Pycnophyidae (Kinorhyncha: Allomalorhagida) from the Gulf of Mexico: Fujuriphyes viserioni sp. nov. and a redescription of Leiocanthus langi (Higgins, 1964), with notes on its intraspecific variation

New record of the soft-bodied genus Franciscideres (Kinorhyncha) from Argentina, with notes on its movement and morphological variation

“…The observed morphological differences of the animals collected in Argentina are interpreted as morphological variation or may have been overlooked in the Brazilian specimens. Recent articles found that intraspecific variation may be considerably larger in Kinorhyncha than previously assumed and our results seem to support these observations (Neuhaus & Sørensen 2013;Neuhaus et al 2014Neuhaus et al , 2019Neuhaus & Kegel 2015;Sánchez et al 2019;.…”

“…Several other characters observed in the Argentinian specimens were not described for the Brazilian material, but we cannot rule out that they are present also in these populations, viz, (1) presence of ventrolateral tubes on segment 1, (2) introvert features, (3) each segment composed of a closed cuticular ring, (4) trunk cuticle ornamented by a secondary fringe of knob-like structures, (5) ventral free flap of segment 10 terminating in two lateral and one broad triangular lobes, (6) ventral free flap of segment 11 centrally terminating in four lobes, ( 7) lateral terminal spines armed with thorn-like processes, (8) pores/sensory spots/glands distribution and ( 9) sexual dimorphism in segments 10 and 11 (Tables 4, 5). In addition, some of the differences noted (Tables 4, 5) are probably compatible with the amount of species-specific variation now recognized in other Kinorhyncha species (Neuhaus & Sørensen 2013;Neuhaus et al 2014Neuhaus et al , 2019Neuhaus & Kegel 2015;Sánchez et al 2019;.…”

“…The first aim of this article is to describe the morphology of an unusual kinorhynch with a thin body cuticle, collected from a sandy beach at Monte Hermoso (Buenos Aires Province, Argentina). Our material showed the characters defining the monotypical genus Franciscideres Dal Zotto et al, 2013. The specific identification faces the taxonomical conflict arising from the insufficiency of the original information about the type species and the recent evidence that Kinorhyncha species can show a considerably larger intraspecific variability than previously assumed (Neuhaus & Sørensen 2013;Neuhaus & Kegel 2015;Neuhaus et al 2014Neuhaus et al , 2019Sánchez et al 2019;. Though intraspecific variation was rarely thought to be important for the taxonomy of kinorhynchs (Sørensen & Pardos 2008;Dal Zotto et al 2013;Neuhaus 2013;Yamasaki 2016Yamasaki , 2017, the huge variation described for some species (e.g., Neuhaus et al 2019;Sánchez et al 2019) highlights a change of mind and emphasizes the need of paying attention to such variation.…”