Four new species of <i>Pycnophyes</i> (Kinorhyncha: Homalorhagida) from Korea and the East China Sea

Abstract

SUMMARY: Four new species of Pycnophyes are described from Korean waters and the East China Sea. Pycnophyes pardosi n. sp. is distinguished from other congeners by the presence of a single paradorsal seta on segments 2-8 and a pair on segment 9, combined with the presence of longitudinal cuticular thickenings on the dorsal and ventral sides of segment 10. Pycnophyes chalgap n. sp. is easily distinguished by the shape of its midsternal plate with the rounded posterior margin, extending beyond and overlapping half of the following segment. Pycnophyes cristatus n. sp. is recognized by its lack of ventromedial setae on segments 3-6 combined with the presence of pointed middorsal processes that turn progressively longer towards the posterior segments from segment 6. The process on segment 10 is conspicuously long, extending beyond the posterior margin of segment 11. Pycnophyes smaug n. sp. is distinguished by its general scarcity of setae which, with the exception of those in lateroventral positions, only appear in laterodorsal positions on segments 2 and 9 and in ventromedial position on segment 9. The description of four additional species brings the total number of valid kinorhynch species around the Korean Peninsula up to 26.Keywords: biodiversity, meiofauna, Pycnophyidae, morphology, taxonomy, Korean Peninsula. RESUMEN: Cuatro nuevas espeCies de PycnoPhyes (KinorhynCha: homalorhagida) de Corea y el mar del este de China. -Se describen cuatro nuevas especies de aguas coreanas y del este del mar de China. Pycnophyes pardosi n. sp. se distingue de las demás especies por la presencia de una única seda paradorsal en los segmentos 2-8 y un par en el segmento 9, combinado con la presencia de engrosamientos cuticulares longitudinales en el lado dorsal y ventral del segmento 10. Pycnophyes chalgap n. sp. es fácilmente distinguible por la forma de su placa medioesternal con el margen posterior redondeado, sobrepasando y solapando la mitad anterior del siguiente segmento. Pycnophyes cristatus n. sp. es reconocible por la ausencia de sedas ventromediales en los segmentos 3-6 combinado con la presencia de salientes mediodorsales puntiagudos que a partir del segmento 6 se vuelven progresivamente más largos hacia los segmentos posteriores. El saliente del segmento 10 es llamativamente largo, extendiéndose más allá del margen posterior del segmento 11. Pycnophyes smaug n. sp. se distingue por su carencia general de sedas que, aparte de las lateroventrales, solo aparecen en posición laterodorsal en los segmentos 2 y 9, y en posición ventromedial en el segmento 9. La descripción de las cuatro especies aumenta hasta 26 el número total de especies válidas de kinorrincos entorno a la península coreana.

Deep-sea Kinorhyncha: two new species from the Guinea Basin, with evaluation of an unusual male feature

“…Terminology related to seta distribution for homalorhagids follows the standardization criteria established by Sánchez et al (2011) and adopted by all authors (Herranz et al 2014;Sánchez et al 2013Sánchez et al , 2014aSørensen et al 2010;Yamasaki et al 2012), except Neuhaus (2013.…”

“…The longest ones are those of segments 9 and 10, exceeding the first third of segment 10 and extending over the terminal trunk segment, respectively. Seven other species in the genus have similar middorsal processes progressively increasing in lengths towards the posterior segments: Pycnophyes arctous Adrianov, 1999; Pycnophyes carinatus Zelinka, 1928;Pycnophyes chilensis Lang, 1953; Pycnophyes chukchiensis Higgins, 1991; Pycnophyes cristatus Sánchez et al, 2013;Pycnophyes furugelmi Adrianov, 1999;andPycnophyes odhneri Lang, 1949 (see Adrianov andMalakhov 1999;Higgins 1991;Lang 1949Lang , 1953Sánchez et al 2013;Zelinka 1928). However, only four of these species possess a middorsal process on segment 10 conspicuously extending over the last trunk segment: P. arctous, P. chukchiensis, P. cristatus, and P. furugelmi (see Adrianov and Malakhov 1999;Higgins 1991;Sánchez et al 2013).…”

“…Among the homalorhagid genera, Pycnophyes is the most species-rich so far, with 54 described species (Neuhaus 2013;Sánchez et al 2013Sánchez et al , 2014aSørensen 2013). Pycnophyes species are characterized by having one tergal and three sternal plates on segment 1, one tergal and two sternal plates on segments 2-11, and one pair of lateral terminal spines on segment 11 (Higgins 1983;Sørensen and Pardos 2008;Zelinka 1928).…”

A new kinorhynch genus, Mixtophyes (Kinorhyncha: Homalorhagida), from the Guinea Basin deep-sea, with new data on the family Neocentrophyidae

“…Terminology related to cuticular feature distribution for homalorhagids follows the standardization criteria established by Sánchez et al (2011) and adopted by most authors (Sánchez et al 2013(Sánchez et al , 2014Yamasaki et al 2012), except Neuhaus (2013).…”

“…nov., which again is a trait shared with species of Neocentrophyes and Paracentrophyes (Higgins 1969(Higgins , 1983present contribution). Contrarily, most Pycnophyes and Kinorhynchus species have one or several secondary pectinate fringes that usually appear very conspicuous at SEM (Higgins 1983;Sánchez et al 2011Sánchez et al , 2013Sánchez et al , 2014.…”