Genus Microphthalmos Mecznikow, 1865 



TYPE SPECIES: Microphthalmias sczelkowii Mecznikow, 1865. 

 REFERENCES : 

 Fauvel, 1923:249. 

 Pettibone, 1963:102. 

 Hartmann-Schroder, 1971:137. 

 Fauchald, 1977a:76. 

 Westheide, 1977a:106-108. 



DIAGNOSIS: Prostoraium with 2-3 filiform antennae and simple, filiform 

 palps. Median antenna, when present, attached medially on prostomium. 

 Six pairs of tentacular cirri. Parapodia subbiramous, usually with few 

 notosetae. Pygidium with anal cirri and lamella. Pharynx with papil- 

 lose margin, jaws absent. Typically interstitial. 



Key to the Gulf of Mexico Species of Microphthalmus 



la. Neuropodia with simple and composite setae (Figure 28-6e-g), noto- 



podia with acicular and pectinate setae (Figure 28-6c,d) 



Microphthalmus sp. A, p. 28-9 



lb. Neuropodia with composite setae only, notopodia with pectinate 

 setae only 2 



2a. Median antenna absent; first few setigers with specialized neuro- 

 setae (Figure 28-8d) Microphthalmus hamosus, p. 28-11 



2b. Median antenna present; first few setigers without specialized 

 neurosetae 3 



3a. Body with distinct brown pigment bands anteriorly; dorsal cirri 

 not extending beyond neurosetae Microphthalmus sczelkowii* 



3b. Body with diffuse pigment; dorsal cirri extending well beyond 

 neurosetae (Figure 28-10a,b). . . . Microphthalmus sp. C, p. 28-13 



*Not found in BLM-OCS collections, but two specimens observed from 

 offshore Louisiana. 



Microphthalmus sp. A 



Figures 28-5, 6a-h 



MATERIAL EXAMINED: 

 Gulf of Mexico BLM-OCS: 

 MAFLA 2640C-2/78 (1 spec). 

 DESCRIPTION: 



Length, 2.6 mm; width, 0.4 mm. Body minute, slender, complete with 19 

 setigers and one achaetous preanal segment. Prostomium rounded, with 

 median antenna arising dorsally on posterior half. Antennae and palps 

 similar in length. Eyes absent. Nuchal organs as small, rounded lobes 

 along posterior margin of prostomium (Figure 28-6a). Tentacular cirri 

 filiform, all three tentacular segments distinct dorsally. Parapodia 

 subbiramous from setiger 1; notopodia poorly developed, with notosetae 

 arising from dorsal cirrophore. Dorsal cirri long, subulate. Neuropo- 

 dia with prolonged, digitiform acicular lobe and long, slender ventral 

 cirri (Figure 28-6b). Notosetae including one upper acicular spine 



28-9 



