(Annelida: Syllidae) from Saudi Arabian Red Sea, with the Description 3 of a New Endosymbiotic Species and a Dichotomous Key for the Indo-Pacific Species

1 Running head: Haplosyllis from the Red Sea.

2 Haplosyllis (Annelida: Syllidae) from Saudi Arabian Red Sea, with the description 3 of a new endosymbiotic species and a dichotomous key for the Indo-Pacific species

4 Diego Cepeda1, Daniel Martin2, Temir A. Britayev3, Ali M. Al-Aidaroos4 and Patricia 5 Lattig1

6 1. Dept. Biodiversity and Evolutionary Biology, National Museum of Natural 7 Sciences of Madrid (MNCN). C/ José Gutiérrez Abascal 2, 28006 Madrid, 8 Spain. Phone: +34685345222 9 2. Dept. Marine Ecology, Centre for Advanced Studies of Blanes (CEAB). Carrer 10 d’accés a la Cala Sant Francesc 14, 17300 Blanes (Girona), Spain. 11 3. A.N. Severtsov Institute of Ecology and Evolution (RAS), Russian Academy of 12 Sciences. Leninsky pr. 33, 117071 Moscow, Russia. 13 4. Dept. Of Marine Biology, Faculty of Marine Sciences, King Abdulaziz 14 University, PO Box 80207, Jeddah 21589, Saudi Arabia.

15 Abstract: The knowledge on the Haplosyllis species in the Saudi Arabian Red Sea is 16 rather limited, being the so-called cosmopolitan Haplosyllis spongicola and Haplosyllis 17 djiboutiensis apparently present all along the region as the only reported species. 18 However, both revealed to be species-complex, the former mostly composed by 19 European species and the later being distributed in the Indo-Pacific area. Recently, 20 several new species have been described following more comprehensive taxonomic 21 studies in the respective areas. Haplosyllis leylae sp. nov. can be framed within the 22 “djiboutiensis” complex. The new species, which is herein fully described and 23 illustrated, can be clearly distinguished by the combined presence of numerous, small, 24 dorsal granules, the low number of articles on each dorsal cirrus and the chaetal 25 morphology. A dichotomous key of the Indo-Pacific species of Haplosyllis and new 26 information on Haplosyllis eldagainoae are also included.

27 Key words: Polychaeta, Haplosyllis, Red Sea, new species, taxonomy, dichotomous 28 key.

29 Acknowledgements: The author Patricia Lattig helds a post-doctoral contract under the 30 JAE-DOC program of the Consejo Superior de Investigaciones Científicas in the Museo 31 Nacional de Ciencias Naturales of Madrid (MNCN-CSIC). This paper has been partially 32 supported by the projects CTM2014-57949-R funded by the Spanish Ministry of 33 Economy and Competitiveness, and the projects CTM2010-22218 and CTM2013- 34 43287-P funded by the Spanish State Research Plan, and the Consolidated Research 35 Group of Marine Benthic Ecology of the Generalitat de Catalunya (2014SGR120). The 36 scientific research cooperation between King Abdulaziz University (KAU), Faculty of 37 Marine Sciences (FMS), Jeddah, Saudi Arabia, and the Senckenberg Research Institute 38 (SRI), Frankfurt, Germany, in the framework of the Red Sea Biodiversity Project, 39 during which the present material was collected, was funded by KAU GRANT NO.

40 I/1/432-DSR. The authors acknowledge, with thanks, KAU and SRI for technical and 41 financial support.

42 This article is registered in ZooBank under urn:lsid:zoobank.org:pub:8CC7BAA7- 43 5BE5-47F7-AA41-D89DF698E155

68 Introduction

69 The Red Sea, a relatively small, semi-enclosed basin located at the NW edge of the 70 Indian Ocean, is a highly biodiverse area. Together with some other regions of this 71 ocean, it encompasses one of the highest levels of marine endemism (Head 1987; 72 Sheppard et al. 1992) due to different oceanographic reasons. Among them, the cold 73 nutrient-rich water current that separates the Gulf of Aden from the rest of the Arabian 74 Sea, together with other physical and environmental barriers defined by the currents and 75 the geography of the region (DiBattista et al. 2016).

76 807 valid polychaete taxa have been reported for the Arabian region of the Red Sea, 77 with almost 20% being considered endemic. Among them, 105 are syllids, which show 78 a 26% of endemisms (Wehe and Fiege 2002).

79 Within syllids, the previous knowledge on the species of Haplosyllis is scarce and 80 confusing. Haplosyllis djiboutiensis Gravier, 1900, the first species described, was 81 reported widely all along the region (Amoureux 1983; Amoureux et al. 1980; Ben- 82 Eliahu 1972, 1977; Ben-Eliahu and Safriel 1982; Fauvel 1919, 1927, 1955; Hartman 83 1974; Hartmann-Schröder 1960; Kiseleva 1971; Mohammad 1976, 1980; Monro 1937). 84 The species seems to be easily recognized by characteristically having two chaetae per 85 parapodia with very different morphologies. These characters also allows to distinguish 86 it from the type species, Haplosyllis spongicola (Grube, 1855), which seems to be 87 absent from the region (Lattig and Martin, 2009).

88 Further research along the Indo-Pacific, however, revealed the existence of numerous 89 populations belonging to the “djiboutiensis” species-complex (e.g. Qatar and Abu 90 Dhabi, Lattig and Martin, 2011; Australia, Lattig et al. 2010a; Indonesia, Lattig et al. 91 2010b; Philippines, Lattig, personal observations). They show very small differences 92 (e.g. in chaetal denticles, apical teeth size, length of the mid-joining point, dorsal 93 granulation) and are, thus, extremely difficult to distinguish based on morphological 94 techniques. Some of those populations are difficult to distinguish from the H. 95 djiboutiensis complex, but a group of small morphological differences allow their 96 identity as different taxa, such as Haplosyllis nicoleae Lattig, Martin and Aguado, 2010 97 from Indonesia. In contrast, there are some other species of the genus that can be clearly 98 distinguished, some of them being sponge endobionts.

99 The present paper contributes to the growing knowledge on the biodiversity of the Saudi 100 Arabian Red Se by describing a new sponge endobiont species of Haplosyllis, H. leylae 101 sp. nov. In addition, it provides a new record of H. eldagainoae and a dichotomous key 102 of the species of the genus currently known for the Indo-Pacific.

103 Materials and methods

104 The specimens of Haplosyllis were collected during the third survey of the Red Sea 105 Biodiversity Project in July 2013 organized by the Faculty of Marine Sciences of King 106 Abdulaziz University (Jeddah, Saudi Arabia) in cooperation with the Senckenberg

107 Natural Research Society (Frankfurt am Main, Germany). The host sponges, Hyrtios 108 erectus (Keller, 1889) and Aaptos cf. aaptos (Schmidt, 1864), were collected from 109 rocky shores and reef flats facing Al Wajh and Duba (Saudi Arabia).The sponges and 110 polychaetes were fixed and preserved in 100% ethanol, then polychaetes were carefully 111 removed from sponges. The specimens were deposited at the Senckenberg Museum of 112 Natural History of Frankfurt (SRI, Germany), the King Abdulaziz University Marine 113 Museum of Jeddah (KAUMM, Saudi Arabia) and the National Museum of Natural 114 Sciences (MNCN, Spain).

115 A Leica MZ16A stereomicroscope and a Zeiss 66649 optic microscope were used for 116 the study of the specimens. Scanning electron microscope (SEM) images were captured 117 with a FEI INSPECT microscope at the Electron and Confocal Microscopy Laboratory, 118 and stereomicroscope images with a Leica DFC550 camera attached to the Leica 119 MZ16A stereomicroscope in the MNCN. Specimens for SEM observations were run 120 through a graded series of ethanol-hexamethyldisilazane (HMDS) ending in pure 121 HMDS before being air dried and coated with gold. Illustrations were made using a 122 camera lucida attached to a Zeiss SV8 binocular and digitized using Adobe Photoshop 123 6.0 and Adobe Illustrator CC 2014 (Adobe Systems ©).

124 The definition and explanation of terms used to describe the morphology of Haplosyllis 125 can be found in Martin et al. (2003) and Lattig and Martin (2009). The terms used to 126 describe the chaetal morphology are: length of main fang (LMF), chaetal width (SW), 127 upper side (US) of main fang (MF) and mid-joining point (MJP) between teeth and MF.

128 Results & Discussion

129 Family Syllidae Grube, 1850

130 Subfamily Syllinae Grube, 1850

131 Genus Haplosyllis Langerhans, 1879

132 Haplosyllis: San Martín, 2003; Lattig et al., 2007; Lattig & Martin, 2009

133 Haplosyllis eldagainoae Lattig and Martin, 2011

134 Haplosyllis eldagainoae Lattig and Martin 2011: 116-117, Figs. 3-6.

135 Haplosyllis spongicola: Magnino & Gaino 1998: Fig. 5A-C; Magnino et al. 1999: Fig. 3B-C.

136 EXAMINED MATERIAL

137 Duba (Saudi Arabian Red Sea), 27°20'39.70'' N 35°41'41.50'' E, shallow waters to 138 infralittoral zone, endosymbiont of the sponge Aaptos cf. aaptos. SRI XXXXX (25), 139 some of them fragmented; KAUMM (25), some of them fragmented; MNCN XXXX 140 (7) some of them fragmented; MNCN XXXX (4), two of them lacking the last posterior 141 segments and pygidium, prepared for SEM.

142 TAXONOMIC REMARKS

143 The studied specimens agree quite well with those described by Lattig and Martin 144 (2011) from the Egypt Red Sea and the western coast of Africa. However, some of the 145 examined specimens are slightly bigger, up to 4-6 mm long and 0.4-0.6 mm wide 146 excluding parapodia (2-4 mm and 0.3 mm in the type material). Furthermore, the small 147 dorsal granules on posterior segments and parapodial lobes were less conspicuous. 148 Despite their large size, the number of segments, 16-30, is not correspondingly higher.

149 ECOLOGY

150 Haplosyllis eldagainoae was previously reported as strict endosymbiont of the sponge 151 Theonella swinhoei Gray, 1868, likely maintaining a mutualistic relationship. This is 152 thus the second report of the species and the first as endosymbiont of another host 153 sponge, Aaptos cf. aaptos.

154 DISTRIBUTION

155 Red Sea; western Indian Ocean (Tanzania). This is the first record of the species for the 156 Saudi Arabian Red Sea.

157 Haplosyllis leylae sp. nov. Cepeda and Lattig

158 (Figures 1-3)

159 TYPE MATERIAL

160 Al Wajh, Saudi Arabian Red Sea, 26º14’47.80’’N 36º26’47.80’’E, shallow waters, 161 rocky shore with sandy bottom and reef flat with rocky and sandy bottoms, 162 endosymbiont of the sponge Hyrtios erectus. Holotype. SRI XXXXX: adult lacking the 163 last posterior segments and pygidium. Paratypes. SRI XXXXX (5), KAUMM XXXX 164 (2), KAUMM XXXX (4) prepared for SEM.

165 NON-TYPE MATERIAL

166 Alkhuraybah, Saudi Arabian Red Sea, 27º47’24.66’’N 35º07’53.40’’E, shallow waters, 167 backward slope with strong sediment impact, endosymbiont of the sponge Hyrtios sp. 168 MNCN XXXX (1).

169 DIAGNOSIS

170 Small dark-brown granulation in palps, prostomium and anterior segments. Mid-body 171 and posterior dorsal cirri short, with a single article. One chaeta per parapodium, rarely 172 two. Mid-body and posterior chaetae with MJP straight and long. Aciculae straight and 173 with curved tip. Reproduction by means of stolons.

174 DESCRIPTION

175 Body small, brittle, fragile, sub-cylindrical, gradually tapering from mid-body to 176 posterior end (Figures 1A-C; 2A-E, H; 3A), at least 3-5 mm (holotype 4 mm), with a 177 minimum 9-19 segments (holotype 15); about 0.5 mm wide (excluding parapodia). 178 Body pale-cream, darker around proventricle, with small dark-brown granulation in

179 palps, prostomium and anterior segments (Figure 2A-D). Prostomium sub-pentagonal, 180 with two pairs of spherical, red to brown small eyes in trapezoidal arrangement, anterior 181 ones bigger than posterior (Figures 1A, C and 2A-C). Median antenna progressively 182 tapering towards end, inserted on medium of prostomium, long and whip-shaped, with 183 10-14 sub-quadrangular articles (6-9 in small individuals), last one longest, sub- 184 triangular; lateral antennae inserted on anterior margin of prostomium, similarly wide 185 from base to tip, shorter than median antenna, with 6-9 sub-quadrangular articles, last 186 one non-distinguishable from remaining ones (Figures 1A-C and 2A-D). Palps slightly 187 longer than prostomium, broadly sub-rectangular, fused at their bases but clearly 188 divergent all along their length (Figures 1A-C; 2A-D; 3A-B). Sensory organs of palps 189 and nuchal organs not seen. Pharynx pale-cream, extending through 5-6 segments 190 (occasionally 4 in smallest individuals), usually everted, with a short anterior tooth 191 surrounded by a crown of 10 soft papillae (Figure 3A-B). Proventricle short, cylindrical, 192 extending through 3-5 segments, with 27-38 muscular cell-rows (Figures 1A and 2A). 193 Peristomium well defined, shorter than segment 1 (Figures 1C and 2A-C). Dorsal 194 tentacular cirri longer than ventral ones, with 10-15 articles (7-9 in small individuals), 195 similar in shape to median antenna (Figures 1A-C and 2A-C). Ventral tentacular cirri 196 with 5-8 articles (3-4 in small individuals, 12 in one specimen), similar in shape to 197 lateral antennae (Figures 1A-C and 2A-C). Dorsal cirri similar to lateral antennae and 198 ventral tentacular cirri (Figures 1A-E; 2A-D; 3C), with a distinct length pattern: first 199 cirri longer than remaining ones (10-17 articles), second short (3-5), third to fourth long 200 (6-10), fifth shorter (3), then progressively decreasing in length and number of articles 201 up to only one at chaetiger 8, elongated and sub-cylindrical to digitiform, decreasing in 202 width from base to tip (Figures 1D-E and 3D, F). Ventral cirri digitiform, with one 203 article, broad and sub-triangular, as long as or slightly shorter than parapodial lobes 204 (Figures 1D-E and 3D-F). Chaetae all bidentate, similar in shape, different in size, 205 anterior ones small, one per parapodium, occasionally two (Figures 1F-H; 2F; 3G-I). 206 Chaetae of mid-body and posterior chaetigers with US of MF lacking spines, with low 207 wrinkled ridges only visible under SEM (Figure 3H). MJP straight and long (at least in 208 mid-body and posterior chaetae) (Figures 1F-H; 2F; 3G-I). LMF progressively longer 209 from anterior to mid-body and posterior chaetae, as long as SW (Figures 1F-H and 3G- 210 I). Apical teeth equal in length, clearly separated, distal tooth shorter than proximal one 211 (Figures 1F-H; 2F; 3G-I). Aciculae broad, 1/3 wider than chaetal shaft, golden, some 212 protruding out of parapodial lobe (especially at mid-body and posterior segments), of 213 two kinds: (1) with straight tip (Figures 1I and 2G) and (2) with long, pointed, curved 214 tip upwards directed (Figures 1I and 2G-H), 1-2 per parapodia (when 1, only curved). 215 Pygidium distally wide and rounded (Figure 2E), with two short anal cirri with a single 216 digitiform article.

217 REPRODUCTION

218 Haplosyllis leylae sp. nov. reproduces by means of stolons, having 9-10 chaetigerous 219 segments with a pair of blackish parapodial ocular spots per segment (Figures 1J and 220 2I). Stolons may have up to three chaetae per parapodium, with different sizes, with MF 221 directed downwardly, and a single acicula with long, pointed, curved tip 90º bent.

222 Capillary chaetae not observed. No free-swimming stolons were found, thus the final 223 shape of the anterior region cannot be assessed.

224 ECOLOGY

225 The species lives as endosymbiont of the sponges Hyrtios erectus and Hyrtios sp. in 226 shallow infralittoral bottoms (up to 30 m depth), in rocky shores, reef flats and 227 backward slopes with strong sediment impact, both in hard and soft bottoms.

228 DISTRIBUTION

229 Indian Ocean, Saudi Arabian Red Sea (Al Wajh and Alkhuraybah).

230 ETYMOLOGY

231 The species is dedicated to Leyla Ordóñez, a good friend of the last author who is 232 always interested in our polychaete research.

233 REMARKS

234 Haplosyllis leylae sp. nov. can be clearly distinguished from the type species, 235 Haplosyllis spongicola, in having a smaller and narrower body dorso-ventrally flattened 236 with pigmentation in palps, prostomium and anterior segments (absent in H. 237 spongicola). The new species also lacks spines in the US of the MF (present in H. 238 spongicola) and has short dorsal cirri with a single article from chaetiger 8 (long, whip- 239 shaped, with numerous articles in H. spongicola).

240 Some other species of Haplosyllis present in the Indo-Pacific are Haplosyllis aciculata 241 Lattig, Martin & Aguado, 2010, H. djiboutiensis, H. eldagainonae, H. 242 giuseppemagninoi Lattig & Martin, 2011, H. ingensicola Lattig, Martin & Aguado, 243 2010, H. nicoleae, H. sanchoi Lattig, Martin & San Martín, 2010 and H. uncinigera 244 (Grube, 1878). Haplosyllis djiboutiensis, H. nicoleae and H. uncinigera have two kinds 245 of chaetae in mid-body and posterior parapodia, and chaetae from the same parapodium 246 have different MJP shape (only one kind with long and straight MJP in H. leylae sp. 247 nov.). Additionally, H. uncinigera has 3-4 aciculae per posterior parapodium (1-2 in H. 248 leylae sp. nov.) and the pharynx extends through about 11 segments (4-6 in H. leylae sp. 249 nov.).

250 Haplosyllis aciculata and H. ingensicola can be easily distinguished by having long 251 dorsal cirri through all body length, similar to or longer than body width (anterior longer 252 than medium and posterior but always shorter than body width in H. leylae sp. nov.). 253 The new species resembles H. ingensicola in having dark-brown pigmentation on palps, 254 prostomium and anterior segments, but can be easily distinguished by the 255 aforementioned cirri length.

256 Haplosyllis eldagainonae is similar to Haplosyllis leylae sp. nov. in having small and 257 fragile bodies and short dorsal and anal cirri with 1-2 articles, but can be distinguished

258 by having the last article of dorsal cirri very long and pointed and chaetae with short, 259 curved MJP (shorter last articles and long, straight MJP in H. leylae sp. nov.).

260 Haplosyllis leylae sp. nov. resembles H. sanchoi in having anterior dorsal cirri longer 261 than those from mid-body and posterior segments, all of them shorter than body width, 262 but can be easily distinguished by having posterior chaeta with short MJP and US of 263 MF notoriously longer than SW (long MJP and US of MF as long as SW in H. leylae 264 sp. nov.).

265 Haplosyllis giuseppemagninoi is the species most closely resembling H. leylae sp. nov., 266 both having anterior dorsal cirri longer than those from mid and posterior body but all 267 shorter than body width, chaetae with long, straight MJP and US of MF as long as SW. 268 However, they can be distinguished by the presence of dark-brown pigmentation on 269 palps, prostomium and anterior segments (absent in H. giuseppemagninoi), the straight 270 acicula (absent in H. giuseppemagninoi) and the single (rarely two) acicula on posterior 271 parapodia (2-4 in H. giuseppemagninoi).

272 Key for the Indo-Pacific species of Haplosyllis

273 1. Mid-body and posterior parapodia with chaetae of different shape, dorsal ones with 274 straight, long MJP and ventral ones with curved, short MJP……………………………2 275 — Mid-body and posterior parapodia with all chaetae similarly in shape, or only one 276 chaeta per parapodium…………………………………………………………………4 277 278 2. Pharynx extending through about 11 segments. 3-4 aciculae per posterior 279 parapodium…………………………………………………………………H. uncinigera 280 — Pharynx extending through 4-6 segments. 1-2 aciculae per posterior 281 parapodium………………………………………………………………………………3 282 283 3. Body fragile, translucent. Mid-body ventral chaetae with apical teeth similar in 284 size……………………………………………………………………………H. nicoleae 285 — Body robust, opaque. Mid-body ventral chaetae with apical proximal tooth shorter 286 than distal one……………………………………………………………H. djiboutiensis 287 288 4. Mid-body parapodia with 3-5, 5-8 or up to 14 chaetae. MJP long and straight……5 289 — Mid-body parapodia with 1-3 chaetae. MJP intermediate or short, curved, diagonal 290 or straight………………………………………………………………………………7 291 292 5. Up to 14 chaetae per mid-body parapodium……………………………H. cratericola 293 — Up to 8 chaetae per mid-body parapodium…………………………………………6 294 295 6. Aciculae with curved tip absent; three or more aciculae per 296 parapodium………………………………………………………………………H. ohma 297 — Aciculae with curved tip present; two or three aciculae per 298 parapodium…………………………………………………………………H. imajimai 299 300 7. Anterior chaetae with marks of fusion between blade and shaft opposite to MF. 301 Proximal tooth smaller than distal one………………………………H. anthogorgicola

302 — Anterior chaetae without marks of fusion between blade and shaft opposite to MF. 303 Proximal tooth slightly longer than distal one…………………………………………8 304 305 8. Dorsal cirri long through all body length, similar to body width or longer…………9 306 — Anterior dorsal cirri longer than mid-body and posterior dorsal cirri, which are short 307 and not longer than body width………………………………………………………12 308 309 9. Dorsal cirri broad, similar in length all along the body. MJP short and 310 curved……………………………………………………………………H. crassicirrata 311 — Dorsal cirri slender, alternating between long and short. MJP long or intermediate, 312 straight or diagonal……………………………………………………………………10 313 314 10. Mid-body chaetae with MJP diagonal. Long spines on MF present. Posterior 315 aciculae broad and straight……………………………………………………H. tenhovei 316 — Mid-body chaetae with MJP straight. Spines on MF short or absent. Posterior 317 aciculae broad and with curved tip……………………………………………………11 318 319 11. Dark-brown pigment on palps, prostomium and anterior segments. Spines on MF of 320 mid-body chaetae (only visible under SEM). Anterior straight aciculae 321 present……………………………………………………………………H. ingensicola 322 — Pigmentation absent. Spines on MF of mid-body chaetae absent. Anterior straight 323 aciculae absent………………………………………………………………H. aciculata 324 325 12. Anterior chaetae with MJP long or short, straight or diagonal……………………13 326 — Anterior chaetae with MJP short and curved………………………………………16 327 328 13. Posterior chaetae with MJP short. US of MF notoriously longer than 329 SW……………………………………………………………………………H. sanchoi 330 — Posterior chaetae with MJP long or intermediate. US of MF similarly or shorter than 331 SW……………………………………………………………………………………14 332 333 14. Anterior chaetae with MJP short and diagonal. A deep hold on US of MF 334 present…………………………………………………………………………H. sandii 335 — Anterior chaetae with MJP long and straight. A deep hold on US of MF absent…15 336 337 15. Small dark-brown granulation in palps, prostomium and anterior segments. Acicula 338 straight. One chaeta per posterior parapodium, rarely two……………H. leylae sp. nov. 339 — Granulation as above absent. Straight acicula absent. 2-4 chaetae per posterior 340 parapodium…………………………………………………………H. giuseppemagninoi 341 342 16. Last article of dorsal cirri long. Posterior dorsal cirri very short (1 343 article)…………………………………………… ………………………H. eldagainoae 344 — Last article of dorsal cirri short. Posterior dorsal cirri short (2-6 articles) 345 ………………………………………………………………………………H. basticola 346 347 REFERENCES 348 349 Amoureux L (1983) Annélides Polychètes du golfe d’Aqaba (Mer Rouge). Description 350 d’un génère nouveau et de deux espèces nouvelles. Bull Mus Natl Hist Nat, B, 351 Adansonia 3:723-742.

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401 Lattig P, Martin D, Aguado MT (2010a) Four new species of Haplosyllis (Polychaeta: 402 Syllidae: Syllinae) from Indonesia. J Mar Biol Assoc UK 90(4):789-798. 403 404 Lattig P, Martin D, San Martín G (2010b) Syllinae (Syllidae: Polychaeta) from 405 Australia. Part 4. The genus Haplosyllis Langerhans, 1879. Zootaxa 2252:1-36. 406 407 Lattig P, San Martín G, Martin D (2007) Taxonomic and morphometric analyses of the 408 Haplosyllis spongicola complex (Polychaeta: Syllidae: Syllinae) from Spanish Seas, 409 with re-description of the type species and descriptions of two new species. Sci Mar 410 71:551-570. 411 412 Magnino G, Gaino E (1998) Haplosyllis spongicola (Grübe) (Polychaeta, Syllidae) 413 associated with two species of sponges from east Africa (Tanzania, Indian Ocean). 414 PSZNI Mar Ecol 19:77-87. 415 416 Magnino G, Sarà A, Lancioni T, Gaino E (1999) Endobionts of the coral reef sponge 417 Theonella swinhoei (Porifera, Demospongiae). Invertebr Biol 118:213-220. 418 419 Martin D, Britayev TA, San Martín G, Gil J (2003) Interpopulation variability and 420 character description in the sponge-associated Haplosyllis spongicola complex 421 (Polychaeta: Syllidae). Hydrobiologia 496:145-162. 422 423 Mohammad MBM (1976) Relationships between the biofouling and growth of the pearl 424 oyster Pinctada fucata (Gould) in Kuwait, Arabian Gulf. Hydrobiologia 51:129-138. 425 426 Mohammad MBM (1980) Polychaete Annelids from Kuwaitian Islands, Arabian Gulf, 427 with descriptions of four new species. Zool J Linn Soc-Lond 69:31-42. 428 429 Monro CCA (1937) The John Murray Expedition 1933-34. Polychaeta. Sci Rep Zool 430 4:243-321. 431 432 San Martín G (2003) Annelida, Polychaeta II: Syllidae. CSIC Press, Madrid. 433 434 Sheppard C, Price A, Sheppard ALS (1992) Marine ecology of the Arabian Region. 435 Patterns and processes in extreme tropical environments. Academic Press, London, San 436 Diego, New York, Boston, Sydney, Tokyo, Toronto. 437 438 Wehe T, Fiege D (2002) Annotated checklist of the polychaete species of the seas 439 surrounding the Arabian Peninsula: Red Sea, Gulf of Aden, Arabian Sea, Gulf of Oman, 440 Arabian Gulf. Fauna of Arabia 19:7-238. 441 442 443 444 445 446 447 448 449 450

451 FIGURES 452

453 454 455 Fig. 1. Haplosyllis leylae sp. nov. drawing: (A) Anterior body, dorsal view; (B) 456 Anterior body, ventral view; (C) Anterior body, lateral view; (D) Anterior parapodium; 457 (E) Posterior parapodium; (F) Anterior chaeta; (G) Mid-body chaeta; (H) Posterior 458 chaeta; (I) Mid-body aciculae; (J) Stolon. Scale bars: A-C and J, 1 mm; D-E, 100 µm; 459 F-I, 10 µm. A-I: Holotype SRI 24317; J: Paratype KAUMM Polychaeta1. 460 461 462 463 464 465 466 467

468 469 470 Fig. 2. Haplosyllis leylae sp. nov. stereomicroscope and optical microscope pictures: 471 (A) Anterior body, dorso-lateral view; (B) Anterior body, dorsal view; (C) Anterior 472 body, lateral view; (D) Anterior body, ventral view; (E) Complete body, ventro-lateral 473 view; (F) Mid-body chaeta; (G-H) Mid-body aciculae; (I) Stolon. Scale bars: A and D, 474 500 µm; B and C, 200 µm; E, 1 mm; F-H, 10 µm; I, 100 µm. A-G: SRI 24317; E and I 475 correspond to specimens that were completely used for molecular purposes.

476 477 478 Fig. 3. Haplosyllis leylae sp. nov. SEM pictures: (A) Anterior body, ventral view; (B) 479 Anterior body, ventral view, showing pharynx with soft papillae; (C) Third parapodium, 480 dorsal view, showing the dorsal cirrus; (D) Seventh parapodium, ventral view, showing 481 the dorsal and the ventral cirri; (E) Mid-body parapodia, ventral view; (F) Detail of mid- 482 body parapodia; (G) Anterior chaeta; (H) Mid-body chaeta; (I) Posterior chaeta. Scale 483 bars: A, 300 µm; B and E, 50 µm; C, 25 µm; D, 15 µm; F, 20 µm; G-I, 5 µm. A-I: 484 KAUMM Polychaeta2.