Two new brackish-water species of Pogaina (Rhabdocoela: Provorticidae) from China.

Two new species of the genus Pogaina Marcus, 1954 (Provorticidae), namely Pogaina sinensis n. sp. and Pogaina shenzhenensis n. sp. are described from brackish water in the intertidal zone of Shenzhen Bay. For P. sinensis n. sp., the tubular stylet is slightly curved at the distal end and a fusiform structure with a flange is present at 66% of the stylet. The flange encircles the stylet, with its ends attached to the midpoint and the distal end of the stylet. For P. shenzhenensis n. sp., the stylet has a N-shaped overall morphology. A band provided with dense needle-like structures is present at the distal end of the stylet. Both the morphological (stylet) and phylogenetic (18S rDNA and 28S rDNA) analyses support the establishment of these two new species.

Two new species of Rhabdocoela (Polycystididae and Trigonostomidae) from China.

Two new species of Rhabdocoela, namely Alcha sinensis n. sp. (Polycystididae) and Trigonostomum sinensis n. sp. (Trigonostomidae), were discovered from the intertidal zone of eastern Shenzhen City, China. For A. sinensis n. sp., the stylet consists of two symmetrical triangular plates and one lamellar plate. All three plates are jagged at their posterior ends. The anterior end of the stylet connects to a thick muscular layer, which causes its movement. For T. sinensis n. sp., the copulatory organ consists of a long-tubular stylet and two "T"-shaped plates (plate I and plate II). The stylet bends 120° at 25% of its length from the base and extends straight distally. Two "T" plates are connected to each other and surround the stylet. Plate I is hook-shaped at its distal end, and plate II has a similar length but only half the width of plate I. The phylogenetic (18S rDNA and 28S rDNA) results also support the establishment of these two new species. On the basis of the molecular phylogeny and morphology of the copulatory organ and bursa appendage, we propose a new categorization of the species of Trigonostomum.

Four new species of the genus Paraustrorhynchus (Rhabdocoela: Kalyptorhynchia: Polycystididae).

Four new species of Paraustrorhynchus (Rhabdocoela: Kalyptorhynchia: Polycystididae) are described: two from Southern China (P. shenda n. sp., P. sinensis n. sp.), one from New Caledonia (P. isoldeae n. sp.), and one from India (P. smeetsae n. sp.). All four species show a typical dark blue dorsal pigmentation pattern, which is unique to the genus. This pigment forms a broad longitudinal line in P. shenda n. sp. and P. sinensis n. sp., shows an additional transverse band at the level of the pharynx in P. smeetsae n. sp. and forms a Y-shaped pattern in P. isoldeae n. sp. The four species can also be distinguished from each other and their congeners by the detailed morphology of the hard parts of the male system, which in all cases consists of an L-shaped (P. shenda n. sp., P. isoldeae n. sp) or slightly-curved (P. smeetsae n. sp., P. sinensis n. sp.) prostate stylet type II and a prostate stylet type III, which consists of three plates: a basal plate from which two longer plates depart, each with a distal serrated rim. A phylogenetic analysis based on 18S and 28S-rDNA data indicates that Paraustrorhynchus is a monophyletic taxon within Polycystidinae, with Alcha evelinae as the sister group.

A new species and new record of Polycystididae (Rhabdocoela: Kalyptorhynchia) from China.

One new species and one newly recorded species of Polycystididae from China, Paulodora sinensis n. sp. and Polycystis ali Schockaert, 1982, were described based on comprehensive morphological and molecular analyses. In Paulodora sinensis n. sp., the stylet is double-walled and is composed of a funnel-shaped proximal part and a spiral distal part, while the outer stylet forms a minor fold proximally. In Polycystis ali Schockaert, 1982, the stylet is also double-walled with a funnel-shaped proximal part. However, the collar-shaped distal part is partially concave and forms a jagged edge. The concatenated 18S rDNA and 28S rDNA phylogenetic analysis supports the establishment of the new species. Besides, based on the morphology of stylet, we have made detailed categorization among the recorded species within these two genera.

Two new species and the molecular phylogeny of eight species of Macrostomum (Platyhelminthes: Macrostomorpha) from southern China.

Two new species of Macrostomum (Platyhelminthes: Macrostomorpha), M. shiyanensis n. sp. and M. lankouensis n. sp. are described from Shiyan Reservoir and Lankou Town. Morphological characteristics of the penis stylets and sperm, as well as the phylogenetic analysis using concatenated sequences of 18S and 28S rDNA genes support the establishment of these two new species and indicate that they are closely related to M. sinensis and M. heyuanensis described from different regions of Guangdong province. Finally, the progress of molecular phylogenetics of Macrostomum worldwide is also discussed.

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

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.