified, comprising 3 species from Lumbriculidae [(Stylodrilus parvus (Hrabě & Černosvitov, 1927), Stylodrilus heringianus Claparede, 1862, and Lumbriculus variegatus (Müller, 1774)], 7 taxa from Enchytraeidae [(Cognettia sphagnetorum (Vejdovsky, 1878), Cognettia glandulosa (Michaelsen, 1889), Mesenchytraeus armatus (Levinsen, 1884), Mesenchytraeus sp., Henlea ventriculosa (d’Udekem, 1854), Henlea perpusilla Friend, 1911, and Henlea sp.)]. All the taxa represent new records for the region. Stylodrilus heringianus is recorded for the first time in Turkey.
Key words. Lumbriculidae, Enchytraeidae, littoral, Oligochaeta, fauna, Eastern Black Sea Range, Turkey
Veronika S. Abukenova
Earthworm fauna of Kazakh upland (Oligochaeta: Lumbricidae)
Abstract. The species composition of earthworms of different ecosystems in Kazakh upland (Kazakhstan) representing different soil types was assessed for the first time. This eco-region encompasses a large dry steppe area. It is considerably higher than the surrounding Western Siberian plains and Turgay plains. It features elevated plains, melkosopochniki (the local name for highly eroded plateaus), and low mountains. Habitat types characteristic to this area include petrophitic steppes with shrubs and brushwoods, granite rock pinewoods in the low mountains, and microphyllous woods associated with lakes and wetlands. Well represented intrazonal communities include wetlands and associated forests. Pine, birch, and aspen woods are found. Earthworms from Kazakh upland belong to seven genera, nine species, and three subspecies. These earthworms are widespread, a majority of which have an antropochoric dispersion however there are several native Asian species and subspecies as well. Development of a hydrological network promotes preservation of some forest species from the past, e.g., Dendrobaena octaedra and Eisenia nordenskioldi pallida. Moreover the boreal species of soil fauna specify the connection of area of research with the West-Siberian plain, Altai and southern Urals Mountains in the past. The epigeic D. octaedra and Dendrodrilus rubidus tenuis play a key role in the structure and function of the earthworm assemblages in the biotopes studied. The earthworm fauna is more diverse in forests of the northern and the southern parts of Kazakh upland than elsewhere in this arid zone of the country.
Key words. Dry steppe region, earthworms, epigeic and endogeic species, Kazakh Upland.
Earthworms in Traditional Chinese Medicine (Oligochaeta: Lumbricidae, Megascolecidae)
Abstract. The earthworm, 蚯蚓 (qiu yin) was first documented in the Divine Farmer’s Materia Medica Classic (神农本草经) around 200 B.C – 200 A.D. The 365 drugs in this book were classified into three groups: up, middle, and low. The 120 drugs in the up group are regarded as non-toxic and benefit qi (able to strength the vital body energy), so they can be taken regularly. The 120 drugs in the middle group are toxic or non-toxic, and used for treating diseases and supplementing deficiency. The drugs in the low group are toxic, and can eliminate “evil” (anything which causes illness) and should not be taken for a long period of time (Toxic implies the drug has strong medicinal effect and could have side effects so should be used properly and cautiously). The earthworm belongs to the low group. But in later medical literature, the earthworm is considered as non-toxic (Compendium of Materia Medica 本草纲目, 1552-1593).
Key words. Earthworms, traditional medicine, China.
Evangelia Vavoulidou, Loukia Dellaporta, Dimitris Joannis Bilalis
Collagen distribution in the tissue of the earthworm Octodrilus complanatus (Oligochaeta: Lumbricidae)
Abstract. Octodrilus complanatus (Lumbricidae) is a relatively large earthworm species widespread in the Hellenic territory and beyond. The main objective of our study was the histological description of O. complanatus and the determination of collagen distribution in its tissues. The histological study was carried out by means of hematoxylin-eosin staining in paraffin sections. The distribution of collagen was examined by histochemical techniques: CAB and Trichrom masson. The paraffin sections were examined by a light microscope after staining and the internal organs of the earthworm (alimentary canal, nervous, excretory, circulatory, and reproductive systems) were described. Most of the collagen was found in the cuticle, in the muscles under the epidermis and in the nervous system.
Key words. Lumbricidae, Octodrilus complanatus, collagen distribution, nervous system, digestive system.