Mesenchytraeus monodiverticulus, new species, (Clitellata: Enchytraeidae) is described based on live and preserved specimens from Changbai Mountain. It is diagnosed by possessing enlarged ventral chaetae in V–VI (4–5 per bundle), nephridium holding solid unlobed postseptale, spermathecae possessing only one diverticulum and attached entally to esophagus in VII, atria cylindrical without prostate glands, and the presence of regular spermatozoal bundles in seminal vesicle (XI–XIII) with the heads of spermatozoa arranged in both ends orderly. The major differences between M. monodiverticulus and its congeners are discussed. A key to species of Mesenchytraeus that possess enlarged chaetae is provided.

Ninety-two individuals of a deep-sea harrimaniid enteropneust were imaged between 1675 m and 3225 m off the California coast. Of these, about three-fourths were positioned with their posterior regions buried in sediment or hidden by rocks, and the rest were completely exposed on the substratum. When visible, the posterior end of each worm was typically associated with a dense tangle of fecal strands. One specimen was captured and is described here as the holotype of Saxipendium implicatum. In life, it was 22 cm long, and the color of its dome-shaped proboscis, narrow collar, and anterior trunk was medium orange. No wing-like folds of the body wall protruded anywhere along the length of the worm. The proboscis complex included a stomochord and glomeruli, but neither a heart nor a pericardial cavity could be detected. Most of the dorsal collar nerve runs along an open invagination in the dorsal midline of the collar and is only roofed over very briefly at the posterior extremity of the collar. Another unusual feature is the exaggerated posterior extension of the horns of the proboscis skeleton, which projected into the anterior extremity of the trunk. The trunk commenced anteriorly with a pharyngeal/esophageal region that included a tract of ovaries on either side of the dorsal midline. The ripest ovaries contained a single oocyte approximately 700 μm in diameter (presumably this species is gonochoric, although no males have yet been collected). The gill skeleton lacked synapticles. More posteriorly, the trunk housed a long, darkly pigmented hepatic intestine without sacculations and a short, lightly pigmented post-hepatic intestine. The geographic range of S. implicatum appears to be restricted to the Davidson, Guide, and Taney Seamounts region in the eastern Pacific offshore of Central California.

Microtripus tinggiensis, a new genus and species (Amphipoda: Caprellidea: Phtisicidae), was discovered in the interstitial benthos from Pulau Tinggi, an island in the East Johor Islands Archipelago (EJIA). Microtripus tinggiensis is distinct in its reduced pereopods 3–5 (1-articulate pereopods 3, 4 and 3-articulate pereopod 5). The new genus Microtripus most closely resembles Perotripus Dougherty & Steinberg, 1953 in its elongated body segments, shorter antennae 1 and 2 and gills on pereonites 2–4 but differs from the latter by its 3-articulate flagellum of antenna 1 and 1-articulate, vestigial pereopod 3.

A small fossil sand crab carapace collected from early Eocene shallow water marine strata of the Crescent Formation exposed at Crescent Bay, Clallam County, Washington State, represents a new genus and species, Sklallamia buchanani. The carapace of S. buchanani is nearly as long as wide, is almost equally convex when viewed anteriorly, posteriorly, or laterally with smooth carapace grooves and a low median ridge, has a narrow front with anterior margins that are broadly convex on either side of the lateral margins of the ocular sinus, with broad, short ocular spines and a broad, short rostrum. This is the first confirmed fossil record of the family Albuneidae from the Pacific Basin.

Virilastacus jarai, a new species of burrowing crayfish, collected in the Intermediate Depression of the Biobío Region in central-southern Chile is described. This is the fourth species of Virilastacus, a genus endemic to Chile, to be described to date. Features that distinguish V. jarai from its congeneric species are: 1) rostral carina, short, slightly prominent and widely separated from the orbital margin; 2) pilous dorsal side of the opposable margin of the P1 propodus, as is the basal zone of the ventral side, 11 to 22 teeth on its opposable margin; 3) dorsal surface of the P1 dactylus close to the opposable border, hirsute; external distal border of the ischiopodite of the third maxilliped with a large extension that ends in the form of a right angle; 4) precervical cephalothorax with dorsal ridges absent, or with two or four; 5) areola, wide and extended; 6) telson with small, but sharp, lateral spines. Morphologically, this new species is similar to Virilastacus araucanius and V. retamali, with whom it shares 14 of the 27 morphological attributes analyzed, nine of which are common to these three species. These same attributes (13 of 14) differentiate V. jarai from V. rucapihuelensis, with whom it only shares seven morphological traits. The morphological similarity of V. jarai with V. araucanius and V. retamali contrasts with the degree of genetic divergence that exists between these species. Finally, the IUCN Red List Criteria are used to assign the conservation status of “Critically Endangered” to this new species.

Se describe Virilastacus jarai una nueva especie de camarón excavador recolectada en la Depresión Intermedia de la Región del Biobío en el centro-sur de Chile. Esta es la cuarta especie que se ha descrito de Virilastacus, género endémico de Chile. Esta nueva especie puede distinguirse de sus congéneres por tener: 1) carina rostral corta, poco prominente y muy separada del borde orbital; 2) costado dorsal del margen oponible del propodito de P1 piloso, al igual que la parte basal del costado ventral, y 11 a 22 dientes en su margen oponible; 3) superficie dorsal del dáctilo de P1 próxima al borde oponible, hirsuta; 4) borde distal externo del isquipodito del tercer maxilípedo con una gran proyección que termina en forma de ángulo recto; cefalotótrax precervical sin prominencias dorsales, o con dos o con cuatro; 5) areóla ancha y extendida; 6) y telson con espinas laterales pequeñas pero agudas. Morfológicamente, esta nueva especie se asemeja a Virilastacus araucanius y V. retamali, con las que comparte 14 de los 27 atributos morfológicos analizados, nueve de los cuales son comunes a estas tres especies. Estos mismos atributos (13 de 14) diferencian a V. jarai de V. rucapihuelensis, con quien comparte sólo siete rasgos morfológicos. La similitud morfológica de V. jarai con V. araucanius y V. retamali, contrasta con el grado de divergencia genética que existe con estas especies. Finalmente, se utilizan los criterios de la Lista Roja de la UICN para asignar el estado de conservación “En Peligro Critico” a esta nueva especie.

Recent molecular studies demonstrate that the species Leptodactylus pallidirostris and L. validus are conspecific. Leptodactylus pallidirostris was previously considered to occupy portions of mainland South America (Venezuela, Guyana, Suriname, and French Guiana), whereas L. validus was considered to occur only on the islands of Trinidad, Tobago, and certain Lesser Antillian islands. The purpose of this paper is to summarize information for the currently understood single species Leptodactylus validus.

With more than 20 recognized species, Monodelphis is the most species-rich genus of living Didelphidae. Recent research on these opossums revealed additional species from Perú and Venezuela, and herein we describe a new species from the montane forests of the eastern slope of the central Andes in Perú. Monodelphis gardneri, new species, is a small taxon with three black dorsal stripes, more similar in external appearance and cranial features to taxa from eastern Brazil, such as M. theresa or M. americana, than to Andean species, like M. osgoodi. Phylogenetic analyses of cytochrome b gene sequences recovered this new species as closer to M. americana from eastern Brazil than to M. theresa (another species in our analyses with three black dorsal stripes). In spite of this external resemblance, the molecular phylogeny indicates that species with dorsal stripes, including M. americana, M. theresa, and the new species, do not form a monophyletic group. Although weakly supported, a relationship between M. americana and the new species suggests a biogeographic connection between these disjunct distributions, i.e., from eastern Brazil and the eastern versant of the Andes.

Constantine S. Rafinesque described Sorex dichrurus as a shrew in 1833, based on a specimen he found in a proprietary museum near Niagara Falls on the New York/Ontario border. The name subsequently has been ignored by the scientific community. By describing this specimen as a shrew and ascribing it to the genus Sorex, Rafinesque clearly indicated that his species should be considered a member of the taxonomic family now recognized as the Soricidae (Mammalia, Eulipotyphla). Yet, the description of the animal, and its comparison to “Gerbillus,” clearly identify it as a dipodid rodent, specifically Zapus hudsonius (Zimmermann, 1780); S. dichrurus should be treated as a junior subjective synonym of that taxon. Based on its type locality of Goat Island, New York, this name is also a junior synonym of the subspecies Z. hudsonius canadensis (Davies, 1798).