Two new species of Kalyptorhynchia (Koinocystididae and Gnathorhynchidae) from China

Abstract

Two new species of Kalyptorhynchia (Rhabdocoela), namely Itaipusa sinensis n. sp. (Koinocystididae) and Prognathorhynchus sinensis n. sp. (Gnathorhynchidae) were described from brackish water near Shenzhen Bay, representing the first records of Koinocystididae and Gnathorhynchidae in China. For I. sinensis n. sp., the U-shaped cirrus contains 50 triangular lamellar spines, with two cuticular (pseudocuticular) hooks situated at both sides of its anterior part. The hook I (right side) is funnel-shaped, while the hook II (left side) is triangular lamellar in shape. For P. sinensis n. sp., the proboscis hook has two hooks situated in an anterior to posterior sequence. The semicircular tubular stylet has a hollow spherical dead end posteriorly to the distal opening. Both the morphological and phylogenetic (18S rDNA and 28S rDNA) analyses support the establishment of these two new species.

Taxonomy and phylogeny of Koinocystididae (Platyhelminthes, Kalyptorhynchia), with the description of three new genera and twelve new species

“…To this date, the family Koinocystididae has largely been neglected in molecular phylogenetic studies. Indeed, only a small fraction (< 5%) of the known species was included in the analyses by Tessens et al (2014), Smith et al (2015, and Lin et al (2017). Due to this poor taxon coverage, the interspecific relationships within Koinocystididae remain elusive to this day.…”

“…= sword, which refers the presence of the stylet within the copulatory bulb) (urn:lsid:zoobank.org:act:1D672D44-5695-416E-A24D-B2F25BCCD80B). Both Koinogladius sinensis (Wang & Lin in Lin et al, 2017) comb. n. and R. dillonicus have the testes at midbody, caudally from the pharynx.…”

“…(1) Mesorhynchus terminostylis, (2) a clade with the two species of Utelga, and (3) a clade comprising all other included koinocystidids. Within the latter clade, another polytomy is retrieved, consisting of three clades each of which containing species that were considered to belong to Itaipusa: (1) clade 'sinensis' including Rhinolasius dillonicus and Koinogladius sinensis (Wang & Lin, 2017)…”

“…Afterward, he considered it a separate family (Meixner, 1925), at that moment including three species: Koinocystis sophiae Graff (1905) [now Itaipusa sophiae (Graff, 1905) Karling, 1978], K. neocomensis (Fuhrmann, 1904) Meixner, 1924and Anoplorhynchus piger Meixner, 1925[= Sekerana stolzi (Sekera, 1912 Strand, 1914; see Karling 1980]. Since then many new species and genera have been described, and the taxonomy was discussed and refined by several authors: Marcus (1949Marcus ( , 1951Marcus ( , 1954, Karling (1952aKarling ( , 1952bKarling ( , 1954Karling ( , 1964Karling ( , 1978Karling ( , 1980, Brunet (1972), Reygel et al (2011), Willems et al (2017), and Lin et al (2017). Currently, Koinocystididae includes 24 accepted genera and 51 accepted species (Tyler et al 2006(Tyler et al -2020.…”

“…In the most recent exhaustive phylogenetic analysis of Kalyptorhynchia (Tessens et al 2014), only four koinocystidid species, two of which were undescribed species of Itaipusa Marcus, 1954, were included, representing less than 5% of the known diversity of Koinocystididae. More recently, Lin et al (2017) described a new species of Itaipusa from China and discussed its relationships with the latter two undescribed species. Koinocystididae and Itaipusa were provisionally recovered as clades in these studies, but corroboration based on a more extensive dataset is needed.…”