Disentangling cryptic species in Parastenocarididae (Copepoda: Harpacticoida) with an integrative approach: the case of Stammericaris similior sp. nov. and Stammericaris destillans Bruno & Cottarelli 2017.

Stammericaris similior sp. nov. is described combining light microscopy, scanning electron microscopy, and genetic barcoding. The new species was collected from rimstone pools in Scrivilleri Cave, a cave in Sicily with so far unexplored microcrustacean fauna. The new species is particularly interesting because it is morphologically very similar to Stammericaris destillans, an epikarstic parastenocaridid endemic to a different Sicilian cave; however, the phylogenetic analysis based on the mitochondrial COI gene of sixteen parastenocaridids shows that these two Stammericaris are two distinct species, with an uncorrected p-distance of 22.9, and the sequences of Stammericaris similior sp. nov. cluster together in a well-supported monophyletic clade, with two different haplotypes. To our knowledge, the presence of different species of almost identical morphology had not been recorded before for the genus Stammericaris. The integrated molecular and morphological analysis, the latter conducted with the support of SEM, allows disentangling the affinities of the new species and identifying a few distinctive characters: the males of the new species are characterized by the caudal rami shorter than the anal somite; the morphology of the P3, which is thin and slightly arched, with three proximal spinules on exp-1; the peculiar structure of the P4 enp; the P4 basis ornamented with two spinules of different length, the one closest to the endopod being the shortest one, and a half-moon shaped lamella. The new species differs from S. destillans for its larger size, the presence of: three spinules, instead of two, on the P3 exp-1; the half-moon shaped lamella on the P4 basis; a row of spinules along the inner margin of P4 exp-1. We also provide data on the ecology and distribution of the new species, a list of the other copepod species collected, and a dichotomic key for the males of all species presently assigned to the genus.

The genus Stammericaris Jakobi (Copepoda: Harpacticoida: Parastenocarididae) in the Nearctic subregion: description of Stammericaris remotaepatriae sp. nov., proposal of Stammericaris palmerae (Reid 1992) comb. nov., and remarks on other North American Parastenocarididae.

We describe a new harpacticoid, Stammericaris remotaepatriae sp. nov., collected from the hyporheic habitat of a stream in Nantucket, MA, USA. The new species is characterized by the size of the caudal rami of both sexes, which are shorter than the anal somite, by the morphology and armature of the P3 and, mainly, by the P4 endopod of males, represented by a curved plate with a strongly bifid tip, the distal proximal outgrowth of the distal margin spiniform and denticled, the proximal outgrowth missing. The study of the new species allowed us to review the systematic position of Parastenocaris palmerae Reid, 1992, which we transferred to Stammericaris Jakobi, 1972 as Stammericaris palmerae (Reid, 1992) comb. nov., based mainly on the structure of the male P4 endopod complex and the setation of the caudal rami. We also discussed the taxonomic position and affinities of Parastenocaris trichelata Reid, 1955, suggesting that this species is related to the two former ones for a set of diagnostic features, but can not be attributed to the genus due to the peculiar morphology of the male P4 endopod complex; P. trichelata is therefore considered species inquirenda. We also discussed Parastenocaris sp. 1 and Parastenocaris sp. 3, two taxa only partially described and drawn in Strayer (1988). In fact, Parastenocaris sp. 1 can be related to Stammericaris and might represent a third species of the genus in the Nearctic region. Remarkably, the structure of the male P4 endopod of Parastenocaris sp. 3 is typical of Proserpinicaris Jakobi, 1972; this hypothetical assignment of the species to Proserpinicaris, if confirmed, would be of relevant taxonomic and biogeographic value. Finally, we provide an updated distribution map of the genus Stammericaris and brief remarks on the faunistic and ecological characteristics of the taxa presented and discussed in this paper.

Interesting interstitial Paramesochridae (Copepoda: Harpacticoida): Maliithipon wellsi gen. et sp. nov. from the Philippines, M. aberrans (Mielke, 1984) comb. nov. from Panama, and M. cf. aberrans (Mielke, 1984) from the Azores.

We propose and describe a new genus of interstitial Paramesochridae, Maliithipon gen. nov., to accommodate three species. Maliithipon wellsi sp. nov., type species of the genus, is described based on specimens collected in two sandy beaches in Isla Verde, the Philippines. Apodopsyllus aberrans Mielke, 1984a described from Panama, is allocated to the herein erected genus as Maliithipon aberrans (Mielke, 1984a) comb. nov. Maliithipon cf. aberrans is described, based on specimens collected in the Azores and previously identified as Apodopsyllus aberrans. The new genus is characterized by several distinct morphological features: mandible with uniramous, 2-segmented palp and gnathobase with thin and pointed teeth; maxillule with reduced armature, lacking endopod and exopod; maxilla large, with three syncoxal endites and endopod with reduced setal number; P5 very reduced in both sexes; caudal rami with six setae, two of which (setae III and VI) transformed; pseudoperculum well-developed, with four-lobed distal margin. The new genus is included in the subfamily Paramesochrinae Lang, 1944 and in the genus-group Scottopsyllus (sensu Huys, 1987). It has strong affinities with Leptopsyllus (Leptopsyllus) platyspinosus Mielke, 1984b and Wellsopsyllus (Intermediopsyllus) smirnovi (Kunz, 1992), which are considered as species inquirendae in this paper. Some remarks on the ecology and geonemy of the three studied species are provided. We also list the accompanying Paramesochridae obtained from the two new collecting sites of the genus, and all the genera of Paramesochridae recorded from other sites in the Philippines during the same survey.

Morphological and molecular analyses of epikarstic Parastenocarididae (Copepoda: Harpacticoida) from two Sicilian caves, with description of a new Stammericaris.

We describe Stammericaris destillans sp. nov., and re-describe Stammericaris trinacriae (Pesce, Galassi and Cottarelli 1988) based on new material. The two species were collected from epikarstic drips and pools on the floor of two different caves: a karstic (Molara Cave) and a gypsum (Entella Cave) cave, respectively, both located in Sicily, Italy. We also report the presence of previously undescribed structures for Stammericaris amyclaea (Cottarelli 1969) and Stammericaris orcina (Chappuis 1938). Phylogenetic analyses of the mitochondrial COI and ribosomal 18S genes attributed the new species to Stammericaris Jakobi 1972, therefore the structure of the male P4 endopod of S. destillans is interpreted as an autapomorphy; other morphological features (structure of male antennule and P3, of female P3; inner ornamentation of P1 basis, armature of caudal rami and shape and armature of P5 of both sexes) correspond to those typical of the genus. Hence, we slithgly amended the generic diagnosis. [zoobank.org:pub:4CC84A0C-C511-4388-9728-41647E58097A].