MARDSTE GAMMARIDEAN AMPHIPODA 



171 



Even the type-genus, Calliopius, has enlarged gnathopods, not 

 typical of the remaining members of the family. Extremes of variation 

 are shown in a group of gnathopodal figures presented herein. 



Apherusa, Bouvierella, Calliopiella, Halirages, and Haliragoides 

 are often very difficult to separate. Their type-species are easily dis- 

 tinguished by conditions of lower lip, anteroventral cephalic corners, 

 coxa 1 and accessory flagella, but those characters are highly variable 

 among other species of the five genera. 



Gurjanova (1962) has pointed out the unusual character of Sancho 

 and Chosroes. They have broadly vaulted, extremely depressed 

 bodies and heads and splayed coxae like those of Phliantidae but 

 they also have subfossorial pereopods and gnathopod 1 like that 

 of fossorial families Phoxocephalidae, Haustoriidae, and Oedicerotidae. 



Figure 73. — -Calliopiidae: Gnathopod 2: a, Sancho platynoius Stebbing (1897); b, Clarencia 

 chelata K. H. Barnard (1932); c, Stenopleura atlantica Stebbing (1888); d, Cleippides 

 bicuspis Stephensen (Gurjanova, 1951); e, Atylopsis dentatus Stebbing 



The mouthparts of both genera have a distinct look of the Oedi- 

 cerotidae. Neither genus has the fully developed pereopod 5 nor 

 elongate peduncle of uropod 3 found in the Oedicerotidae and Chosroes 

 has an elongate telson. Gnathopod 2 of Sancho distantly resembles 

 that of the phoxocephalid Joubinella (and various eusirids) ; and since 

 Phoxocephalidae and Haustoriidae seem to have strong affinities one 

 might consider Sancho to be an aberrant member of the Haustoriidae, 

 were it not for the uncharacteristic short peduncle of antenna 1, the 

 large male gnathopod 2, and the shortened outer rami of the uropods. 

 The conditions of the telson and pereopod 5 exclude the genera from 

 the Phoxocephalidae. But the short outer rami of the uropods of 

 Sancho and Chosroes like those of the Calliopiidae and Eusiridae 

 are not characteristic of the fossorial families. Probably a new family 



285-135 O - 69 - 12 



