Dorsal Pores Research Articles

A new pheretimoid earthworm of the genus Metaphire Sims & Easton, 1972 (Oligochaeta, Megascolecidae) from northeastern China with data from the mitochondrial genome

A new pheretimoid earthworm species, Metaphire liaoningensissp. nov., was investigated in northeastern China. The taxonomy of M. liaoningensissp. nov. using morphological characters and molecular data is reported, as well as its current geographical range in northeastern China. The new species, belonging to the M. houlleti species group, is characterized by having three pairs of spermathecal pores in 6/7/8/9, round and small pre-clitellar genital markings medio-ventral to the spermathecal pore opening, the first dorsal pore in 12/13, and the spermathecae ampulla large, nearly elliptical with a surface wrinkled and a duct long and stout. The molecular phylogenetic position of M. liaoningensissp. nov. within the M. houlleti species group is performed by COI and mitogenomic data, respectively. The COIK2P genetic distance between the new species and the other species within the M. houlleti species group was at least 16%. This is the second updated report of a new pheretimoid species in northeastern China since the last decade.

On three new species of the earthworm genus Drawida Michaelsen, 1900 (Clitellata: Moniligastridae) from south-western India.

Three new earthworm species of the genus Drawida Michaelsen, 1900, namely D. jatinderi Narayanan, sp. nov., D. paliwali Narayanan, sp. nov. and D. proboscidea Narayanan, sp. nov., are described from materials collected from the Kerala state of south-western India. D. jatinderi Narayanan, sp. nov., belongs to D. travancorensis Michaelsen, 1910 species group, characterized by spermathecal pores at C setal line, male pores at mid bc setal lines, glandular prostate, spermathecal atrium present, dorsal pores, and genital markings absent. Whereas D. paliwali Narayanan, sp. nov., and D. proboscidea Narayanan, sp. nov. belong to the D. robusta robusta (Bourne, 1886) group, characterized by glandular prostates and bilobed spermathecal atria. D. jatinderi Narayanan, sp. nov., and D. proboscidea Narayanan, sp. nov. were collected from the midlands of Ernakulam district, and D. paliwali Narayanan, sp. nov., was collected from the higher altitude evergreen forest of the Parambikulam Tiger Reserve of Palakkad district. Here we provide a detailed description of the external and internal characteristics of the new species, along with illustrations of the key characters. With the new findings, a total of 52 Drawida species are known from the Western Ghats biodiversity hotspot.

Larval development in the apodid sea cucumber Chiridota gigas, with a focus on coelom development and the serotonergic nervous system during metamorphosis

AbstractA unifying feature of echinoderm larvae is the development of a left anterior coelom, which consists of an undivided left axocoel and hydrocoel. Although the axocoel is a key deuterostome trait, the presence of this coelom in holothurians has been the subject of debate. Here, we focus on the development of the coelom in a basal holothuroid, the apodid Chiridota gigas (F. Chiridotidae). The dorsal pore and dorsal duct develop first, just after gastrulation, followed by expansion into an axohydrocoel in the auricularia. The left somatocoel was first evident adjacent to the stomach ~30 days post‐fertilization. The axohydrocoel differentiated into two distinct parts: the hydrocoel adjacent to the stomach, and a thin‐walled axocoel that was mid‐dorsal between the hydrocoel and the dorsal pore. This left axocoel extended to both the anterior and posterior but did not cross the larval midline. Out‐folding of the hydrocoel to form the primary tentacles was first observed at 58 days. Transition to a doliolaria with four‐rings was rapid (24 hr) and similar to the transition in other holothurians, with the hydrocoel encircling the esophagus. This transition involved a posterior shift of elements of the auricularia ciliary band and associated nervous system. The ciliary band of the auricularia was rearranged to form transverse bands of the doliolaria larva, and at the same time, the serotonergic cells and fibers that had been at the anterior end moved with the portions of the ciliary band with which they were associated. These serotonergic cells and fibers were still present in the pentactula. The first pentactula was observed at 66 days. Coelom development in C. gigas showed two differences from that in other holothurians, including the development of the left axocoel and the extension of the anterior coelom into the preoral lobe. Description of the full larval development in C. gigas also revealed highly variable morphology in the late auricularia stage, which may aid in identifying apodid holothurians from plankton samples.

A new species of Scapholeberis Schoedler, 1858 (Anomopoda: Daphniidae: Scapholeberinae) from the Colombian Amazon basin highlighted by DNA barcodes and morphology.

BackgroundThe Amazon basin is recognized as one of the most complex and species-rich freshwater environments globally. The diversity of zooplankton here remains unknown, with many species undescribed.MethodsHere, we describe a new species of Scapholeberis Schoedler, 1858 (Cladocera: Anomopoda: Daphniidae: Scapholeberinae) from the Colombian Amazon Basin, collected with recently designed light traps. The description is based on detailed morphology (based on SEM and light microscopy) of parthenogenetic females, ephippial females, males, and molecular data based on the COI gene.ResultsScapholeberis yahuarcaquensis n. sp. has a combination of characters present in Scapholeberis kingi Sars, 1888 and Scapholeberis armata freyi Dumont & Pensaert, 1983. These are a trilobate rostrum, with the middle lobe well developed with sides straight to relatively rounded, the presence of an elongated slit frontal head pore, a dorsal pore in the juncture of the cephalic shield and the valves, and a single denticulate membrane at the posterior rim of the valves, with stronger setae in the last third. The unique characters of the parthenogenetic females are ventral sucker with delicate triangles. Each has a filament-like projection in the lamellae’s inner side and an external section forming convex folds with denticle-like projections in the middle zone of the sucker-plate. There is a peculiar pitted sculpture in the ephippial females and a strong projection in the front of it. The male hook on the limb I with a blunt tip, a quirky lamella-like outgrow in the proximal side, and a paddle with well-developed spines scattered on its surface. The ventral sucker-lamellae in the male is much more developed than the female. The COI gene sequences showed an interspecific mean genetic divergence of 16.4% between S. yahuarcaquensis n. sp. and the closest species S. freyi from Mexico, supporting our results. A coalescence analysis and Barcode Index Number also support the new species based on the DNA sequences. New methods of collecting and integrative biology will give important support to recognize the fauna from the Amazon Basin, one of the most important sources of fresh water in the world that remains unknown in many respects.

Influence of Bionic Pit Structure on Friction and Sealing Performance of Reciprocating Plunger

A new kind of pit‐shaped bionic plunger proposes to reduce the frictional resistance of the reciprocating plunger and improve its sealing performance. According to the dorsal pore of earthworm, the bionic pit structure with different parameters designed and processed. The friction resistance test, observation test, and finite element analysis carried out. The results show that the bionic pit structure can improve the lubrication condition of the plunger surface and reduce the frictional resistance with a maximum drag reduction rate of 14.32%. The pit‐shaped bionic structure can increase the storage of lubricating oil, intercept the surface streamline, and decrease the flow rate. The bionic plungers’ mean contact pressure and oil film pressure increased significantly.

Research on the influence of elbow erosion characteristics based on bionic earthworm dorsal pore jet.

Based on the biological characteristics of earthworm, the dorsal pore jet parameters were analyzed to establish elbow erosion model. The discrete phase model and standard k-ε turbulence model were used to carry on numerical simulation of the erosion characteristics and study the mechanism of improving elbow erosion characteristics. The results showed that the most serious erosion area was the elbow lower surface, while bionic earthworm dorsal pore jet could significantly reduce the erosion rate of this area, thereby reducing the overall erosion rate. When the jet velocity was the same, the smaller the jet distance, the lower the erosion rate would be. With the increase of the jet velocity, the erosion rate decreased first and then increased. When the jet distance was 0.5 times the elbow diameter and the jet velocity was 0.3 times the flow velocity, the erosion rate was the lowest (decreased by 79.29%). When the jet velocity was less than 0.5 m·s-1, low-velocity strips formed at elbow lower surface due to the jet and reduced the kinetic energy of the solid particles near the wall; when the jet velocity was greater than 0.2 times the flow velocity, vortex cushion effect formed, therefore reduced the erosion rate significantly.

Characterization of the Chloroplast Genome of Trentepohlia odorata (Trentepohliales, Chlorophyta), and Discussion of its Taxonomy.

Trentepohliales is an aerial order of Chlorophyta with approximately 80 species distributed mainly in tropical and subtropical regions. The taxonomy of this genus is quite difficult and presents a challenge for many phycologists. Although plentiful molecular data is available, most of the sequences are not identified at the species level. In the present study, we described a new specimen with detailed morphological data and identified it as Trentepohlia odorata. A phylogenetic analysis showed T. odorata as a novel lineage in Trentepohliales. T. odorata has the closest relationship with T. annulata, which is expected since sporangia of both species are without stalk cell and with dorsal pore. Species with such morphological characteristics may represent deep lineages in Trentepohliales. Although an increasing number of chloroplast genomes of Ulvophyceae have been reported in recent years, the whole plastome of Trentepohliales has not yet been reported. Thus, the chloroplast genome of Trentepohlia odorata was reported in the present study. The whole plastome was 399,372 bp in length, with 63 predicted protein-coding genes, 31 tRNAs, and 3 rRNAs. Additionally, we annotated 95 free-standing open reading frames, of which seven were annotated with plastid origins, 16 with eukaryotic genome origins, and 33 with bacterial genome origins. Four rpo genes (rpoA, rpoB, rpoC1, and rpoC2) were annotated within ORF clusters. These four genes were fragmented into several (partial) ORFs by in-frame stop codons. Additionally, we detected a frame shift mutation in the rpoB gene. The phylogenetic analysis supported that Trentepohliales clustered with Dasycladales and nested into the BDT clade (Bryopsidales, Dasycladales and Trentepohliales). Our results present the first whole chloroplast genome of a species of Trentepohliales and provided new data for understanding the evolution of the chloroplast genome in Ulvophyceae.

New earthworm species of Amynthas (Clitellata: Megascolecidae) from Nam Phouin National Protected Area, Laos

Three new species of the earthworm genus Amynthas Kinberg, 1867 are described from Nam Phouin, Xayabouli Province, Laos. Amynthas appelhofae sp. nov. has spermathecal pores paired in 7/8/9 at 7th setal lines 0.22–0.29 circumference apart ventrally, simple intestinal caeca, and first dorsal pores in 4/5. Amynthas feakinsi sp. nov. has spermathecal pores paired in 5/6/7 at 17th setal lines, 0.30–0.35 circumference apart ventrally, manicate intestinal caeca, and first dorsal pores in 12/13. Amynthas nathanohlfsi sp. nov. has spermathecal pores paired in 6/7–8/9 at 2nd setal lines, 0.02–0.04 circumference apart ventrally, a single broad oval male porophore, and hearts only in segments XII and XIII.

Nine new species of the "aeruginosus"-group in Amynthas (Clitellata: Megascolecidae) from Nam Et-Phouley National protected Area, Laos.

Nine new species of Amynthas (Clitellata: Megascolecidae) from Mt. Phouleoi, Lao PDR: Earthworm specimens were collected on the top of Mt. Phouleoi, Viengthong District, Houaphanh province, Lao PDR. The new species belonged to pheretimoid earthworms. They have spermathecal pores in 7/8 and 8/9, corresponding to the aeruginosus-group as characterized by Sims and Easton (1972). Their names are: Amynthas bouatongi sp. nov., Amynthas hoauykanangensis sp. nov., Amynthas phimpheti sp. nov., Amynthas nametensis sp. nov., Amynthas somechanae sp. nov., Amynthas wiggeri sp. nov., Amynthas fleischmani sp. nov., Amynthas antethecus sp. nov., and Amynthas elenabondae sp. nov. With the exception of A. nametensis sp. nov., all have the first dorsal pore in an unusually anterior location close to 5/6 and very large, often coiled, prostatic ducts. Several species have slight intraparietal invaginations of the primary male pores, but the similarity of other characters leads us to include them in Amynthas rather than in a polyphyletic Metaphire. Amynthas bouatongi sp. nov. has male pores 0.20-0.24 circumference apart on reniform male pads, pair genital papillae medial and lateral to male pores in XVIII. Amynthas hoauykanangensis sp. nov. has openings of copulatory pouches 0.19-0.25 circumference apart, and paired round genital papillae on postsetal XVII and presetal XIX in line with the male pores. Amynthas phimpheti sp. nov. has male pores 0.21-0.24 circumference apart, round thickened genital papillae paired on 17/18 and 18/19 in line with male pores. Amynthas nametensis sp. nov. has male pores superficial on thickened circular pads, 0.24-0.27 circumference apart. Amynthas somechanae sp. nov. has male pores 0.20-0.33 circumference apart, and paired equatorial papillae in XVIII. Amynthas wiggeri sp. nov. has male pores 0.22-0.30 circumference apart, paired genital papillae equatorial on XVIII medial to male pores and paired papillae equatorial in XVII and XIX. Amynthas fleischmani sp. nov. has openings of copulatory pouches 0.24 circumference apart, paired conical genital papillae equatorial on XVII and XIX; paired circular papillae in intersegmental furrows of 17/18 and 18/19. Amynthas antethecus sp. nov. has openings of copulatory pouches 0.31 circumference apart, paired circular papillae in intersegmental furrow of 17/18 and equatorial on XIX, slightly medial to secondary male pores. Amynthas elenabondae sp. nov. has openings of copulatory pouches 0.19 circumference apart, crescent, convex medially; primary male pore on tubercle on lateral wall of shallow parietal invagination.

PROBLEMS SOLUTION OF SPECIAL IDENTIFICATION OF EISENIA CULTURAL POPULATIONS

PROBLEMS SOLUTION OF SPECIAL IDENTIFICATION OF EISENIA CULTURAL POPULATIONS

Nuevas lombrices de tierra acanthodrilidas de los géneros protozapotecia y trigaster de Cuba (annelida, crassiclitellata)

Se describen cuatro nuevas especies de la familia Acanthodrilidae del oeste (Protozapotecia angelesae sp.nov.), centro (Protozapotecia centralis sp.nov., Protozapotecia cubensis sp.nov.) y este de Cuba (Trigaster setarmata sp.nov.). Las nuevas especies están cercanamente relacionadas con la fauna del noreste y este de México (gé- neros Protozapotecia y Zapatadrilus) y de Puerto Rico e islas Vírgenes (Trigaster). Las nuevas especies de Protozapotecia se caracterizan por tener dos mollejas y holonefridios, mientras que la especie nueva de Trigaster presenta tres mollejas y meronefridios. Protozapotecia angelesae sp.nov. se separa de las especies mexicanas del género por carecer de tiflosol y quetas peneales y por presentar láminas esofágicas libres en los segmentos 11 y 12. Por la presencia de quetas peneales y tiflosol, las otras dos especies nuevas de Protozapotecia se acercan más a la fauna mexicana; mientras que Protozapotecia centralis sp.nov. se separa de todas ellas por el poro dorsal anterior en 4/5, las láminas esofágicas libres en el segmento 13 y el divertículo espermatecal lateral sésil, Protozapotecia cubensis sp.nov. se diferencia por los últimos corazones en el segmento 13 y por las láminas esofágicas libres en los segmentos 13,14 y 15. Trigaster setarmata sp.nov. se separa de las cuatro especies conocidas del género por presentar quetas peneales y próstatas racemosas. Clarificar el origen de la fauna de acanthodrilidos cubanos (dispersión o vicarianza) dependerá de futuras colectas y de contar con filogenias moleculares robustas

The genus Aitchisoniella Kashyap (Marchantiopsida, Cleveaceae) new to China, and its taxonomic placement

The genus Aitchisoniella with a single species A. himalayensis (Marchantiopsida, Cleveaceae), previously considered endemic to the north-west Himalayas of India, is reported for the first time from Sichuan Province, China. The genus is distinctive amongst complex thalloid liverworts in lacking stalked carpocephala but having archegonia and sporophytes borne on the ventral side of a short receptacle arising in a terminal thallus bifurcation. The receptacle tissue is continuous with that of the main thallus, with dorsal air chambers and air pores, and a ventral groove containing pegged rhizoids. Both molecular data and morphological characters, particularly spore ornamentation, suggest that its previous placement in Exormothecaceae is incorrect and it is now transferred to Cleveaceae, wherein it becomes the fifth genus. Revised descriptions of the families Cleveaceae and Corsiniaceae (including Exormothecaceae) are provided.

A new species of Cyrtodactylus (Squamata: Gekkonidae) from the limestone forest of Khammouane Province, central Laos.

We describe a new species of the genus Cyrtodactylus on the basis of three specimens from Khammouane Province, Laos. Cyrtodactylus soudthichaki sp. nov. is distinguished from the remaining congeners by the combination of the following characters: adult SVL 69.2-70.0 mm; dorsal head and neck with dark blotches; nuchal loop present; dorsum with five brown bands between limb insertions; 19 or 20 irregular rows of dorsal tubercles; 32 or 33 ventral scale rows; ventrolateral folds present, with distinct tubercles; dorsal surface of hind limbs with tubercles; 29 precloacal and femoral pores in a continuous row in males, precloacal pores absent in the female; enlarged femoral and precloacal scales present; 4 or 5 postcloacal tubercles; and subcaudals transversely enlarged. The new species most closely resembles Cyrtodactylus jaegeri and Cyrtodactylus roesleri in overall coloration and pattern. However, they can be clearly distinguished from each other in the number of dorsal tubercle rows, ventral scales, and femoral and precloacal pores. Cyrtodactylus soudthichaki is the 16th species of Cyrtodactylus known from Laos.

A Review of Bionic Technology for Drag Reduction Based on Analysis of Abilities the Earthworm

The earthworm is a common terrestrial animal, its physical structure and morphology characteristics are very distinctive. Through of imitation of the special abilities of earthworms, people can get the material to research on bionic technology, such as the jet, non-smooth surface, etc. It can provide the new design ideas for engineering technology. The study of earthworm body structure and its movement mechanism, can help people to find the drag reduction method in the process of movement. In addition, the earthworm non-smooth body surface, dorsal pore jet, surface lubrication, electroosmosis and its unique moving way form a good drag reduction effect. Therefore, research on earthworm is instructive for the development of bionic technology.

Restoration of experimentally depleted coelomocytes in juvenile and adult composting earthworms Eisenia andreiE. fetida and Dendrobaena veneta

Earthworms irritated by various noxious stimuli expel coelomic fluid through dorsal pores in the body wall. Coelomic fluid contains coelomocytes (amoebocytes and riboflavin-storing eleocytes) and soluble factors responsible for immune functions, thus efficient restoration of the depleted coelomocyte system has an important adaptive value for soil-dwelling species. The aim of present experiments was to compare restoration of coelomocytes and riboflavin (vitamin B2) after experimental expulsion performed in composting earthworms reared for generations in the same laboratory conditions. Dendrobaena veneta, Eisenia andrei and Eisenia fetida were identified according to morphological criteria, species-specific fluorophores, and DNA sequences of mitochondrial COI genes. Analyses (cell counting, flow cytometry, spectrofluorimetry) were conducted on juveniles and adults at the time of electric shock-induced depletion of coelomocyte-containing coelomic fluid and then three weeks later in worms recovering their immune systems, and in their untreated counterparts. Electric shock induced expulsion of approximately 90% amoebocytes, eleocytes, and riboflavin, followed by their gradual restoration that was still in progress 3 weeks later. Amoebocytes were restored faster than riboflavin and eleocytes. Riboflavin content was higher in restored than senescent eleocytes of adult worms. Process of restoration was faster in juveniles than in adults and in the former was connected with accelerated gain in body mass. Senescent coelomocytes of adult earthworms easily undergo fragmentation, while it was seldom observed in coelomocytes of juveniles and in newly formed coelomocytes replacing expelled cells in both adult and juvenile worms. Molecular basis of these phenomena are worth further elucidation.

Description and phylogenetic position of Amphora aliformis (Bacillariophyta), a new species from Tokyo Bay

:The genus Amphora is a large and widely distributed group of raphid diatoms, frequently found in fresh, brackish, and salt water environments from around the world. Presented here is the description and phylogenetic position of Amphora aliformis, a new species collected from the Banzu Flats, Tokyo Bay, Japan. This species has a unique morphology, with features seldom or never before observed within the genus Amphora, such as a dorsal marginal wing and ventral apical pores, as well as a unique phylogenetic position as an early diverging lineage within the genus. As with many large and diverse groups of diatoms, new evidence has called into question the validity of the long standing classification system for the genus Amphora. Within the previous system, A. aliformis would be prescribed to the subgenus Diplamphora based on morphological valve features. However, molecular phylogenetic analysis demonstrates that Diplamphora is not monophyletic and furthers evidence that Amphora classification is in need of revision. Included here is a description of A. aliformis based on light microscope, scanning electron microscope, and molecular phylogenetic data, as well as a re-examination and discussion of the current state of Amphora classification.

On Schmarda's lost earthworm and some newly found New Zealand species (Oligochaeta: Megadrilacea: Lumbricidae, Acanthodrilidae, Octochaetidae, & Megascolecidae s. stricto)

The saga of Megascolides orthostichon (Schmarda, 1861)-the first native worm described from Australasia-continues as its type-locality is unequivocally returned from Hobart, Tasmania to Mt Wellington, Auckland where a brief survey failed to unearth it. Since it has not been seen for 150 yrs, it may qualify under NZTCS or IUCN classification as 'Nationally Critical' if not 'Extinct'. New reports are for exotic Megascolecidae Anisochaeta kiwi sp. nov. and A. kiwi mihi sub-sp. nov. plus addition to the NZ faunal list of Australian Anisochaeta macleayi (Fletcher, 1889) that, due to its wide distribution in Australia and now New Zealand, may be a candidate model-species suitably resilient for eco-toxicological culture and monitoring. For holarctic Lumbricidae, new records are of Dendrobaena attemsi (Michaelsen, 1903) and the Murchieona muldali (Omodeo, 1956) morph or subspecies of M. minuscula (Rosa, 1906), neither lumbricid previously uncovered in Asia/Australasia. Also found for the first time outside its East Asian homeland is Eisenia japonica (Michaelsen, 1892) (which is compared to Japanese E. japonica hiramoto sub-sp. nov. and to E. anzac Blakemore, 2011). Records of these exotics plus recent new native species described by the author-including two, Rhododrilus mangamingi and Deinodrilus orcus spp. novae, herein-raise the numbers of megadriles known from New Zealand to 228 (sub-)species in five families. Preliminary mtDNA COI sequence barcodes are presented. Genus Tokea Benham, 1904 is revived on its lack of dorsal pores, losing or gaining some species with Megascolides M'Coy, 1878. An updated checklist of all 228 New Zealand taxa is appended.

Descriptions of two new species of earthworm of the genus Pheretima Kinberg, 1867 (Oligochaeta: Megascolecidae) from Mekong delta - Vietnam

In this article describes two new species of earthworm (Pheretima mangophila Nguyen, sp. n. and Pheretima thaii Nguyen, sp. n.) are found in Mekong delta - Vietnam. Pheretima mangophila Nguyen, sp. n. (figure 2): First dorsal pore in 12/13. Spermathecal pores two pairs in 5/6/7. Genital papillae absent. Septa 5/6 - 7/8 thickish, 8/9 and 9/10 absent, 10/11 - 12/13 thin. Intestinal caeca, manicate. Integumentary micronephridia in front of clitellum drop of water- shaped. Pheretima thaii Nguyen, sp. n. (figure 3): First dorsal pore in 12/13. Spermathecal pores three pairs in 5/6/7/8. Genital papillae absent. Septa 5/6/7thickish, 8/9 and 9/10 absent, 7/8 and 10/11/12 thin. Intestinal caeca, manicate.

Morphological Characters and Histology of Pheretima darnleiensis

Pheretima darnleiensis is a native earthworm of Southeast Asia, India, and Japan. Although it is commonly found in Indonesia, the earthworm has never been studied well. This study was aimed to examine the morphological characters and structure of its several organs for an identification purpose, which is important for the earthworm culture. Earthworms were collected in a plot of 55-150 x 55-150 cm width and 20 cm depth at Bogor Agricultural University in Darmaga and Baranangsiang Campuses by hand sorting method. Examinations were carried out on its external as well as internal characters. The histology of the organs was studied using paraffin method. The observed characters on P. darnleiensis were the presence of prostate gland, one pair of male pores on segment XVIII, a cylindrical body with perichaetine setae, caeca on segment XXVII, copulatory pouches without diverticula and stalked glands, bithecal spermatheca with nephridia, and the first spermathecal pore on segment 4/5. In addition, other characters found on P. darnleiensis were the presence of an annular clitellum on segment XIV-XVI, an epilobus prostomium with open base, approximately 40 single pointed setae on segment XIII, one midventral female pore on segment XIV, one pair of lateroventral male pores on segment XVIII, four pairs of lateroventral spermathecal pores on segment 4/5, 5/6, 6/7, 7/8, and the first middorsal dorsal pore on segment 12/13. The histology of P. darnleiensis showed basic structure as found in other earthworms.

Morphological investigations of microdrile oligochaetes (Annelida, Clitellata) using scanning electron microscopy

Over the past several years, the authors of this work have investigated external structures of microdrile oligochaetes using scanning electron microscopy (SEM). Both published and still-unpublished data have revealed new structures of interest, especially those associated with mating, ciliate sense receptors, chaetae, and dorsal pores. Mating systems can be classified in 3 categories: grasping, coupling, and embracing. Ciliate sense receptors can be classified as poorly defined (unelevated), sensory buds, or papillae, and are provided with blunt cilia and/or sharp cilia. They are present along the whole body (including clitellum, budding, and regeneration zones), scattered on the prostomium, peristomium, and pygidium, arranged in transversal rows and scattered in chaetal segments. Somatic chaetae show great variability when observed by SEM. Hair chaetae are at least potentially provided with denticulations. Dorsal pores were observed in aquatic microdriles. SEM proves to be an invaluable tool to discover important structures associated with functional anatomy in microdriles.