A "Dirty" Footprint: Macroinvertebrate diversity in Amazonian Anthropic Soils.

Amazonian rainforests, once thought to be pristine wilderness, are increasingly known to have been widely inhabited, modified, and managed prior to European arrival, by human populations with diverse cultural backgrounds. Amazonian Dark Earths (ADEs) are fertile soils found throughout the Amazon Basin, created by pre-Columbian societies with sedentary habits. Much is known about the chemistry of these soils, yet their zoology has been neglected. Hence, we characterized soil fertility, macroinvertebrate communities, and their activity at nine archeological sites in three Amazonian regions in ADEs and adjacent reference soils under native forest (young and old) and agricultural systems. We found 673 morphospecies and, despite similar richness in ADEs (385 spp.) and reference soils (399 spp.), we identified a tenacious pre-Columbian footprint, with 49% of morphospecies found exclusively in ADEs. Termite and total macroinvertebrate abundance were higher in reference soils, while soil fertility and macroinvertebrate activity were higher in the ADEs, and associated with larger earthworm quantities and biomass. We show that ADE habitats have a unique pool of species, but that modern land use of ADEs decreases their populations, diversity, and contributions to soil functioning. These findings support the idea that humans created and sustained high-fertility ecosystems that persist today, altering biodiversity patterns in Amazonia.

Phylogenomic analyses of Crassiclitellata support major Northern and Southern Hemisphere clades and a Pangaean origin for earthworms.

BACKGROUND: Earthworms (Crassiclitellata) are a diverse group of annelids of substantial ecological and economic importance. Earthworms are primarily terrestrial infaunal animals, and as such are probably rather poor natural dispersers. Therefore, the near global distribution of earthworms reflects an old and likely complex evolutionary history. Despite a long-standing interest in Crassiclitellata, relationships among and within major clades remain unresolved. METHODS: In this study, we evaluate crassiclitellate phylogenetic relationships using 38 new transcriptomes in combination with publicly available transcriptome data. Our data include representatives of nearly all extant earthworm families and a representative of Moniligastridae, another terrestrial annelid group thought to be closely related to Crassiclitellata. We use a series of differentially filtered data matrices and analyses to examine the effects of data partitioning, missing data, compositional and branch-length heterogeneity, and outgroup inclusion. RESULTS AND DISCUSSION: We recover a consistent, strongly supported ingroup topology irrespective of differences in methodology. The topology supports two major earthworm clades, each of which consists of a Northern Hemisphere subclade and a Southern Hemisphere subclade. Divergence time analysis results are concordant with the hypothesis that these north-south splits are the result of the breakup of the supercontinent Pangaea. CONCLUSIONS: These results support several recently proposed revisions to the classical understanding of earthworm phylogeny, reveal two major clades that seem to reflect Pangaean distributions, and raise new questions about earthworm evolutionary relationships.

Phylogenetic evaluation of Amynthas earthworms from South China reveals the initial ancestral state of spermathecae.

Our knowledge of the phylogeny of the earthworm genus Amynthas under the family Megascolecidae, which is comprised of a huge number of species, is very limited compared to the better-known and much smaller family Lumbricidae. In order to investigate the phylogenetic relationships among the species within the genus Amynthas, which is the largest genus of the Megascolecidae family, nuclear and mitochondrial DNA sequences of 77 species, including 76 in-group Amynthas species collected from South China and 1 out-group species, were analyzed. A 5402bp segments composed of whole nuclear 18S rDNA and the mitochondrial genes COI, COII, ND1, 12S, and 16S was assembled from 77 species. Maximum Likelihood and Bayesian analyses of the concatenated sequences were performed. The results revealed evolution of two geographically independent lineages, both showing the ancestral state of two pairs of spermatheca (Sp.p 7/8/9). We found the species groups described by Sims and Easton (1972) to be non-monophyletic, and the origin of the parthenogenetic species group to likely be a quadthecal ancestor. These results provide modest evidence in support of an Indochinese peninsula origin of the Chinese Amynthas species and divergence of the genus once it had spread to mainland China. The findings of this study are consistent with a divergence scenario that resulted in at least one branch spreading to the Southeast of China and another branch spreading to the Southwest of China, but further research is required to confirm this interpretation of the Amynthas phylogeny.

Underground evolution: new roots for the old tree of lumbricid earthworms.

Earthworms belonging to the family Lumbricidae are extremely abundant in terrestrial temperate regions. They affect soil properties and nutrient cycling, thus shaping plant community composition and aboveground food webs. Some lumbricids are also model organisms in ecology and toxicology. Despite the intense research efforts dedicated to lumbricids over the last 130years, the evolutionary relationships and taxonomic classification of these organisms are still subject to great debate. Resolution of their systematics is hampered by the structural simplicity of the earthworm body plan and the existence of cryptic species. We sampled 160 earthworm specimens belonging to 84 lumbricid species (28 genera) and 22 Lumbricoidea outgroups, sequenced two nuclear genes, four mitochondrial genes and seven mitochondrial tRNAs and examined 22 morphological characters. We then applied a combination of phylogenetic methods to generate the first robust genus-level phylogeny of the Lumbricidae. Our results show that the current Lumbricidae classification and the underlying hypotheses of character evolution must be revised. Our chronogram suggests that lumbricids emerged in the Lower Cretaceous in the holarctic region and that their diversification has been driven by tectonic processes (e.g. Laurasia split) and geographical isolation. Our chronogram and character reconstruction analysis reveal that spermathecae number does not follow a gradual pattern of reduction and that parthenogenesis arose from sexual relatives multiple times in the group; the same analysis also indicates that both epigeic and anecic earthworms evolved from endogeic ancestors. These findings emphasize the strong and multiple changes to which morphological and ecological characters are subjected, challenging the hypothesis of character stasis in Lumbricidae.

Three new earthworms of the Amynthas corticis-group (Clitellata: Megascolecidae) from the Nam Et-Phouleoi, Laos.

Three new earthworms of the Amynthas corticis-group (Clitellata: Megascolecidae) from Phouleoi Mountain, Lao PDR. Earthworm specimens were collected from Mt. Phouleoi, Viengthong District, Houaphanh Province, Lao PDR. The species belong to the pheretimoid earthworms. All three holandric species key out to the A. corticis-group in Sims & Easton (1972), having spermathecal pores in 5/68/9. The new species are: Amynthas ammalinei sp. nov., Amynthas xayi sp. nov., and Amynthas piyakarnae sp. nov. Amynthas ammalinei sp. nov. has male pores superficial on small round porophores, 0.160.31 circumference apart. Amynthas xayi sp. nov. has male pores superficial in XVIII at centers of round porophores, 0.170.29 circumference apart. Amynthas piyakarnae sp. nov. has male pores superficial on transverse elevated elongate oval pads equatorial on XVIII, pads surrounded by 34 small outer rings, 0.250.31 circumference apart.

Three new earthworm species of the genus Amynthas (Clitellata: Megascolecidae) from Mt. Chiak National Park, Korea.

Earthworm specimens collected from Mt. Chiak, National Park, Korea were found to represent three new species of megascolecid earthworms: Amynthas chiakensis sp. nov., Amynthas gyeongriae sp. nov., and Amynthas wonjuensis sp. nov. Amynthas chiakensis sp. nov. has two pairs of spermathecae in VII and VIII, small transverse oval male porophores each with C-shaped small patches of genital papillae, 0.22-0.31 circumference apart. Amynthas gyeongriae sp. nov. has spermathecae in VI-VIII, male field with large circular-shaped raised pads and seminal grooves, with pores 0.16-0.28 circumference apart. Amynthas wonjuensis sp. nov. has spermathecae in VI and VII, male pores superficial in XVIII on small oval-shaped white porophores lateral to large roughly circular raised genital papillae, 0.15 circumference apart.

New Ocnerodrilidae genera, species and records from Brazil (Annelida: Crassiclitellata).

We describe three new species of Eukerria, six of Kerriona, one of Ocnerodrilus and two of Belladrilus (Clitellata: Ocnerodrilidae) from Brazil, mostly from wet habitats including bromeliad leaf axils, plus some from forest soils in Bahia state. We also provide new morphological and distribution data on Kerriona luederwaldti Michaelsen, 1924. We describe the new genus Pauqueba and its two new species, both from bromeliad leaf axils and forest floor litter in the state of Bahia. It has two pairs of calciferous glands, the balantine reduction of the male terminalia but spermathecae in ix, and no gizzard. The new genus Parabauba found in deeper (30 cm) soil layers is distinctive for the combination of two pairs of calciferous glands, a large gizzard in v, acanthodriline male terminalia, and no typholosole. The new genus Diplomoela from a mesic soil in Bahia is meronephric, unusually large for the Ocnerodrilidae, and has two well-developed gizzards.

Distribution and diversity of earthworms in different land use systems in Rio Grande do Sul, Brazil.

The southernmost state of Brazil, Rio Grande do Sul, includes both the Pampa and Atlantic Forest biomes, and covers an area of around 284 thousand km2. Since the last checklist for the state, published in 2012, many additional sites have been sampled. Hence, we provide here a full list of earthworm species and their distribution in different municipalities and land use systems in the state. Data were obtained from the literature, museums, and other earthworm collections and recent sampling efforts. Records for 19 additional species are reported here for the first time, raising the total to 78 species/subspecies currently known from Rio Grande do Sul, from the families Acanthodrilidae (5), Benhamiidae (3), Lumbricidae (13), Megascolecidae (11), Ocnerodrilidae (22), Almidae (2), Glossoscolecidae (18) and Rhinodrilidae (5). Alexidrilus Righi, 1971 is synonymized with Urobenus Benham, 1886, as both species in the genus (A. littoralis Ljungström, 1972 and A. lourdesae Righi, 1971) have similar morphology to the type species Urobenus brasiliensis Benham, 1886. Most of the native species/subspecies in the state (39), including an important number of new species, were found in native vegetation with lesser disturbance, such as swamps, native forests and pastures. On the other hand, the three peregrine and 27 exotic species (especially Pontoscolex corethrurus, Eukerria spp., lumbricids, megascolecids, Dichogaster spp., and Microscolex spp.) dominated in disturbed sites, such as compost piles, urban areas, rice and other crops, and cultivated pastures. Considering the geographic extension and the many unsampled sites in the state, further collection efforts are necessary and will certainly reveal new species, as evidenced here.

Earthworms from natural and managed ecosystems in Southern Bahia, Brazil.

The earthworms (Crassiclitellata) of the Northern Atlantic Forest region are poorly known, and many new species are expected to be found in the region. Hence, quantitative and qualitative samples were taken in the Atlantic Forest region of southern Bahia State, Brazil, at eight sites to assess species presence and abundance in different land uses (forests, pastures, plantations). Earthworms were also qualitatively collected at an additional eight sites. Only one to two species per site were found in quantitative samples, while qualitative samples generally resulted in higher species recoveries, with highest richness observed at the native Atlantic Forest of Veracel in Porto Seguro. Pontoscolex corethrurus (Müller, 1857) was the dominant species at all sites and in most land use systems, probably favored by human migration and agricultural activities; it was only absent in one primary forest site where native Ocnerodrilidae species predominated. In total at least 14 species were found of which eight were new, belonging to the genus Rhinodrilus and three new genera in the Ocnerodrilidae family (Pauqueba, Parabauba and Diplomoela). Contrary to sites in Southern and Southeastern Brazil, where many native species belong to the Glossoscolecidae family, in southern Bahia, Ocnerodrilidae species tend to be more prevalent, occupying various habitats. More intensive sampling of these habitats, including surface litter, in and under fallen logs and dead tree trunks, under rocks, in bromeliad leaf tanks and deeper soil layers is essential in order to properly characterize earthworm communities in Brazilian Atlantic Forests.

Earthworms (Clitellata, Megadrili) of the world: an updated checklist of valid species and families, with notes on their distribution.

In the current paper we present an updated checklist of all the megadrile earthworms (Crassiclitellata: Annelida) in the world, and notes on the distribution of families worldwide. Biogeographic responses to geological phenomena including plate tectonics, as well as to past and present climate and habitat distributions, are the main factors determining the present distribution of earthworm families. A total of ca. 5,738 species/subspecies (5,406 species and 332 unique subspecies; i.e., not counting the nomino-typical subspecies) belonging to 23 families (including one non-crassiclitellate family: Moniligastridae) are currently recognized worldwide, of which three families (Tritogeniidae and Kazimierzidae from Southern Africa and Arecoidae, a new family from Brazil described herein), 35 genera and close to 1200 new taxa (including subspecies) were described in the 21st century. Nonetheless, the large number of still undescribed species will likely increase this value to well over 8,000 species. Ten families are monospecific and/or monogeneric and have a mostly restricted distribution. On the other hand, more than 87 widespread cosmopolitan species have been catalogued, some of them with important invasive potential, belonging mainly to families Lumbricidae, Acanthodrilidae, Benhamiidae, Megascolecidae, Rhinodrilidae and Ocnerodrilidae. Taxonomic housekeeping was performed for the preoccupied Rhinodrilidae genus Tairona Righi - herein substituted by Taironina nom. nov., and Guarani camaqua Rodríguez & Lima was reinstated and removed from synonymy with Criodrilus lacuum Hoffmeister, 1845, resulting in a wider definition of the Almidae family. Furthermore, Amynthas maximalis nom. nov. is proposed herein as a substitution name for the preoccupied name Amynthas maximus Qiu & Dong, 2019, and Arecoidae is proposed herein as a new monotypic family for the aquamegadrile species Areco reco Righi, Ayres & Bittencourt, 1978.

Amazonian earthworm biodiversity is heavily impacted by ancient and recent human disturbance.

Despite the importance of earthworms for soil formation, more is needed to know about how Pre-Columbian modifications to soils and the landscape. Gaining a deeper understanding is essential for comprehending the historical drivers of earthworm communities and the development of effective conservation strategies in the Amazon rainforest. Human disturbance can significantly impact earthworm diversity, especially in rainforest soils, and in the particular case of the Amazonian rainforest, both recent and ancient anthropic practices may be important. Amazonian Dark Earths (ADEs) are fertile soils found throughout the Amazon Basin, created by sedentary habits and intensification patterns of pre-Colombian societies primarily developed in the second part of the Holocene period. We have sampled earthworm communities in three Brazilian Amazonian (ADEs) and adjacent reference soils (REF) under old and young forests and monocultures. To better assess taxonomic richness, we used morphology and the barcode region of the COI gene to identify juveniles and cocoons and delimit Molecular Operational Taxonomic Units (MOTUs). Here we suggest using Integrated Operational Taxonomical units (IOTUs) which combine both morphological and molecular data and provide a more comprehensive assessment of diversity, while MOTUs only rely on molecular data. A total of 970 individuals were collected, resulting in 51 taxonomic units (IOTUs, MOTUs, and morphospecies combined). From this total, 24 taxonomic units were unique to REF soils, 17 to ADEs, and ten were shared between both soils. The highest richness was found in old forest sites for ADEs (12 taxonomic units) and REFs (21 taxonomic units). The beta-diversity calculations reveal a high species turnover between ADEs and REF soils, providing evidence that ADEs and REFs possess distinct soil biota. Furthermore, results suggest that ADE sites, formed by Pre-Columbian human activities, conserve a high number of native species in the landscape and maintain a high abundance, despite their long-term nature.

Two new earthworms of the Pheretima sangirensis species group (Clitellata: Megascolecidae) from Mountain Province, Philippines.

Two new species of the genus Pheretima are described from Mt. Amuyao and Mt. Lamagan, Mountain Province, Philippines, namely Pheretima riparianensis sp. nov. and Pheretima bontocensis sp. nov. Both new species belong to the P. sangirensis species group characterized by having only one pair of spermathecal pores in 7/8. Pheretima riparianensis sp. nov. has distance between spermathecal pores 12 mm; copulatory bursae openings 0.11 circumference ventrally apart. Pheretima bontocensis sp. nov. has distance between spermathecal pores 1.4 mm; copulatory bursae openings 0.10 circumference ventrally apart.

Three uncharted endemic earthworm species of the genus Eutyphoeus (Oligochaeta: Octochaetidae) from Mizoram, India.

Integrative approach of taxonomy drives us to the discovery of three new species of the genus Eutyphoeus Michaelsen 1900, namely Eutyphoeus phawngpuiensis sp. nov., Eutyphoeus serei sp. nov. and Eutyphoeus tawi sp. nov. from protected forests of Mizoram, India. E. phawngpuiensis sp. nov. belongs to the Eutyphoeus hastatus group, and is characterized by holandric male organs, having spermathecal pores at a or ab, bidiverticulate spermathecae, and lack of genital marking glands. While, E. tawi sp. nov. has spermathecal pores at b or lateral to b, without lateral intestinal caeca. E. serei sp. nov. belongs to the Eutyphoeus gigas group, and is distinguished by having metandric male organs, lacking female pore of right side, and having spoon shaped tip of penial setae without ornamentation. Molecular characterization using coi gene marker also supports the findings. The maximum intraspecific distances and distance to the nearest neighbour of E. phawngpuiensis sp. nov., E. serei sp. nov. and E. tawi sp. nov. were recorded 3.5%, 9.37%; 2.35%, 14.83%; and 2.28%, 12.86% respectively. The key to Eutyphoeus species of India was also updated.

Amynthas corticis genome reveals molecular mechanisms behind global distribution.

Earthworms (Annelida: Crassiclitellata) are widely distributed around the world due to their ancient origination as well as adaptation and invasion after introduction into new habitats over the past few centuries. Herein, we report a 1.2 Gb complete genome assembly of the earthworm Amynthas corticis based on a strategy combining third-generation long-read sequencing and Hi-C mapping. A total of 29,256 protein-coding genes are annotated in this genome. Analysis of resequencing data indicates that this earthworm is a triploid species. Furthermore, gene family evolution analysis shows that comprehensive expansion of gene families in the Amynthas corticis genome has produced more defensive functions compared with other species in Annelida. Quantitative proteomic iTRAQ analysis shows that expression of 147 proteins changed in the body of Amynthas corticis and 16 S rDNA sequencing shows that abundance of 28 microorganisms changed in the gut of Amynthas corticis when the earthworm was incubated with pathogenic Escherichia coli O157:H7. Our genome assembly provides abundant and valuable resources for the earthworm research community, serving as a first step toward uncovering the mysteries of this species, and may provide molecular level indicators of its powerful defensive functions, adaptation to complex environments and invasion ability.

A neotype for Pontoscolex corethrurus (Müller, 1857) (Clitellata).

Following many decades of work on the taxonomy, biology and ecology of the globally-distributed tropical earthworm Pontoscolex corethrurus (Müller, 1857), morphological and molecular data have shown that the stability and effectiveness of nomenclature depends on the designation of a neotype from the type locality. We do that, with all the required justifications, and provide sufficient information to permit the correct identification of this species.

Phylogenomic Analysis of a Putative Missing Link Sparks Reinterpretation of Leech Evolution.

Leeches (Hirudinida) comprise a charismatic, yet often maligned group of organisms. Despite their ecological, economic, and medical importance, a general consensus on the phylogenetic relationships of major hirudinidan lineages is lacking. This absence of a consistent, robust phylogeny of early-diverging lineages has hindered our understanding of the underlying processes that enabled evolutionary diversification of this clade. Here, we used an anchored hybrid enrichment-based phylogenomic approach, capturing hundreds of loci to investigate phylogenetic relationships among major hirudinidan lineages and their closest living relatives. Our results suggest that a dramatic reinterpretation of early leech evolution is warranted. We recovered Branchiobdellida as sister to a clade that includes all major lineages of hirudinidans, but found Acanthobdella to be nested within Oceanobdelliformes. These results cast doubt on the utility of Acanthobdella as a "missing link" used to explain the origin of blood-feeding in hirudineans. Further, our results support a deep divergence between predominantly marine and freshwater lineages, while not supporting the reciprocal monophyly of jawed and proboscis-bearing leeches. To sum up, our phylogenomic resolution of early-diverging leeches provides a necessary foundation for illuminating the evolution of host-symbiont associations and key adaptations that have allowed leeches to colonize a wide diversity of habitats worldwide.

Description of a new Central African earthworm, Petroscolex centenarius gen. et sp. nov. (Crassiclitellata, Eudrilidae), celebrating the 100th birthday of Pietro Omodeo.

Prof. Pietro Omodeo (University of Siena, Italy), the world-renowned earthworm taxonomist and evolutionary biologist, was born in Cefalù, Sicily, Italy on the 27th September, 1919. He celebrates his 100th birthday in 2019 and members of the international community of earthworm taxonomists salute him with Petroscolex centenarius gen. et sp. nov., a new megadrile taxon discovered in 1991 by him but which has not been formally described until now. The many important contributions of Omodeo to oligochaetological research are briefly mentioned.

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.