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Science (New York, N.Y.) Jan 2021Phillips (Reports, 25 October 2019, p. 480) incorrectly conclude that tropical earthworm communities are less diverse and abundant than temperate communities. This...
Phillips (Reports, 25 October 2019, p. 480) incorrectly conclude that tropical earthworm communities are less diverse and abundant than temperate communities. This result is an artifact generated by some low-quality datasets, lower sampling intensity in the tropics, different patterns in richness-area relationships, the occurrence of invasive species in managed soils, and a focus on local rather than regional richness.
Topics: Animals; Oligochaeta; Soil
PubMed: 33414190
DOI: 10.1126/science.abe4629 -
Comparative Biochemistry and... Aug 2019Freezing, dehydration, salinity variations, hypoxia or anoxia are some of the environmental constraints that many organisms must frequently endure. Organisms adapted to... (Review)
Review
Freezing, dehydration, salinity variations, hypoxia or anoxia are some of the environmental constraints that many organisms must frequently endure. Organisms adapted to these stressors often reduce their metabolic rates to maximize their chances of survival. However, upon recovery of environmental conditions and basal metabolic rates, cells are affected by an oxidative burst that, if uncontrolled, leads to (oxidative) cell damage and eventually death. Thus, a number of adapted organisms are able to increase their antioxidant defenses during an environmental/functional hypoxic transgression; a strategy that was interpreted in the 1990s as a "preparation for oxidative stress" (POS). Since that time, POS mechanisms have been identified in at least 83 animal species representing different phyla including Cnidaria, Nematoda, Annelida, Tardigrada, Echinodermata, Arthropoda, Mollusca and Chordata. Coinciding with the 20th anniversary of the postulation of the POS hypothesis, we compiled this review where we analyze a selection of examples of species showing POS-mechanisms and review the most recent advances in understanding the underlying molecular mechanisms behind those strategies that allow animals to survive in harsh environments.
Topics: Adaptation, Physiological; Animals; Annelida; Dehydration; Evolution, Molecular; Freezing; Hypoxia; Mollusca; Oxidative Stress; Salinity
PubMed: 30978470
DOI: 10.1016/j.cbpa.2019.04.004 -
Zootaxa May 2023Two new species of Marphysa Quatrefages, 1866 are described from the southeast coast of Australia. With the presence of only compound spinigers and the branchiae present...
Two new species of Marphysa Quatrefages, 1866 are described from the southeast coast of Australia. With the presence of only compound spinigers and the branchiae present over many chaetigers, Marphysa baudini n. sp. belongs to the Sanguinea-group. This species has ventral cirri with an inflated base and digitiform tip and thick and wide anodont pectinate chaetae, with 3-5 internal long and thick teeth. With the presence of only compound falcigers, Marphysa davidattenboroughi n. sp., belongs to the "Aenea-group". This species is characterised by the presence of a bilobed prostomium, a single pair of pygidial cirri and by the presence of thick, and wide anodont pectinate chaetae with 4-6 long internal and thick teeth.
Topics: Animals; Annelida; Polychaeta; South Australia
PubMed: 37518328
DOI: 10.11646/zootaxa.5277.1.5 -
Journal of Morphology Jan 2021Ovaries of Haplotaxis sp. were studied in active and nonactive states, that is, in a sexually mature specimen and in specimens outside of the reproductive period. Two...
Ovaries of Haplotaxis sp. were studied in active and nonactive states, that is, in a sexually mature specimen and in specimens outside of the reproductive period. Two pairs of ovaries were found in segments XI and XII. Especially in the nonactive state, they were in close contact with copulatory glands. Each ovary was composed of germ cells interconnected with syncytial cysts, which were enveloped by a layer of somatic cells. Within cysts each germ cell had one ring canal connecting it to the common anuclear cytoplasmic mass called a cytophore. During oogenesis clustering germ cells differentiated into nurse cells and oocytes; thus, the oogenesis was recognized as meroistic. Vitellogenic oocytes were detached from the ovaries and continued yolk absorption within the body cavity. Because recent studies have shown the variety of ovaries and germ line cyst organization in clitellates and suggest their evolutionary conservatism at the family or subfamily level, the data presented here can be valid in understanding the phylogenetic relationships among Clitellata. In this context, ovaries found in Haplotaxis sp. resembled those of the "Tubifex" type. "Tubifex" ovaries are characteristic for numerous microdrile taxa (tubificines, limnodriloidines, propappids, lumbriculids, and leech-like branchiobdellids) and can be regarded as the primary character for these Clitellata in which germ-line cysts are formed during early oogenesis. As the family Haplotaxidae is currently considered to be paraphyletic and the species studied here belongs to Haplotaxidae sensu stricto, our results support the close relationship of Haplotaxidae sensu stricto to the clade consisting of Lumbriculidae, Branchiobdellida, and Hirudinida, in which lumbriculids are sister to the latter two.
Topics: Animals; Female; Germ Cells; Oligochaeta; Oocytes; Oogenesis; Ovary; Phylogeny
PubMed: 33074563
DOI: 10.1002/jmor.21285 -
ELife Dec 2022Cells form networks in animal tissues through synaptic, chemical, and adhesive links. Invertebrate muscle cells often connect to other cells through desmosomes, adhesive...
Cells form networks in animal tissues through synaptic, chemical, and adhesive links. Invertebrate muscle cells often connect to other cells through desmosomes, adhesive junctions anchored by intermediate filaments. To study desmosomal networks, we skeletonised 853 muscle cells and their desmosomal partners in volume electron microscopy data covering an entire larva of the annelid . Muscle cells adhere to each other, to epithelial, glial, ciliated, and bristle-producing cells and to the basal lamina, forming a desmosomal connectome of over 2000 cells. The aciculae - chitin rods that form an endoskeleton in the segmental appendages - are highly connected hubs in this network. This agrees with the many degrees of freedom of their movement, as revealed by video microscopy. Mapping motoneuron synapses to the desmosomal connectome allowed us to infer the extent of tissue influenced by motoneurons. Our work shows how cellular-level maps of synaptic and adherent force networks can elucidate body mechanics.
Topics: Animals; Connectome; Larva; Annelida; Polychaeta; Muscles
PubMed: 36537659
DOI: 10.7554/eLife.71231 -
Molecular Phylogenetics and Evolution Jan 2023The Holarctic leech genus Haemopis currently includes 11 species, all of which are macrophagous, as opposed to their more infamous bloodfeeding counterparts among...
The Holarctic leech genus Haemopis currently includes 11 species, all of which are macrophagous, as opposed to their more infamous bloodfeeding counterparts among hirudiniform leeches. In spite of their ecological importance as fish food and predators of freshwater invertebrates, there is a paucity of data regarding morphology and genetic variation that might guide future identification efforts for members of the genus. The lack of detailed descriptions of distinguishing morphological features, coupled with the absence of a robust phylogenetic hypothesis for the genus, have conspired to prevent meaningful inferences on the natural history of the group. In an attempt to remedy this, we present new genetic (using COI, 12S rDNA, 28S rDNA and 18S rDNA) data for the majority of the known species diversity within the genus in order to both infer a phylogenetic hypothesis and to introduce authoritative DNA barcodes for the newly collected species. The potential of these barcodes is increased through rigorous morphological investigations of the specimens, with comparisons to the original literature. Our resulting phylogenetic hypothesis is agnostic as to the geographic origin of the genus, with equal probability afforded to both a Nearctic and Palearctic origin. Beyond this, we show that there is a strong tendency towards a barcoding gap within the genus, but that a distinct gap is lacking due to the relatively high genetic variation found within H. marmorata. Taken together, our results shed light on species delimitation within, and evolutionary history of, this often-neglected group of leeches.
Topics: Animals; Leeches; Phylogeny; Annelida; DNA, Ribosomal; Fresh Water
PubMed: 36283573
DOI: 10.1016/j.ympev.2022.107648 -
International Journal of Molecular... Mar 2020Echiura is one of the most intriguing major subgroups of phylum Annelida because, unlike most other annelids, echiuran adults lack metameric body segmentation. lives in...
Echiura is one of the most intriguing major subgroups of phylum Annelida because, unlike most other annelids, echiuran adults lack metameric body segmentation. lives in U-shape burrows of soft sediments. Little is known about the molecular mechanisms underlying the development of . Herein, we overviewed the developmental process from zygote to juvenile using immunohistochemistry and F-actin staining for the nervous and muscular systems, respectively. Through F-actin staining, we found that muscle fibers began to form in the trochophore phase and that muscles for feeding were produced first. Subsequently, in the segmentation larval stage, the transversal muscle was formed in the shape of a ring in an anterior-to-posterior direction with segment formation, as well as a ventromedian muscle for the formation of a ventral nerve cord. After that, many muscle fibers were produced along the entire body and formed the worm-shaped larva. Finally, we investigated the spatiotemporal expression of , , , and genes found in . During embryonic development, the striated and smooth muscle genes were co-expressed in the same region. However, the adult body wall muscles showed differential gene expression of each muscle layer. The results of this study will provide the basis for the understanding of muscle differentiation in Echiura.
Topics: Actins; Animals; Annelida; Muscle Development; Muscles; Nervous System; Transcriptome
PubMed: 32225111
DOI: 10.3390/ijms21072306 -
Zootaxa Mar 2023We describe M. fujianensis n. sp. (Annelida: Hesionidae), collected from the coast of Fujian Province, China, based on morphological and molecular analyses. Micropodarke...
We describe M. fujianensis n. sp. (Annelida: Hesionidae), collected from the coast of Fujian Province, China, based on morphological and molecular analyses. Micropodarke fujianensis n. sp. is characterized by having two pairs of minute eyes, and neurochaetae of middle segments without basal long teeth. The K2P distances of COI, 16S rRNA, 18S rRNA, 28S rRNA, and histone H3 fragments diverged from the corresponding sequences of the closest related species of Micropodarke in GenBank and BOLD Systems by 22.3%, 10.7%, 0, 1.15%, and 1.1%, respectively. Among the Micropodarke species with such DNA sequences for comparison, M. fujianensis n. sp. is most closely related to M. cf. dubia-a species collected from Daya Bay, China. An updated key to Micropodarke species is provided.
Topics: Animals; RNA, Ribosomal, 16S; Annelida; Polychaeta; China; RNA, Ribosomal, 28S; Phylogeny
PubMed: 37045225
DOI: 10.11646/zootaxa.5256.3.4 -
Functional & Integrative Genomics Aug 2022Among the annelids, earthworms are renowned for their phenomenal ability to regenerate the lost segments. The adult earthworm Eudrilus eugeniae contains 120 segments and...
Among the annelids, earthworms are renowned for their phenomenal ability to regenerate the lost segments. The adult earthworm Eudrilus eugeniae contains 120 segments and the body segments of the earthworm are divided into pre-clitellar, clitellar and post-clitellar segments. The present study denoted that clitellum plays vital role in the successful regeneration of the species. We have performed histological studies to identify among the three skin layers of the earthworm, which cellular layer supports the blastema formation and regeneration of the species. The histological evidences denoted that the proliferation of the longitudinal cell layer at the amputation site is crucial for the successful regeneration of the earthworm and it takes place only in the presence of an intact clitellum. Besides we have performed clitellar transcriptome analysis of the earthworm Eudrilus eugeniae to monitor the key differentially expressed genes and their associated functions and pathways controlling the clitellar tissue changes during both anterior and posterior regeneration of the earthworm. A total of 4707 differentially expressed genes (DEGs) were identified between the control clitellum and clitellum of anterior regenerated earthworms and 4343 DEGs were detected between the control clitellum and clitellum of posterior regenerated earthworms. The functional enrichment analysis confirmed the genes regulating the muscle mass shape and structure were significantly downregulated and the genes associated with response to starvation and anterior-posterior axis specification were significantly upregulated in the clitellar tissue during both anterior and posterior regeneration of the earthworm. The RNA sequencing data of clitellum and the comparative transcriptomic analysis were helpful to understand the complex regeneration process of the earthworm.
Topics: Animals; Gene Expression Profiling; Oligochaeta
PubMed: 35416560
DOI: 10.1007/s10142-022-00849-5 -
Zootaxa Oct 2021Polyophthalmus zhadanae sp. nov. (Annelida, Opheliidae), is described from the coast of Kuwait and Saudi Arabia (Arabian Gulf) after specimens collected in the... (Review)
Review
Polyophthalmus zhadanae sp. nov. (Annelida, Opheliidae), is described from the coast of Kuwait and Saudi Arabia (Arabian Gulf) after specimens collected in the intertidal and shallow subtidal. This new species is characterised by the body pigmentation pattern, distribution of lateral eyes, presence of small dorsal and ventral parapodial cirri and pygidial features. External and internal anatomy was described after examination with SEM and micro-CT. The presence of several body structures in the genus such as a cephalic palpode-like papilla is discussed. Furthermore, the diversity of genus Polyophthalmus and the presence of Polyophthalmus pictus (Dujardin, 1839) in the Indo-Pacific is reviewed and a key to species is provided.
Topics: Animal Distribution; Animals; Annelida; Polychaeta
PubMed: 34810858
DOI: 10.11646/zootaxa.5052.4.3