Gieysztoria huizhouensis Zhang, Wu & Wang, 2014

Zhang, Hang, Li, Yi-Kui, Wu, Cheng-Chen & Wang, An-Tai, 2014, Two new species of the genus Gieysztoria (Rhabdocoela: Dalyelliidae) from China, Zoological Systematics 39 (4), pp. 485-495 : 489-491

3.2 Gieysztoria huizhouensis Zhang, Wu & Wang , sp. nov. ( Figs 9–14 )

Material examined. Holotype PLA-G0111 , tributary of Dongjiang River , Huizhou, Guangdong Province (23°10'57"N, 116°28'18"E) , the water temperature 25°C ( Fig. 17 ), 20 July 2014, coll. Hang Zhang. Overall sheeting, H. E. method stained. Paratypes. PLA-G0112 – PLA-G0117 , the same data as holotype ( PLA-G0112 – PLA-G0113 , mounting specimens; PLA-G0114 – PLA-G0117 , separated sclerotic mating spines). All the types were deposited in National Zoological Museum , Institute of Zoology, Chinese Academy of Sciences ( IZCAS), Beijing, China .

Description. Mature individual about 1 000–1 100 μ m in length, and middle part of body up to 220–280 μ m in width. Animal has typical body characteristics of Dalyelliidae . Whole body appears a flat-oval shape, with blunt head, cylindrical-shaped middle part of body, and V-shaped tapering tail epidermis densely covered with ciliums. Dorsally, brown irregular-oval stripes longitudinally distributed from back of its eyes to front area of eggs, with light-colored stripes on pharynx ( Fig. 9 ). Pair of eyes located in anterior end, oval-shaped eyespots formed by many melanin balls. Distance between eyes about 58 μ m. Cerebral ganglions distribute under eyes. Barrel-shaped pharynx behind eyes looks 234 μ m × 184 μ m, accounting for 1/5 of whole body length. Posterior end of pharynx joints a pocket-shaped intestinal canal, no anus present, with distinct pharyngeal glands in junction ( Figs 9–11 ).

Reproductive system. Hermaphrodite, with a gonopore. Female reproductive system consists of ovary, oviduct, uterus, seminal receptacle, vitellaria, bursa copulatrix, genital atrium and gonopore. Irregular-oval-shaped ovary lies in posterior end of intestine dorsally, which ends to a short oviduct, linking seminal receptacle and uterus. Seminal receptacle filled with spherical-shaped sperms. Within uterus usually exists a oval egg (149 μ m×100 μ m) appearing brownish red when mature ( Fig. 9 ). Two rodlike vitellaria, 466 μ m in length locate in bilateral sides of intestinal canals. Vitelline ducts from left and right side join and convert together, then extending to uterus. Other end of uterus connected to genital atrium. Utricle-shaped bursa copulatrix, formed by musclar tissues, opens holes from genital atrium ( Figs 11–12 ).

Male reproductive system consists of testes, vas deferens, a vesicula seminalis, a vesicula granulorum, prostate tissue and a sclerotic stylet. Pair of oval-shaped testes lie in ventral side at posterior end of intestinal canal. Vas deferens exists at each end of testis, then flows into vesicuta seminalis. Vesicuta seminalis filled with sperms and covered with thick circular muscles. Vesicula granulorum located between vas deferens and sclerotic stylet, which comprises eosinophilic granules inside, outside lies prostate cells. ( Figs 11–12 ). Sclerotic stylet appears typical Falcatae characteristics with 88 μ m long. Two fiber sclerotic stalks at front end about 15 μ m and 28 μ m. Base of stylet connected through stylet cross-connection, forming irregular H-shape. Cross-connection (27 μ m long, 12 μ m wide) stretches backwards along with 2 stalks, which form 6 abnormal spines namely s1, s2, s3, s6, s7 and s8. Outspread parts of cross-connection and short stalk posterior form.infundibulate-shaped S1, with 35 μ m in length, wide base and tapering distal end. Short stalk posterior stretches out s2 and s8. Length of s2 about 65 μ m. Half of part, close to the base, relatively thick, with an oval musclar layer, distal end in canine shape. S8 about 58 μ m, saber-shaped, with tip bended slightly. Outspread part of the long stalk posterior forms s3, s6 and s7. Length of s3 about 60 μ m, with strip-shaped base 10 μ m. Half of near end present a musclar layer. Daggershaped far end slightly bended. Inner edge of long stalk extends oval-plate-shaped s6, which stretches out 8 super thin flake-like spines towards the middle part. Each spine looks like a spoon and posterior edge of it has thin serrate spines. Stretching out from inner side of base of long stalk, s7 locates between s1 and s6, about 36 μ m ( Figs 13–14 ).

Etymology. The specific name refers to the type locality, Huizhou City, Guangdong Province, China.

Discussion. The new species should belong to Gieysztoria, Inaequales, Falcatae. For the subgroup Falcatae, ten species have been recorded: G. kolasai , G. saganae , G. ashokae , G. zuluensis , G. garudae , G. thienemanni , G. okugawai , G. stokesi , G. wuyishanensis and G. ramayana ( Reisinger, 1933; Ruebush & Hayes, 1939; Young, 1977; Van Steenkiste et al., 2012; Lai et al., 2013). Among these species, G. kolasai and G. saganae have original sclerotic stylet. G. ashokae and G. zuluensis have only one stylet stalk. G. garudae has stylet with obvious sawtooth on coarse spines of s3 and the surface edges of s4. G. thienemanni has s 6 in a strip-type shape. G. okugawai has 5 coarse spines, s2 fine S-shape, and s6 with 11 small spines. G. stokesi and G. wuyishanensis , which are very similar to the new species, have discoid spines and hook spines. However, G. stokesi has s7 and s8 absent and G. wuyishanensis has s8 absent. The bending angle of s 2 in both species is significantly hook-like and the discoid spine is smooth.

In G. huizhouensis Zhang, Wu & Wang , sp. nov., s2 is slightly blended and sawtooth serrations lie at its posterior of discoid spine. These are significant different from other species. The sclerotic stylet of G. ramayana is the most similar to the new species. Its full length of sclerotic stylet is 85 μ m, and the far end has 5 coarse spines, namely s1, s2, s3, s6 and s8. While in G. huizhouensis sp. nov., the full length of the stylet is 88 μ m, and 6 coarse spines are present, namely s1, s2, s3, s6, s7 and s8.

Figures

Figs 9–12. Gieysztoria huizhouensis Zhang, Wu & Wang, sp. nov. 9–10. Alive individual. 11. Whole specimen. 12. Copulatory apparatus. Scale bars: 9–11=200 μm, 12 =100 μm.

Figs 13–14. Gieysztoria huizhouensis Zhang, Wu & Wang, sp. nov., stylet. Scale bars=20μm.

Fig. 17. Distribution of Gieysztoria spp.