BASAL LAOPHONTID EVOLUTION 



73 



process which was not illustrated in the lateral habitus view, possi- 

 bly indicating that the author had indeed observed but incorrectly 

 figured the cephalic pores. We have re-examined Nicholls' slide 

 material and found remnants of the cephalic shield, confirming the 

 presence of both anterodorsal and anteroventral pores as in Esola. 

 Scrutinous observation failed to reveal any such structures on the 

 genital somite. 



With only two records known, M. longiseta appears to display a 

 remarkably disjunct distribution. Topotype material from Brazil is 

 required to confirm whether the morphometric discrepancies in 

 Jakobi's description result from imperfect observation or reflect 

 species level differences between the Brazilian and Australian popu- 

 lations. 



Genus Archilaophonte Willen, 1995 



Diagnosis. Laophontidae. Body elongate and slender; cephalo- 

 thorax slightly wider than rest of body; posterolateral corners of 9 

 genital double-somite and second abdominal somites not laterally or 

 backwardly produced. Integument of cephalothorax and body somites 

 with dense pattern of spinules and setules; cup-shaped pores on 

 cephalothorax, genital (double-)somite and caudal rami absent. 



Rostrum very large, partly delimited at base. Integumental cup- 

 shaped pores absent. Anal operculum spinulose. Caudal rami very 

 long, cylindrical with posterior halves diverging. 



Sexual dimorphism in body shape, antennule, P3 endopod, P5, P6 

 and in genital segmentation. 



Antennules short; 6-segmented in 9, subchirocer and 7-seg- 

 mentedin d;posterior margin of segment 1 with small blunt process, 

 that of segment 2 with distinct spinous process; with aesthetasc on 

 segment 4 ( 9) or 5 ( 8) and as part of apical acrothek on distal 

 segment; segment 6 of <5 not particularly modified; proximal 

 aesthetasc fused to 1 seta. Antenna with 4 setae on exopod; allobasis 

 with abexopodal seta. Mandible with biramous palp bearing discrete 

 1 -segmented rami; basis with 1 lateral seta, exopod with 1, endopod 

 with 3 apical setae. Maxillule with seta at base of exopod. Maxilla 

 with 3 endites on syncoxa; endopod represented by 4 setae. 

 Maxilliped moderately slender; with 3 setae on syncoxa; endopodal 

 claw long and slender. 



PI with 2-segmented exopod bearing 5 setae on exp-2 and 

 elongate endopod; enp- 1 with inner seta, enp-2 with minute seta and 

 long, slender claw. P2-P4 with 3-segmented exopods and 2-seg- 

 mented endopods. P2 basis with normally developed outer spine. 

 Outer spine of P4 enp-2 not very long. P3 endopod 8 3-segmented; 

 enp-2 with inner seta and very long, slender, sigmoid apophysis. P3 

 exopod 8 weakly modified with exp-3 being shorter than in 9. 

 Armature formula as follows: 



Exopod 



Endopod 



P2 

 P3 

 P4 



0.1.123 

 0.1.223 

 0.1.223 



1.121 

 1.321 

 1.221 



[cJ: 1.1.220] 



P5 9 with separate rami; exopod large and elongate, with 6 setae/ 

 spines; baseoendopod well developed, with 5 setae/spines. P5 8 

 with trapezoid endopodal lobe bearing 2 long setae; exopod rectan- 

 gular, with 1 inner, 1 outer and 2 apical setae/spines. 



P6 9 forming opercula closing off paired genital apertures; with 2 

 long setae. P6 8 asymmetrical; membranous flaps with 1 tiny seta. 



TYPE AND ONLY SPECIES. Archilaophonte maxima Willen, 1995 

 [by monotypy]. 



Type locality. 72°52.3' S, 19°34.7' W, Weddell Sea, Antarctic; 

 495 m depth. 



REMARKS. Willen (1995) described A maxima in great detail; the 

 slight sexual dimorphism illustrated for the P3 exopod was not 

 mentioned in the text. The species is known from two localities in 

 the Weddell Sea. 



Genus Applanola gen. nov. 



DIAGNOSIS. Laophontidae. Body strongly depressed and com- 

 paratively short; cephalothorax much wider than rest of body; 

 posterolateral corners of 9 genital double-somite and second ab- 

 dominal somites laterally and backwardly produced. Integument of 

 cephalothorax and body somites with dense pattern of spinules and 

 setules. Rostrum very large, partly delimited at base. Four pairs of 

 integumental cup-shaped pores present: anterodorsally on 

 cephalothorax, near ventrolateral margins of cephalic shield, later- 

 ally on genital (8) or genital double-somite (9) and ventrally on 

 caudal rami. Anal operculum spinulose. Caudal rami short, squar- 

 ish. 



Sexual dimorphism in body shape, antennule, P2-P4 exopods, P3 

 endopod, P5, P6 and in genital segmentation. 



Antennules short; 6-segmented in 9, subchirocer and 7-seg- 

 mentedin 6*; segments 1-2 without distinct processes; with aesthetasc 

 on segment 4 ( 9) or 5 {8) and as part of apical acrothek on distal 

 segment; segment 6 of 8 with large bilobate outgrowth dorsally; 

 proximal aesthetasc fused basally to 2 setae. Antenna with 4 setae on 

 exopod; allobasis with abexopodal seta. Labrum with distal patch of 

 long spinules. Mandible with elongate 1 -segmented palp with 1 

 lateral and 3 apical setae. Maxillule with elongate defined exopod. 

 Maxilla with 3 endites on syncoxa; endopod represented by 4 setae. 

 Maxilliped large and robust; with 2 setae on syncoxa; endopodal 

 claw relatively short. 



PI with 2-segmented exopod bearing 5 setae on exp-2 and robust 

 endopod; enp- 1 without inner seta, enp-2 with minute seta and short, 

 strongly curved claw. P2-P4 with 3-segmented exopods and 2- 

 segmented endopods. P2 basis with very long outer spine. Outer 

 spine of P4 enp-2 very long. P3 endopod 8 3-segmented; enp-2 with 

 inner seta and outer dentate apophysis. P3 exopod 8 strongly 

 developed with modified outer and distal spines on exp-3; exopods 

 of P2 and P4 similar in size to 9 but with stronger ornamentation on 

 outer spines. Armature formula as follows: 



Exopod 



Endopod 



P2 

 P3 

 P4 



0.1.123 

 0.1.223 

 0.1.223 



1.220 

 1.321 

 1.221 



[6: 1.1.220] 



P5 9 with separate rami; exopod elongate, with 6 setae/spines; 

 baseoendopod slightly developed, with 4 setae/spines. P5 8 without 

 endopodal lobe; exopod short, with 1 inner, 2 apical and 2 outer 

 setae/spines. 



P6 9 forming opercula closing off paired genital apertures; with 

 one seta and 2 small processes at outer corner. P6 8 asymmetrical; 

 membranous flaps without armature. 



TYPE AND ONLY SPECIES. Laophonte hirsuta Thompson & A. 

 Scott, 1903 = Applanola hirsuta (Thompson & A. Scott, 1903) 

 comb. nov. 



Etymology. The generic name is derived from the Latin ad (to) 

 and planatus (flattened), and alludes to the dorsoventrally depressed 

 body. Gender: feminine. 



