Genomes were 'scrambled' when worms left the sea.

Chromosomal chaos may have aided their moves to fresh water and land.

Ovary micromorphology in hormogastrid earthworms with a particular emphasis on the organization of the germline cysts.

There is a gap in our knowledge of microorganization and the functioning of ovaries in earthworms (Crassiclitellata) and allied taxa. Recent analyses of ovaries in microdriles and leech-like taxa revealed that they are composed of syncytial germline cysts accompanied by somatic cells. Although the pattern of cyst organization is conserved across Clitellata - each cell is connected via one intercellular bridge (ring canal) to the central and anuclear cytoplasmic mass termed the cytophore - this system shows high evolutionary plasticity. In Crassiclitellata, only the gross morphology of ovaries and their segmental localization is well known, whereas ultrastructural data are limited to lumbricids like Dendrobaena veneta. Here we present the first report about ovarian histology and ultrastructure in Hormogastridae, a small family of earthworms inhabiting the western parts of the Mediterranean sea basin. We analyzed three species from three different genera and showed that the pattern of ovary organization is the same within this taxon. Ovaries are cone-like, with a broad part connected to the septum and a narrow distal end forming an egg string. Ovaries are composed of numerous cysts uniting a small number of cells, eight in Carpetania matritensis. There is a gradient of cysts development along the long ovary axis, and three zones can be distinguished. In zone I, cysts develop in complete synchrony and unite oogonia and early meiotic cells (till diplotene). Then (zone II), the synchrony is lost, and one cell (prospective oocyte) grows faster than the rest (prospective nurse cells). In zone III, oocytes pass the growth phase and gather nutrients; at this time, their contact with the cytophore is lost. Nurse cells grow slightly, eventually die via apoptosis, and are removed by coelomocytes. The most characteristic feature of hormogastrid germ cysts is the inconspicuous cytophore in the form of thread-like thin cytoplasmic strands (reticular cytophore). We found that the ovary organization in studied hormogastrids is very similar to that described for D. veneta and propose the term "Dendrobaena" type of ovaries. We expect the same microorganization of ovaries will be found in other hormogastrids and lumbricids.

Origin and diversification of pheretimoid megascolecid earthworms in the Japanese Archipelago as revealed by mitogenomic phylogenetics.

Megascolecid earthworms of the pheretimoid group are dominant detritivores of soil ecosystems in the Japanese Archipelago and East Asia. However, their diversity and phylogenetic relationships are poorly understood. We assembled whole mitogenome sequences for 197 megascolecid earthworms collected throughout Japan to study the phylogenetic relationships, phylogeography, divergence times, and diversification of important morphological characteristics among pheretimoid earthworms. Using 197 mitogenome sequences and 24 published mitogenome sequences from the East Asian mainland (221 sequences in total), we constructed a maximum likelihood tree and found that the pheretimoid earthworms currently assigned to Amynthas, Metaphire, Duplodicodrilus, and Manus are involved in the most senior genus Amynthas; thus, Amynthas can be treated as the sole genus encompassing all of the above genera. Within the Amynthas group, we identified three major lineages that led to four groups of endemic species in Japan. These lineages originated from different lineages on the East Asian mainland and Taiwan Island, indicating multiple colonization events from the East Asian mainland by different ancestral lineages, possibly after the Miocene. We also assembled nuclear ribosomal DNA sequences encompassing the 18S to 28S rRNA genes. The nuclear gene tree showed major groups consistent with the mitogenome tree except for different (and not well-resolved) relationships among major clades. Our molecular data covered 115-158 native and 7 non-native Amynthas group species in Japan in terms of DNA-based species delimitation. Our findings provide a basis for understanding the evolutionary relationships among diversified megascolecid earthworms in the Amynthas group in Japan and adjacent regions.

Four new enchytraeid species (Enchytraeidae, Annelida) from a Korean mountain (Jeoksangsan).

In this article, the descriptions of four new enchytraeid species (Enchytraeidae, Clitellata) from Jeoksangsan (Deogyusan National Park, Korea) are presented: Decimodrilus bulbosus sp. n., Fridericia jeoksangsaniensis sp. n., Fridericia sphaericoides sp. n. and Mesenchytraeus globiferus sp. n. Validity of these new species was verified by comparative morphological and molecular taxonomic analyses (based on the ITS region, CO1 and H3 genes). Apart from the new species, 13 other enchytraeid species were recorded in the soil samples of Jeoksangsan. In addition, new reference sequences are provided for the previously described Fridericia seoraksani Christensen Dzsa-Farkas, 2012.

DNA Barcoding: Molecular Identification and Phylogenetic Analysis of Pheretimoid Earthworm (Metaphire sp. and Amynthas sp.) Based on Mitochondrial Partial COI Gene from Sialkot, Pakistan.

The extremely difficult and challenging process is identifying pheretimoid species, genus Metaphire and Amynthas involving increased homoplasy in various morphological characteristics. The molecular identification, phylogenetic relationships, and evolutionary divergence time of earthworms belonging to the pheretimoid complex were investigated in this study using partial mitochondrial COI (cytochrome C oxidase subunit I) gene sequences ranging from 550-680 bp. Results revealed that 86 pheretimoid earthworms were morphologically different from a total of 342 mature worms. Moreover, 11 pheretimoid species were molecularly identified, including Metaphire posthuma (02), M. anomala (01), M. houlleti (02), M. californica (01), M. birmanica (02), Amynthas minimus (01), A. morrisi (01), and M. bununa (01). A phylogenetic tree was constructed with bootstrap values of 95%, which supported a monophyletic lineage of two well-supported clades formed by 12 partial COI sequences and 48 GenBank sequences using Hirudo medicinalis as an outgroup. The monophyly of these obtained genera indicated overall similarity at species level. Today, species like Amynthas, Metaphire and Pheretima have worm diversity in the form of pheretimoid earthworms, which dates to the Late Miocene (11.2-5.3 Mya) and the Pliocene (5.3-2.4 Mya). Compared to all relevant pheretimoid species, genetic p-distance values ranged from 0.0% to 0.57% (less than 1%). These low range values demonstrated that both genera Metaphire and Amynthas, supported the theory, which states that there are shared similarities among the species, despite different morphology. The current study is the first attempt in Pakistan to identify earthworms through DNA barcoding thus providing a genomic stamp. The work explored the significance of COI gene sequences to construct molecular tools that will be useful to overcome the different obstacles in morphologically similar earthworm identification and their phylogenetic study.

Macrofauna del suelo y condiciones edafoclimáticas en un gradiente altitudinal de zonas cafeteras, Huila, Colombia / Soil macrofauna and edaphoclimatic conditions in an altitude gradient of coffee growing regions, Huila, Colombia

Introducción: La macrofauna del suelo cumple un rol clave en los procesos del suelo, por lo tanto, regula la oferta se servicios ecosistémicos; sin embargo, su nivel de actividad depende en gran parte de las condiciones edafoclimáticas. Objetivo: El presente trabajo evaluó el efecto del gradiente de altitud sobre comunidades de macrofauna del suelo y propiedades edafoclimáticas en zonas cafeteras del Norte del Huila. Métodos: El estudio incluyó 12 lotes de café separados en dos gradientes de altitud: bajo (1 300-1 600 m.s.n.m) y alto (1 600-1 900 m.s.n.m), se recolectó la macrofauna del suelo mediante monolitos (25 x 25 cm a 30 cm de profundidad) y se estudiaron las condiciones edafoclimáticas. Resultados: En total se registró 9 520 individuos m-2 y una riqueza específica de 14 táxones. Las condiciones edafoclimáticas con mayor diferencia estadística entre los gradientes de altitud, fue la temperatura ambiente y humedad relativa con diferencias de 4.9 °C y 10.4 %, respectivamente. Conclusiones: La mayor abundancia de Coleoptera, Hemiptera, Isoptera y Lepidoptera se presentó en sitios más cálidos, es decir a un gradiente de altitud entre 1 300-1 600 m.s.n.m, mientras que Chilopoda y Diplopoda se adaptaron mejor a sitios más fríos en el gradiente altitudinal entre 1 600-1 900 m.s.n.m.

Introduction: Soil macrofauna plays a key role in soil processes and therefore regulates the supply of ecosystem services; however, its level of activity depends largely of the edaphoclimatic conditions. Objective: This work evaluated the effect of altitude gradient on soil macrofauna communities and edafoclimatic properties in coffee zones of North Huila. Methods: The study included 12 coffee lots separated in two altitude gradients: low (1 300-1 600 masl) and high (1 600-1 900 masl). Soil macrofauna was collected by means of monoliths (25 x 25 cm with 30 cm depth) and edaphoclimatic conditions were studied. Results: A total of 9 520 individuals m-2 and a specific richness of 14 taxa were registered. The edaphoclimatic conditions with the greatest statistical difference between altitude gradients were the environmental temperature and relative humidity with differences of 4.9 °C and 10.4 %, respectively. Conclusions: The highest abundance of Coleoptera, Hemiptera, Isoptera, Lepidoptera was presented in warmer sites, that is, altitude gradient 1 300-1 600 masl, while Chilopoda and Diplopoda adapted better to colder sites in altitude gradient 1 600-1 900 m.a.s.l.

Exploring new records of Eutyphoeus sp. (haplotaxida: Octochaetidae) from garo hills, Meghalaya, North Eastern state of India with use of DNA barcodes.

The work was aimed to investigate earthworms species particularly Eutyphoeus endemic to India with the use of DNA barcodes and usual morpho-anatomical standards of earthworm taxonomy from protected areas of Garo Hills, Meghalaya, the north-east region (NER) of India. The study revealed two new records Eutyphoeus kempi Stephenson, E. nepalensis Michaelsen and confirms availability of three known sp. namely E. callosus Gates, E. gammiei Beddard and E. turaensis Stephenson. The neighbor-joining tree was constructed using the K2P substitution model and the genomic signature of each species using COI-1 gene was generated for the first time and were used to reconfirm the identification of species.

Annelid Coelomic Fluid Proteins.

The coelomic cavity is part of the main body plan of annelids. This fluid filled space takes up a considerable volume of the body and serves as an important site of exchange of both metabolites and proteins. In addition to low molecular substances such as amino acids and glucose and lactate, the coelomic fluid contains different proteins that can arise through release from adjacent tissues (intestine) or from secretion by coelomic cells. In this chapter, we will review the current knowledge about the proteins in the annelid coelomic fluid. Given the number of more than 20,000 extant annelid species, existing studies are confined to a relatively few species. Most studies on the oligochaetes are confined to the earthworms-clearly because of their important role in soil biology. In the polychaetes (which might represent a paraphyletic group) on the other hand, studies have focused on a few species of the Nereidid family. The proteins present in the coelomic fluid serve different functions and these have been studied in different taxonomic groups. In oligochaetes, proteins involved antibacterial defense such as lysenin and fetidin have received much attention in past and ongoing studies. In polychaetes, in contrast, proteins involved in vitellogenesis and reproduction, and the vitellogenic function of coelomic cells have been investigated in more detail. The metal binding metallothioneins as well as antimicrobial peptides, have been investigated in both oligochaetes and polychaetes. In the light of the literature available, this review will focus on lipoproteins, especially vitellogenin, and proteins involved in defense reactions. Other annelid groups such as the Pogonophora, Echiura, and Sipuncula (now considered polychaetes), have not received much attention and therefore, this overview is far from being complete.

Untangling a mess of worms: Species delimitations reveal morphological crypsis and variability in Southeast Asian semi-aquatic earthworms (Almidae, Glyphidrilus).

Semi-aquatic freshwater earthworms in the genus Glyphidrilus from Southeast Asia are characterized by both an extreme morphological crypsis among divergent phylogenetic lineages and a high morphological variability within the same phylogenetic lineages. The present study provides a new taxonomic framework for this problematic genus in SE Asia by integrating DNA sequence and morphological data. When single-locus and multilocus multispecies coalescent-based (MSC) species delimitation methods were applied to DNA sequence data, they usually yielded highly incongruent results compared to morphology-based species identifications. This suggested the presence of several cryptic species and high levels of intraspecific morphological variation. Applying reciprocal monophyly to the cytochrome c oxidase subunit 1 (COI) gene tree allowed us to propose the existence of 33 monophyletic species. Yet, often substantially more molecular operational taxonomic units (MOTUs) were obtained when species delimitation was based on COI and 16S rRNA sequences. In contrast, the ITS1 and ITS2 sequences suggested fewer MOTUs and did not recover most of the monophyletic species from the Mekong basin. However, several of these latter taxa were better supported when MSC species delimitation methods were applied to the combined mtDNA and ITS datasets. The ITS2 secondary structure retrieved one unnamed Mekong basin species that was not uncovered by the other methods when applied to ITS2 sequences. In conclusion, based on an integrative taxonomic workflow, 26 Glyphidrilus candidate species were retained and two remained to be confirmed. As such, this study provides evidence to suggest nine species new to science and to synonymize 12 nominal morphospecies. It also illustrates that the uncritical use of COI as a universal DNA barcode may overestimate species diversity because COI may be unable to distinguish between divergent conspecific lineages and different candidate species.

An earthworm-inspired soft robot with perceptive artificial skin.

The bodies of earthworms are composed of repeating deformable structural units, called metameres, that generate the peristaltic body motions required for limbless underground burrowing and above-ground crawling. Metameres are actuated by circular and longitudinal muscles that are activated synchronously by the animals' nervous systems. A significant number of the neural-motor feedback loops function with sensory input gathered by the animals' highly sensitive skins, which are embedded with light, pressure and chemical receptors. In this paper, adopting the basic mechanisms employed by earthworms, we propose a new type of pneumatically-driven soft robot that can travel inside pipes by mimicking the motions and replicating the functionalities of a single metamere. Furthermore, we introduce a sensing scheme for feedback control that mimics the mechanical sensory capabilities of an earthworm's skin, which was developed upon stretchable liquid circuits capable of measuring strain and detecting pressure variations. The suitability of the proposed approach is demonstrated through several controlled locomotion experiments, employing two different robotic prototypes.

Anticipating the response of the Brazilian giant earthworm (Rhinodrilus alatus) to climate change: implications for its traditional use.

Our understanding of the impacts of ongoing global warming on terrestrial species has increased significantly during the last several years, but how climatic change has affected, and will affect, the distribution of earthworms remains largely unknown. We used climate niche modeling to model the current distribution of the giant earthworm Rhinodrilus alatus - an endemic species of the Cerrado Domain in Brazil, which is traditionally harvested and commercialized for fishing bait. R. alatus is sensitive to environmental changes because climate, in synergy with soil attributes, determine its annual reproductive cycle and distribution. The paleoclimatic reconstructions predict important geographical shifts from LGM (~21,000 yBp) to the present potential distribution of R. alatus: range expansion, fragmentation, and shrinkage of the current core area. Further, the 2070 scenarios predict substantial shrink and losses of stable areas. Our results indicate that climate change will not only affect the extent of the distribution, but will also promote significant fragmentation and a geographical shift to outside of the currently recognized geographical boundaries. In this context, populations of R. alatus would decline and traditional harvesting would collapse, requiring immediate implementation of management and conservation measures for the species and economically sustainable alternatives for the local community.

The role of CuZn- and Mn-superoxide dismutases in earthworm Eisenia andrei kept in two distinct field-contaminated soils.

Polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs), together with polycyclic aromatic hydrocarbons (PAHs), represent highly toxic and persistent organic environmental pollutants, especially due to their capability for bioaccumulation in fatty tissues. To observe the environmentally relevant effect of these compounds on earthworms, two soils naturally contaminated with PCDD/Fs and PAHs were used in our experiments. We focused on the role of CuZn- and Mn-superoxide dismutases. We assembled a full-length sequences of these molecules from Eisenia andrei earthworm and confirmed their activity. We demonstrated the significant reduction of CuZn-SOD on both mRNA and enzyme activity levels and increased levels of reactive oxygen species in earthworms kept in PCDD/F-polluted soil, which corresponds to the observed histopathologies of the earthworm intestinal wall and adjacent chloragogenous tissue. The results show an important role of CuZn-SOD in earthworm tissue damage caused by PCDD/Fs present in soil. We did not detect any significant changes in the mRNA expression or activity of Mn-SOD in these earthworms. In earthworms maintained in PAH-polluted soil the activity of both CuZn-SOD and Mn-SOD significantly increased. No histopathological changes were detected in these worms, however significant decrease of coelomocyte viability was observed. This reduced viability was most likely independent of oxidative stress.

Complex taxonomy of the 'brush tail' peregrine earthworm Pontoscolex corethrurus.

Pontoscolex corethrurus is the most widespread earthworm species in tropical and sub-tropical zones and one of the most studied in soil science. Although, ecological interactions of P. corethrurus with its environment are well documented, the taxonomic status of the species remains unclear. In this study, we investigated phylogenetic relationships within the genus Pontoscolex, in particular focusing on morphologically indistinguishable (i.e., cryptic) lineages. A total of 792 specimens collected from 25 different countries and islands all over the world were analyzed using two mitochondrial (COI and 16S rDNA) and two nuclear (internal transcribed spacers 2 and 28S rDNA) markers, and a total of 11 morphological characters both internal and external were investigated in all genetically characterized lineages. A large-scale multilocus sequence data matrix was also obtained for Pontoscolex spp. specimens using the Anchored Hybrid Enrichment (AHE) method. Multilocus phylogenetic and phylogenomic analyses, combined with species delimitation methods; including single locus (mPTP, ABGD) and multilocus (BPP) approaches, revealed congruent results. Four cryptic species were supported within the P. corethrurus species complex, and four potentially new species within the genus Pontoscolex. One widespread lineage (L1), within P. corethrurus complex was observed in the current population of Fritz Müller's garden where P. corethrurus was first described in 1856. Cryptic lineages were observed in sympatry at several localities. This, in combination with observed heteroplasmy in COI gene in one population raises an important question of reproductive isolation between these species.

Earthworm coelomocyte extracellular traps: structural and functional similarities with neutrophil NETs.

Invertebrate immunity is associated with natural mechanisms that include cellular and humoral elements, similar to those that play a role in vertebrate innate immune responses. Formation of extracellular traps (ETs) is a newly discovered mechanism to combat pathogens, operating not only in vertebrate leucocytes but also in invertebrate immune cells. The ET components include extracellular DNA (exDNA), antimicrobial proteins and histones. Formation of mammalian ETs depends on enzymes such as neutrophil elastase, myeloperoxidase, the citrullination of histones and protease activity. It was confirmed that coelomocytes-immunocompetent cells of the earthworm Eisenia andrei-are also able to release ETs in a protease-dependent manner, dependent or independent of the formation of reactive oxygen species and rearrangement of the cell cytoskeleton. Similar to vertebrate leukocytes (e.g., neutrophil), coelomocytes are responsible for many immune functions like phagocytosis, cytotoxicity and secretion of humoral factors. ETs formed by coelomocyte analogues to neutrophil ETs consist of exDNA, histone H3 and attached to these structures proteins, e.g., heat shock proteins HSP27. The latter fact confirms that mechanisms of ET release are conserved in evolution. The study on Annelida adds this animal group to the list of invertebrates capable of ET release, but most importantly provides insides into innate mechanisms of ET formation in lower animal taxa.

Origami-based earthworm-like locomotion robots.

Inspired by the morphology characteristics of the earthworms and the excellent deformability of origami structures, this research creates a novel earthworm-like locomotion robot through exploiting the origami techniques. In this innovation, appropriate actuation mechanisms are incorporated with origami ball structures into the earthworm-like robot 'body', and the earthworm's locomotion mechanism is mimicked to develop a gait generator as the robot 'centralized controller'. The origami ball, which is a periodic repetition of waterbomb units, could output significant bidirectional (axial and radial) deformations in an antagonistic way similar to the earthworm's body segment. Such bidirectional deformability can be strategically programmed by designing the number of constituent units. Experiments also indicate that the origami ball possesses two outstanding mechanical properties that are beneficial to robot development: one is the structural multistability in the axil direction that could contribute to the robot control implementation; and the other is the structural compliance in the radial direction that would increase the robot robustness and applicability. To validate the origami-based innovation, this research designs and constructs three robot segments based on different axial actuators: DC-motor, shape-memory-alloy springs, and pneumatic balloon. Performance evaluations reveal their merits and limitations, and to prove the concept, the DC-motor actuation is selected for building a six-segment robot prototype. Learning from earthworms' fundamental locomotion mechanism-retrograde peristalsis wave, seven gaits are automatically generated; controlled by which, the robot could achieve effective locomotion with qualitatively different modes and a wide range of average speeds. The outcomes of this research could lead to the development of origami locomotion robots with low fabrication costs, high customizability, light weight, good scalability, and excellent re-configurability.

Molecular phylogeny and systematics of native North American lumbricid earthworms (Clitellata: Megadrili).

The family Lumbricidae is arguably the most well-known and well-studied earthworm group due to its dominance in the European earthworm fauna and its invasion in temperate regions worldwide. However, its North American members, especially the genus Bimastos Moore, 1893, are poorly understood. We revised the systematics of the genus Bimastos and tested the hypothesis of the monophyly of North American lumbricids using morphological characters and eight molecular markers. Phylogenetic analyses based on our extensive sampling of Bimastos and inclusion of Dendrodrilus and Allolobophoridella indicated a well-supported clade containing Bimastos and Eisenoides Gates, 1969, and provided the first evidence supporting that North American lumbricids are monophyletic. Assuming the available divergence time estimations and dating of land bridges are correct, it would suggest that the ancestor of this clade arrived North America through Beringia or the De Geer route during Late Cretaceous, and since then the clade has diverged from its Eurasian sister group, Eisenia. The peregrine genera Dendrodrilus and Allolobophoridella are nested within the Bimastos clade; we propose to treat them as junior synonyms of the genus Bimastos, and, contradictory to the commonly held belief of being European, they are indeed part of the indigenous North American earthworm fauna. Morphological characters, such as red-violet pigmentation, proclinate U-shaped nephridial bladders and calciferous diverticula in segment 10 further support this placement. The East Mediterranean-Levantine Spermophorodrilus Bouché, 1975 and Healyella Omodeo & Rota, 1989 are nested within the Dendrobaena sensu lato clade; therefore their close relationship with the North American Bimastos is refuted. Species fit the revised diagnosis of Bimastos are reviewed and keyed, and a new species, Bimastos schwerti sp. nov., is described.

Infection of Oligochaetes, Limnodrilus hoffmeisteri (Annelida: Oligochaeta), in the Nasal Cavity of a Chinese Man.

The infection by Limnodrilus hoffmeisteri Claparède, 1862 (Oligochaeta: Tubificinae) in humans is relatively uncommon. The present report is to describe an incidental human infection with oligochaetes in the nasal cavity of a Chinese man, a 25-year-old man residing in Zhangjiakou city, Hebei province, China presenting with nose bleed, severe itching, continuous sneezing, and rhinorrhea. A lot of oligochaete worms were found in the nasal discharge of the patient. The detected worms were identified as Limnodrilus hoffmeisteri (Annelida: Oligochaeta) based on morphological and molecular characteristics. This incidental L. hoffmeisteri nasal infection is the first case in China and indicates that oligochaete worms can be encountered in humans.

Croatian freshwater oligochaetes: species diversity, distribution and relationship to surrounding countries.

This paper presents a checklist of the freshwater oligochaetes of Croatia, including data related to the ecoregions, river basins and habitat types in which species were recorded. The checklist is based on literature data and new records from unpublished research conducted since 1975. A total of 71 freshwater oligochaete species were recorded at 345 sampling sites. The family Naididae was most species rich (31 species), followed by the family Tubificidae (27 species), Lumbriculidae (6 species) and Pristinidae (4 species). The families Haplotaxidae, Propappidae and Lumbricidae were least diverse, with only one species recorded for each. Approximately two-thirds of the oligochaete species occurred in both the Dinaric western Balkan and the Pannonian lowland ecoregions. Similar patterns in species richness were detected for the Black Sea and the Adriatic Sea basins. Species richness varied between habitat types, with rivers as the most speciose habitats. In comparison to adjacent countries, the Croatian oligochaete fauna was most similar to that of Bosnia and Herzegovina, Hungary and Austria.

Endemic earthworms (Oligochaeta: Lumbricidae) of the Balkan Peninsula: a review.

A list of the endemic earthworms of the Balkan Peninsula is presented. Comprehensive information on the ecology, distribution on the Balkan Peninsula and zoogeographical type of all endemics is given. The list comprises 90 species and subspecies, belonging to 11 genera of the family Lumbricidae. The largest number of the Balkan endemic earthworms belongs to a narrow range group (63.3%). Broad range endemic species take part with 36.7%. Our study shows that the degree of endemism on the Balkan Peninsula is extremely high (about 40%) suggesting an important process of autochthonous speciation on the Balkan Peninsula. This appearance is attributable to relative isolation of the mountains compared to the lowlands within the context of paleoenvironmental changes.

New species of the earthworm genus Zapatadrilus (Clitellata, Acanthodrilidae) from northern Mexico.

Three new species of the earthworm genus Zapatadrilus are described from Tamaulipas, Mexico: Zapatadrilus aurelius sp. nov., Zapatadrilus huastecus sp. nov., and Zapatadrilus montezumensis sp. nov. Delimitation of the new species was supported by morphological and molecular (genetic distances) evidence. Diagnostic characters of the three new species include: tubulo-racemose prostates in segments 18 and 20, penial setae absent, typhlosole present and intestine beginning in 17/18. Z. montezumensis sp. nov. is separated by its metandric condition, Z. aurelius sp. nov. by the last hearts in 13 and Z. huastecus sp. nov. by the shape of the spermathecae and patterns of genital markings.