CHAPTER 30 



Joan M. Uebelacker 

 FAMILY SYLLIDAE Grube, 1850 



INTRODUCTION 



Syllids are small, slender-bodied polychaetous annelids, often less 

 than 10 mm in length, although members of the subfamily Syllinae may 

 reach several centimeters. The prostomium is rounded and usually has 

 two pairs of eyes, three antennae, and a pair of anteroventral palps. 

 The palps may be free from each other or partially to completely fused 

 along their length. The peristomium has either one or two pairs of 

 tentacular cirri. Nuchal organs are present and are variably defined. 

 Dorsal cirri are conspicuous, of varying lengths, and smooth to arti- 

 cled. Ventral cirri are present or absent. Parapodia are supported by 

 acicula and are uniramous in non-reproductive individuals. In sexually 

 mature individuals, most parapodia are subbiramous, due to the develop- 

 ment of natatory setae arising from the body wall below the dorsal 

 cirri. Setae are simple or composite. The eversible pharynx usually 

 has a single median tooth, and/or a distal circlet of teeth; in a few 

 taxa it is unarmed. The pharynx leads posteriorly into a large, muscu- 

 lar proventricle. 



The family contains 56 recognized genera and more than 600 species 

 (Fauchald, 1977a). Seventy-three species representing 25 genera have 

 been identified from the Gulf of Mexico BLM-0CS studies. Of these, 28 

 are probably new to science and an additional 13 previously described 

 species are newly reported from this region. 



PRINCIPAL DIAGNOSTIC CHARACTERS 



The Syllidae are divided into the subfamilies Autolytinae, Exogoni- 

 nae, Eusyllinae, and Syllinae as follows: 



Autolytinae: Palps partially to completely fused. Nuchal organs 

 forming epaulettes. Tentacular cirri numbering two pairs. Dorsal cirri 

 smooth or with single long article on basal cirrophore. Ventral cirri 

 absent. Pharynx long, coiled or sinuous, having a distal circlet of 

 teeth (trepan). 



Exogoninae: Body small. Palps fused dorsally over half to entire 

 length. Nuchal organs generally indistinct. Tentacular cirri numbering 

 one or two pairs. Dorsal cirri short, and ovoid, clavate, fusiform, or 

 digitiform in shape. Ventral cirri present. Pharynx straight, armed 

 with a single large tooth. 



Eusyllinae: Palps fused basally. Nuchal organs often large, dis- 

 tinct. Tentacular cirri numbering one or two pairs. Dorsal cirri 

 variable in length, usually smooth. Ventral cirri present. Pharynx 

 usu?My straight, with teeth or unarmed. 



Syllinae: Palps separate. Nuchal organs usually small and indis- 

 tinct. Tentacular cirri numbering *~wo pairs. Dorsal cirri usually 

 elongate, articled. Ventral cirri present. Pharynx straight, having a 

 large dorsal tooth and/or trepan. 



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