taxonID	type	description	language	source
03B387CDAC67FF98FF4CFE91FBA9FC4A.taxon	description	(Figs. 2 – 4)	en	Xin, Fan, Zhang, Si-Yu, Shi, Yong-Shi, Wang, Lei, Zhang, Yu, Wang, An-Tai (2019): Macrostomum shenda and M. spiriger, two new brackish-water species of Macrostomum (Platyhelminthes: Macrostomorpha) from China. Zootaxa 4603 (1): 105-124, DOI: 10.11646/zootaxa.4603.1.5
03B387CDAC67FF98FF4CFE91FBA9FC4A.taxon	materials_examined	Material examined. Holotype (PLA – Ma 0110): one mounted specimen. Paratypes (PLA – Ma 0111 – 112): two serially-sectioned specimens. The type specimens were collected in OCT mangrove wetland, Shenzhen City, Guangdong Province, China (22 ° 31 ′ 41 ″ N, 113 ° 59 ′ 9 ″ E) (see Fig. 1 for sampling location) from September to October, 2016. All specimens are deposited in IZCAS.	en	Xin, Fan, Zhang, Si-Yu, Shi, Yong-Shi, Wang, Lei, Zhang, Yu, Wang, An-Tai (2019): Macrostomum shenda and M. spiriger, two new brackish-water species of Macrostomum (Platyhelminthes: Macrostomorpha) from China. Zootaxa 4603 (1): 105-124, DOI: 10.11646/zootaxa.4603.1.5
03B387CDAC67FF98FF4CFE91FBA9FC4A.taxon	etymology	Etymology. The name of this new species is derived from the abbreviated Chinese name of Shenzhen University.	en	Xin, Fan, Zhang, Si-Yu, Shi, Yong-Shi, Wang, Lei, Zhang, Yu, Wang, An-Tai (2019): Macrostomum shenda and M. spiriger, two new brackish-water species of Macrostomum (Platyhelminthes: Macrostomorpha) from China. Zootaxa 4603 (1): 105-124, DOI: 10.11646/zootaxa.4603.1.5
03B387CDAC67FF98FF4CFE91FBA9FC4A.taxon	description	Description. Body flattened dorsoventrally and without pigment. The body length and width of living mature individual is 1000 ± 123 µm (n = 5) and 225 ± 30 µm (n = 5), respectively (Figs. 2 A, 4 A). The thickness of the epidermis is 5 ± 1.0 µm (n = 5), with cilia up to 4 ± 0.5 µm (n = 5) covering the entire surface. There are tufts of sensory hairs that are 10 ± 1.3 µm (n = 5) long, sparsely distributed on the body edge. The anterior end is slightly more rounded than the posterior extremity, while tufts of rigid cilia (4 ± 0.7 µm long, n = 5) are located at both the anterior and posterior ends of the body. Generally, the rigid cilia are shorter and thicker than sensory hairs. The rhabdite rods, 7 ± 1.1 µm (n = 5) long, are scattered in groups (mostly 3 – 9 rhabdites in each group) and are particularly abundant on the dorsal surface of the body. The distance between the two rounded eyes is 30 ± 4.6 µm (n = 5) (Figs. 2 A, 4 A). The mouth is 101 ± 9.2 µm (n = 5) long and the pharynx is ventrally surrounded by several pharyngeal glands (Fig. 3 A & C). The tail tapers gradually and has large amount of adhesive glands (Fig. 4 A). The paired ovoid testes, 82 ± 9.7 µm (n = 5) long, are situated ventrally between the pharynx glands and ovaries (Figs. 2 B, 4 A). The long oval-shaped false vesicula seminalis connects to the vesicula seminalis at its right side. The oval-shaped vesicula seminalis has a thickened muscular wall. The vesicula granulorum connects to the vesicula seminalis and is partially inserted into the proximal end of the penis stylet (Figs. 2 C, 3 B & E – F, 4 B – C). The narrow funnel-shaped penis stylet is 56 ± 3.1 µm (n = 5) long. It has a slightly curved end (curvature less than 15 °, the value was measured according to Ferguson 1940 a) and is gradually narrowed towards the distal beveled end (Figs. 2 D, 4 D). The proximal end of the stylet is 14 ± 3.8 µm (n = 5) in diameter, while the willow leaf shaped distal opening is 8 ± 1.0 µm (n = 5) in length (Fig. 2 D). The mature sperm are 28 ± 1.3 µm (n = 5) long when swimming (Figs. 2 E – F, 4 E). They have neither bristles nor brush, and are surrounded by an undulating membrane in the mid-body region (Fig. 2 F). The boundaries between the feeler, body and shaft of the sperm are not obvious. The paired elongated ovoid ovaries are 163 ± 14.2 µm (n = 5) long and are situated posterior to the testes on both sides of the body (Fig. 2 B). The big light-brown mature oocytes usually contain abundant yolk (Fig. 2 A). The female antrum is located posterior to the gut on ventral side. Besides, there are numerous cement glands surrounding the female gonopore (Fig. 3 A & D).	en	Xin, Fan, Zhang, Si-Yu, Shi, Yong-Shi, Wang, Lei, Zhang, Yu, Wang, An-Tai (2019): Macrostomum shenda and M. spiriger, two new brackish-water species of Macrostomum (Platyhelminthes: Macrostomorpha) from China. Zootaxa 4603 (1): 105-124, DOI: 10.11646/zootaxa.4603.1.5
03B387CDAC67FF98FF4CFE91FBA9FC4A.taxon	discussion	Remarks. A comparison of the penis stylets of Macrostomum shenda n. sp. and six similar species within the genus is shown in Table 4. They all have a funnel-shaped stylet with an oblique and non-thickening terminal opening. However, in M. ensiferum, M. phillipsi and M. sinyaense, the ratios of the proximal diameter to the stylet length are less than 16 %, while the corresponding value of M. shenda n. sp. is around 25 %. Besides, in M. ensiferum, the bending angle of the stylet (> 30 °) is larger than that of M. shenda n. sp. (<15 °, the values were measured according to Ferguson 1940 a). Another similar species, namely M. sinyaense, has a “ Verschlussapparat (Young 1976, and named “ cellular valve ” in Ladurner et al. 2005) ”, but this structure is absent in M. shenda n. sp.. Moreover, the stylet of M. obtusum (80 – 91 µm, Luther 1960) is longer than that of M. shenda n. sp. (56 µm) and bends around 65 ° (Papi 1951). As for M. vejdovskyi, the stylet length (35 µm) and proximal end diameter (9 µm) of the stylet are obviously shorter than those of M. shenda n. sp. (56 µm and 14 µm). In addition, the sperm of M. vejdovskyi and M. phillipsi have bristles, while this structure is absent in M. shenda n. sp..	en	Xin, Fan, Zhang, Si-Yu, Shi, Yong-Shi, Wang, Lei, Zhang, Yu, Wang, An-Tai (2019): Macrostomum shenda and M. spiriger, two new brackish-water species of Macrostomum (Platyhelminthes: Macrostomorpha) from China. Zootaxa 4603 (1): 105-124, DOI: 10.11646/zootaxa.4603.1.5
03B387CDAC6AFF9EFF4CFC0DFA96FF17.taxon	description	(Figs. 5 – 7)	en	Xin, Fan, Zhang, Si-Yu, Shi, Yong-Shi, Wang, Lei, Zhang, Yu, Wang, An-Tai (2019): Macrostomum shenda and M. spiriger, two new brackish-water species of Macrostomum (Platyhelminthes: Macrostomorpha) from China. Zootaxa 4603 (1): 105-124, DOI: 10.11646/zootaxa.4603.1.5
03B387CDAC6AFF9EFF4CFC0DFA96FF17.taxon	materials_examined	Material examined. Holotype (PLA – Ma 0100): one mounted specimen. Paratypes (PLA – Ma 0101 – 104): four serially-sectioned specimens. The type specimens were collected from Waterlands Resort, Shenzhen City, Guangdong Province, China (22 ° 42 ′ 39 ″ N, 113 ° 46 ′ 48 ″ E) (see Fig. 1 for sampling location) in March, 2017. All specimens are deposited in IZCAS.	en	Xin, Fan, Zhang, Si-Yu, Shi, Yong-Shi, Wang, Lei, Zhang, Yu, Wang, An-Tai (2019): Macrostomum shenda and M. spiriger, two new brackish-water species of Macrostomum (Platyhelminthes: Macrostomorpha) from China. Zootaxa 4603 (1): 105-124, DOI: 10.11646/zootaxa.4603.1.5
03B387CDAC6AFF9EFF4CFC0DFA96FF17.taxon	etymology	Etymology. The name of this new species is derived from the morphology of its spiral-shaped penis stylet.	en	Xin, Fan, Zhang, Si-Yu, Shi, Yong-Shi, Wang, Lei, Zhang, Yu, Wang, An-Tai (2019): Macrostomum shenda and M. spiriger, two new brackish-water species of Macrostomum (Platyhelminthes: Macrostomorpha) from China. Zootaxa 4603 (1): 105-124, DOI: 10.11646/zootaxa.4603.1.5
03B387CDAC6AFF9EFF4CFC0DFA96FF17.taxon	description	Description. The body is dorsoventrally flattened and the dorsal epidermis is covered by an irregular mesh of black pigments in different densities (particularly dense around the eyes). The tail is bifurcated (Figs. 5 A – B, 7 A – B). The living mature individual is 1324 ± 104 µm (n = 5) in length and 368 ± 37 µm (n = 5) in width. The epidermal thickness varies up to 6 ± 1.2 µm with cilia up to 7 ± 1.0 µm (n = 5). The rigid cilia, 8 ± 2.1 µm (n = 5) in length, are present at both ends of the body. The sensory hairs are 24 ± 5.2 µm (n = 5) long. The rhabdite rods, 20 ± 2.0 µm (n = 5) long, are scattered in groups (mostly 1 – 3 rhabdites in each group) all over the body surface, and are particularly abundant on the dorsal surface. The distance between the two eyes is 43 ± 7.4 µm (n = 5) (Fig. 5 A – B). The mouth is 106 ± 19.8 µm (n = 5) in length. The pharynx is located posterior to the eyes and is surrounded by gland cells (Fig. 7 A). The tail region is abundant in adhesive glands (Fig. 5 C). The paired testes, 266 ± 35.9 µm in length (n = 5), are highly lobulate and generally contain 5 to 6 lobes on each side (Figs. 5 B, 6 E, 7 A). The false vesicula seminalis lies posterior to the female antrum and connects to the vesicula seminalis. The vesicula seminalis connects to the spindle-shaped vesicula granulorum via a short duct, while a small part of the vesicula granulorum is enclosed by the proximal end of the stylet (Figs. 5 D, 6 A & F – H, 7 C – D). Both the vesicula seminalis and vesicula granulorum have a thick muscular wall. The penis stylet, 270 ± 22.5 µm (n = 5) in length, is spirally twisted. The straight line (marked as ‘ a’) between the proximal and distal ends of the stylet is 184 ± 13.5 µm (n = 5) (Figs. 5 F – G, 7 D – E). The diameter of the proximal end is 16 ± 2.0 µm (n = 5). The distal opening is 3 ± 0.7 µm (n = 5) in diameter and is bulbous with an asymmetrical thickening (Figs. 5 H, 7 E – F). Mature sperm are 72 ± 3.6 µm long (n = 5) when swimming (Figs. 5 I – J, 7 G). A pair of bristles, 10 ± 0.6 µm (n = 5) long, lies on the sperm body. The extensions of the brush are 2 ± 0.3 µm (n = 5) long. The lengths of the feeler, body and shaft of the sperm are 14 ± 2.1 (n = 5), 13 ± 1.3 (n = 5) and 46 ± 2.3 µm (n = 5), respectively. The female reproductive system consists of a pair of ovaries, a seminal bursa, a bursal pore, a female antrum and a female gonopore. A pair of indented ovaries, 110 ± 23.1 µm (n = 5) long, is located posterior to the testes on both sides. The ovoid seminal bursa, 87 ± 10.5 µm (n = 5) long, is located posterior to the left side of the intestine (Figs. 5 B, 7 A). The seminal bursa has a thickened muscular wall, and contains plenty of received sperm. It opens anteroventrally to the outside and connects to female antrum via a short, narrow duct (Figs. 5 D – E, 6 B – D). The female antrum is surrounded by a numerous of cement glands.	en	Xin, Fan, Zhang, Si-Yu, Shi, Yong-Shi, Wang, Lei, Zhang, Yu, Wang, An-Tai (2019): Macrostomum shenda and M. spiriger, two new brackish-water species of Macrostomum (Platyhelminthes: Macrostomorpha) from China. Zootaxa 4603 (1): 105-124, DOI: 10.11646/zootaxa.4603.1.5
03B387CDAC6AFF9EFF4CFC0DFA96FF17.taxon	discussion	Remarks. According to Ferguson (1954), in Macrostomidae, only two genera possess two openings to the exterior in their female reproductive system, one is the genus previously named Axia and the other is the genus Promacrostomum. The major difference between these two genera is that Axia lacks the structure “ ductus-genitointestinalis (An-der-Lan 1939) ”, which is present in the genus Promacrostomum. For this reason, species Macrostomum gieysztori Ferguson, 1939 had been moved to Axia by Ferguson (1954) and was the only species in this genus. However, since the generic name Axia had not been accepted in the literature, Sluys (1986) suggested to assign species gieysztori to the genus Promacrostomum. Moreover, Schärer et al. (2011) noted that the generic name Axia had been occupied by a genus of Lepidoptera since 1821. Based on molecular phylogenetic analysis, Schärer et al. (2011) suggested to reinstate M. gieysztori to the genus Macrostomum. The female reproductive system of M. spiriger n. sp. is similar to M. gieysztori in that they both have two exterior openings (female gonopore and bursal pore) and lack “ ductus-genito-intestinalis ”. M. spiriger n. sp. also clusters within the genus Macrostomum in 18 S and 28 S rDNA molecular phylogenetic analyses (Figs. 8 – 11), therefore, we classified M. spiriger n. sp. into Macrostomum. In summary, the stylet of M. spiriger n. sp. is spirally twisted with six bends (b 1 – b 6, Fig. 7 E), which is a unique morphological characteristic within the genus Macrostomum, and this species has a seminal bursa located anterior to the female gonopore. As such, it is evident that M. spiriger n. sp. is a new species within Macrostomum. Molecular phylogenetic analysis. The phylogenetic trees generated from single gene (18 S and 28 S rDNA, respectively) by Maximum Likelihood (ML) and Bayesian-inference (BI) methods are shown in Figs. 8 – 11. The 28 S rDNA results indicated that the three specimens of the new species cluster together respectively, forming a well-supported clade with other species within the genus Macrostomum. Although these two species are clearly separated by their 28 S rDNA sequences and morphological characters, M. shenda n. sp. cannot be well-separated based on 18 S rDNA analyses. Similar situation can also be found in other species of the genus, including M. tuba and M. quiritium (Figs. 8, 9). As such, both the 28 S rDNA phylogenetic and morphological evidence supports the establishments of M. shenda n. sp. and M. spiriger n. sp. as new species within the genus Macrostomum.	en	Xin, Fan, Zhang, Si-Yu, Shi, Yong-Shi, Wang, Lei, Zhang, Yu, Wang, An-Tai (2019): Macrostomum shenda and M. spiriger, two new brackish-water species of Macrostomum (Platyhelminthes: Macrostomorpha) from China. Zootaxa 4603 (1): 105-124, DOI: 10.11646/zootaxa.4603.1.5
