taxonID	type	description	language	source
BE47E558FFDAFFE65ED5CC8DFBC7F3F4.taxon	materials_examined	Material examined. Holotype: complete specimen (CPICML POH – 37 – 002), Palmitas E 2 B 1, 16 ° 49.420 ’ N and 99 ° 54.733 ’ W, 25 May 2006, 10.5 m, coarse sand Paratypes: 8 specimens (CPICML POP – 37 – 003), Palmitas E 2 B 1, 16 ° 49.420 ’ N and 99 ° 54.733 ’ W, 25 May 2006, 10.5 m, coarse sand. 6 specimens (MNCN 16.01 / 13262), Palmitas E 2 B 1, 16 ° 49.420 ’ N and 99 ° 54.733 ’ W, 25 May 2006, 10.5 m, coarse sand. 6 specimens (LACM-AHF POLY 2639) Palmitas E 2 B 1, 16 ° 49.420 ’ N and 99 ° 54.733 ’ W, 25 May 2006, 10.5 m, coarse sand. 6 specimens (AM: W. 37086), Palmitas E 2 B 2, 16 ° 49.420 ’ N and 99 ° 54.733 ’ W, 25 May 2006, 10.5 m, coarse sand. Additional material. 2 specimens (CPICML PO – 37 – 079), Palmitas E 2 B 2, 16 ° 49.420 ’ N and 99 ° 54.733 ’ W, 25 May 2006, 10.5 m, coarse sand. 2 specimens (CPICML PO- 37 - 079), El Jardín E 3 B 1, 16 ° 49.436 ’ N and 99 ° 54.981 ’ W, 26 May 2006, 12 m, coarse sand. Comparative material examined. Plakosyllis brevipes. 4 specimens (MNCN 16.01 / 6605). Spain: Mediterranean Sea, Balearic Is, Cabo Nati, NW of Menorca, 40 ° 43´10 ” N, 03 ° 49´28 ” E, 31 m. Plakosyllis quadrioculata, permanent microscope slide (MNCN 16.01 / 6605). Cuba: Cayo Matías.	en	Salcedo, Diana L., Martín, Guillermo San, Solís-Weiss, Vivianne (2011): Two new species of Syllidae (Annelida: Polychaeta) from the Southern Mexican Pacific. Zootaxa 2800: 41-52, DOI: 10.5281/zenodo.201624
BE47E558FFDAFFE65ED5CC8DFBC7F3F4.taxon	description	Description. Holotype complete specimen 2.8 mm long, 0.3 mm wide, with 54 chaetigers. Longest specimen 4.37 mm long, 0.32 mm wide, with 61 chaetigers. Body small, strongly flattened, oval, elongated, yellowish when preserved. Prostomium wider than long, trapezoidal, with two pairs of eyes, anterior one in dorsal position and posterior one in ventral position, and one pair of small ventral eyespots, (Figs. 1 A); in a few paratypes eyespots missing or only one present on either side. Antennae globular, lateral pair slightly smaller than median antenna, all arising anteroventrally, partially or totally covered by prostomium (Figs. 1 A, 1 D, 2 B). Palps round to ovate, ventral, not visible dorsally, separated but very close to each other (Figs. 1 B, 2 B). A pair of ventrolateral ciliated nuchal organs, between prostomium and peristomium (Fig. 2 B, indicated by arrows). Peristomium well defined, shorter than subsequent segments, with two pairs of tentacular cirri; dorsal pair similar in size to lateral antennae, slightly larger than dorsal cirri; ventral pair smaller than dorsal cirri, only visible ventrally (Figs. 1 B, 2 B). Intersegmentary rows of sub-cuticular glands covered by small sediment particles, visible under SEM (Fig. 2 A, indicated by arrows), giving an amber colour on some anterior chaetigers. Dorsal cirri with oval cirrophore and distinct cirrostyle, spherical to ovate. Ventral cirri small, conical, similar in size or slightly smaller than parapodial lobes, with numerous pores, visible under SEM (Fig. 2 C, indicated by arrow). Parapodial lobes conical, acute, with abundant glandular material. With 9 – 11 compound chaetae per parapodium, having longer blades and spines on anterior parapodia. All falcigers with unidentate blades, slightly hooked, strong dorso-ventral gradation in blade length: 3 – 4 upper falcigers having long blades (6 and 10.4 μm long blade on posterior and anterior parapodia respectively), with very long and curved spines on edge (Figs. 1 B, 2 D), 6 – 7 median with shorter blades and shorter spines (Fig. 2 E); and ventral-most with smooth blades (4.7 and 5.14 μm long on posterior and anterior parapodia respectively) (Figs. 1 D, 2 F). Slight anteroposterior gradation in length blades, shaft and blade seem to be partially fused in some falcigers (Fig. 2 E, indicated by arrow). One simple ventral chaeta in most posterior chaetigers, slender, smooth, pointed and slightly hooked. One acicula per parapodium, yellowish, stout, slightly blunt distally protruding out from parapodial lobe (Fig. 1 E). Pharynx slender, extending though five (in some paratypes six) segments, with a small and conical tooth near anterior margin (Fig. 1 A). Trepan not seen. Proventricle shorter than pharynx, cylindrical to barrel-shaped, extending through 3 segments (in some paratypes two), with 13 rows of muscle cells (Fig. 1 A) (variation in the type material is from 9 to 13). Pygidium bilobed, with two anal cirri similar to dorsal cirri.	en	Salcedo, Diana L., Martín, Guillermo San, Solís-Weiss, Vivianne (2011): Two new species of Syllidae (Annelida: Polychaeta) from the Southern Mexican Pacific. Zootaxa 2800: 41-52, DOI: 10.5281/zenodo.201624
BE47E558FFDAFFE65ED5CC8DFBC7F3F4.taxon	discussion	Remarks. This new species is the fourth known of the genus, in addition to Plakosyllis brevipes Hartmann- Schröder, 1956 from Atlantic European coasts, Mediterranean Sea and Australia, P. a m e r i c a n a Hartman, 1961 from southern California and P. quadrioculata Perkins, 1981 from Florida and the Caribbean Sea. This is thus the first record of the genus from the Mexican Pacific coasts. Plakosyllis curvispina n. sp. is characterized by having compound chaetae with long blades and long and distally curved spines (sometimes with shaft and blade partially fused), and by having all antennae in ventral position, partially or totally covered by the prostomium. The other three species of the genus have falcigers with short blades and short spines on margin, and only the lateral antennae are inserted in ventral position. Furthermore, P. americana has falcigers of a single kind with entirely smooth shafts. P. curvispina n. sp., has four eyes in trapezoidal arrangement, a dorsal pair and a ventral pair, and one pair of ventral eyespots, while P. americana has four dorsal eyes in a nearly transverse row and lacks eyespots. P. c u rvispina n. sp., has distally obliquely and blunt aciculae and ventral cirri similar in size or shorter than parapodial lobes, whereas both P. brevipes and P. quadrioculata have straight aciculae ending in acute tips and ventral cirri even longer than parapodial lobes. Habitat. Subtidal, in coarse sand, 10.5 to 12 m depth.	en	Salcedo, Diana L., Martín, Guillermo San, Solís-Weiss, Vivianne (2011): Two new species of Syllidae (Annelida: Polychaeta) from the Southern Mexican Pacific. Zootaxa 2800: 41-52, DOI: 10.5281/zenodo.201624
BE47E558FFDAFFE65ED5CC8DFBC7F3F4.taxon	distribution	Distribution. Western coast of Acapulco Bay, Southern Mexican Pacific. Etymology. The specific name refers to the curved spines of the compound chaetae.	en	Salcedo, Diana L., Martín, Guillermo San, Solís-Weiss, Vivianne (2011): Two new species of Syllidae (Annelida: Polychaeta) from the Southern Mexican Pacific. Zootaxa 2800: 41-52, DOI: 10.5281/zenodo.201624
BE47E558FFDDFFE95ED5CCE1FB0BF3F4.taxon	materials_examined	Material examined. Holotype: complete specimen (CPICML POH – 37 – 003), El Jardín E 3 B 1, 16 ° 49.436 ’ N and 99 ° 54.981 ’ W, 26 May 2006, 12 m, coarse sand. Paratypes: 9 specimens (CPICML POP- 37 - 004) El Jardín E 3 B 1, 16 ° 49.436 ’ N and 99 ° 54.981 ’ W, 26 May 2006, 12 m, coarse sand. 6 specimens (MNCN 16.01 / 13263), Palmitas E 2 B 2 16 ° 49.420 ’ N, 99 ° 54.733 ’ W, 25 May 2006, 10.5 m, coarse sand. 6 specimens (LACM-AHF POLY 2640), El Jardín E 3 B 2, 16 ° 49.436 ’ N and 99 ° 54.981 ’ W, 26 May 2006, 12 m, coarse sand. 6 specimens (AM: W. 37087), Palmitas E 2 B 1, 16 ° 49.420 ’ N and 99 ° 54.733 ’ W, 25 May 2006, 10.5 m, coarse sand. Additional material. 2 specimens (CPICML PO – 37 – 080), Palmitas E 2 B 1, 16 ° 49.420 ’ N and 99 ° 54.733 ’ W, 25 May 2006, 10.5 m, coarse sand. 7 specimens (CPICML PO – 37 – 080), Palmitas E 2 B 2 16 ° 49.420 ’ N, 99 ° 54.733 ’ W, 25 May 2006, 10.5 m, coarse sand. 4 specimens (CPICML PO – 37 – 080), El Jardín E 3 B 2, 16 ° 49.436 ’ N, 99 ° 54.981 ’ W, 26 May 2006, 12 m, coarse sand. 1 specimen (CPICML PO – 37 – 080), Caleta E 1 B 2, 16 ° 49.797 ’ N, 99 ° 54.062 ’ W, 25 May 2006, 12 m, coarse sand. Comparative material examined. Trypanosyllis coeliaca: 4 specimens (MNCN 16.01 / 6860). Spain: Mediterranean Sea, Columbrete Is., N of Columbrete Grande, 47 m. Trypanosyllis coeliaca: 3 specimens (MNCN 16.01 / 6863). Spain: Cantabric Sea, “ El Cachucho ”, Asturias.	en	Salcedo, Diana L., Martín, Guillermo San, Solís-Weiss, Vivianne (2011): Two new species of Syllidae (Annelida: Polychaeta) from the Southern Mexican Pacific. Zootaxa 2800: 41-52, DOI: 10.5281/zenodo.201624
BE47E558FFDDFFE95ED5CCE1FB0BF3F4.taxon	description	Description. Holotype complete specimen 6 mm long, 0.62 mm wide, with 66 chaetigers. Longest complete specimen 9.5 mm long, 0.72 mm wide, with 88 chaetigers. Body dorsoventrally flattened, colourless when preserved. Two dorsal transverse ciliated bands on each segment, visible under SEM: one with small tufts of cilia at midlength (Fig. 5 C, indicated by superior arrow), the other continuous, close to anterior margin (Fig. 5 C, indicated by inferior arrow). Additional small ciliated bands on parapodial lobes (Fig. 5 D, indicated by arrow) as well as on dorsal cirri and bases of lateral antennae (Fig. 5 A, indicated by inferior arrow). Prostomium oval to trapezoidal, wider than long, dorsally bilobed, with two pairs of eyes in trapezoidal arrangement, close to each other, anterior pair ventral and posterior pair dorsal; one pair of ventral eyespots (lacking in a few paratypes), close to anterior prostomial margin (Figs. 3 A, 3 B). Palps short, ovate, about half as long as prostomium, completely separated (Figs. 3 B, 5 B). Antennae short, inserted on anterior prostomial margin; median antenna slightly longer than combined length of prostomium and palps, with 12 articles (13 in some paratypes); lateral ones shorter, with 10 articles (Figs. 3 A, 5 A). Two nuchal organs as postero-lateral rows of cilia, one around each prostomial lobe (Fig. 5 A, indicated by superior arrow). Peristomium well defined, shorter than following segments, with two pairs of tentacular cirri; dorsal one similar to median antennae, with 14 – 15 articles; ventral one shorter, with 8 articles. Dorsal cirri short, thick, shorter than body width, slightly tapering distally, containing fibrillar material in each article, originating on short ceratophores (Figs. 3 A, 5 A); longer on anterior segments, alternating long (14 – 18 articles) and short (10 – 11 articles) in midbody and posterior chaetigers, alternating long (13 – 14 articles) and short (9 – 10 articles). Ventral cirri short, digitiform to conical, similar in size or slightly shorter than parapodial lobes. Parapodial lobes conical (Fig. 5 D). About 13 – 15 heterogomph compound chaetae per parapodium, with thick shafts and bidentate blades, having short and coarse spines on margin; both teeth similar in size on anterior falcigers, subdistal tooth smaller than distal one on median and posterior chaetae (Figs. 4 A, 4 C, 4 E). Marked dorso-ventral and antero-posterior gradation in blade length; anterior chaetae elongated, with slender blades (10.7 – 16.8 μm) (Figs. 4 A, 5 E), becoming shorter and thicker posteriorly (10 – 13.6 μm length) (Figs. 4 C, 4 E, 5 F). Dorsal and ventral simple chaetae only in most posterior chaetigers; dorsal one slender, smooth, bidentate, with subdistal tooth smaller (Figs. 4 G, 6 A); ventral simple chaeta similar to dorsal one, but with short spines on subdistal margin (Fig. 6 B). Two, sometimes three aciculae in anterior parapodia (one larger and thicker) (Figs. 4 B, 5 D), and a single acicula in midbody and posterior parapodia (Figs. 4 D, 4 F), all stout, straight, acute, protruding from parapodial lobes. Pharynx long, through nine segments (Fig. 3 A), (variation in type material is from 7 to 9), with a crown of ten soft papillae, surrounded by sinuous glands (Fig. 3 A, indicated by arrow) and dark ovate glands inserted between the folds of latter (Fig. 3 A, indicated by arrow). Pharyngeal tooth conical, small and thin, trepan with 10 small, short and transparent teeth, very difficult to distinguish in some specimens (Fig. 6 C, indicated by arrow). Proventricle short, extending through 4 segments (variation among paratypes from 3 to 6), with 19 muscle cell rows (Fig. 3 A) (variation among paratypes from 17 to 21). Pygidium with two anal cirri, similar in length to dorsal ones at midbody, with 7 articles (or 8 in some paratypes).	en	Salcedo, Diana L., Martín, Guillermo San, Solís-Weiss, Vivianne (2011): Two new species of Syllidae (Annelida: Polychaeta) from the Southern Mexican Pacific. Zootaxa 2800: 41-52, DOI: 10.5281/zenodo.201624
BE47E558FFDDFFE95ED5CCE1FB0BF3F4.taxon	discussion	Remarks. This species is characterized by having the anterior pair of eyes in ventral position and the posterior one dorsally, as well as by having bidentate compound chaetae and a small trepan with transparent teeth. The genus Trypanosyllis currently has more than 20 valid species (Çinar 2007; Nogueira & Fukuda 2008). Of these, only T. parvidentata Perkins, 1981 and T. coeliaca Claparède, 1868 resemble T. microdenticulata n. sp. All three have small trepans, sinuous glands surrounding the pharynx, and antennae, dorsal cirri, pharynx and proventricle similar in size. However, unlike T. microdenticulata n. sp., the other two species have two pairs of eyes in dorsal position. Additionally, T. parvidentata has a solitary acicula throughout the body. Unlike T. microdenticulata n. sp., the anterior falcigers of T. coeliaca have slender and longer blades and longer spines on distal margin, while T. parvidentata has longer falcigers with both teeth similar in size (in T. microdenticulata n. sp., the subdistal tooth is smaller in most falcigers). Trypanosyllis zebra (Grube, 1860) is one of the most common littoral syllids, even in the Mexican Pacific, and is indeed similar to T. microdenticulata n. sp., but the former has a distinctive colour pattern, as well as much longer antennae and dorsal cirri. Furthermore, the pharynx in T. zebra is proportionally shorter and the proventricle is longer, and the species lacks the dorsal transverse ciliated bands. Most specimens were dissected and their pharynx examined. All had a small and thin pharyngeal tooth, very difficult to distinguish, and a trepan with about 10 very small and transparent teeth. Even after dissection of the pharynx, the trepan is very difficult to observe in most of the specimens, since sometimes the teeth are shorter than the length of the papillae and also because of its colour and texture, it can be easily confused with pharyngeal tissues. This could be due to the fact that the teeth of the trepan are made up of soft and fibrous tissues when they begin to develop in young organisms (Fig. 6 C, indicated by arrow), becoming larger and rigid structures in adults (Fig. 6 D). Therefore, such a structure can be overlooked and assumed to be absent in some specimens depending on their stage of development and it could also be lost accidentally (San Martín 2003). However, after careful examination of a large number of specimens, it was concluded that all have a trepan, even small individuals although they may be minute and difficult to see. In some species such as T. zebra, the presence of a pharyngeal tooth seems to be size-dependent, as mid-sized and large specimens lack one (San Martín 1984, 2003; San Martín et al 2008). Nonetheless, in T. microdenticulata n. sp. the pharyngeal tooth is always present, while the only size-related differences is trepan teeth. The trepan is a diagnostic character of the genus (San Martín 2003), and it is considered homoplasic, so that it should be used with care to differentiate lower taxa (Aguado & San Martín 2009). 6. SEM of Trypanosyllis microdenticulata n. sp. (A) Dorsal simple chaeta. (B) Ventral simple chaeta. (C) Everted pharynx, small specimen (Arrow: soft teeth). (D) Hard teeth, larger specimen. Scale: (A) 2 µm. (B) 1 µm. (C) 10 µm. (D) 20 µm. Habitat. Subtidal coarse sand, 10.5 to 12 m depth.	en	Salcedo, Diana L., Martín, Guillermo San, Solís-Weiss, Vivianne (2011): Two new species of Syllidae (Annelida: Polychaeta) from the Southern Mexican Pacific. Zootaxa 2800: 41-52, DOI: 10.5281/zenodo.201624
BE47E558FFDDFFE95ED5CCE1FB0BF3F4.taxon	distribution	Distribution. Western coast of Acapulco Bay, Southern Mexican Pacific. Etymology. The specific name refers to the small size of the teeth belonging to the trepan.	en	Salcedo, Diana L., Martín, Guillermo San, Solís-Weiss, Vivianne (2011): Two new species of Syllidae (Annelida: Polychaeta) from the Southern Mexican Pacific. Zootaxa 2800: 41-52, DOI: 10.5281/zenodo.201624
