118 



L. BOUCK, D. THISTLE AND R. HUYS 



Table 2 Characters used in phylogenetic analysis. Apomorphic character states are referred to in square brackets. Characters 5-7 are multistate characters. 



9 



10 

 11 

 12 

 13 

 14 

 15 

 16 

 17 

 18 

 19 

 20 

 21 

 22 

 23 

 24 

 25 



Antennule 9 8-segmented [7-segmented, segments 6 and 7 fused] 



Antennule 9 with only setiform elements on segments 3, 4 and 5 [segment 3 with 2 and segments 4—5 with 1 strong, modified spine] 



Antennule 9 segment 6 (or homologous portion in 6- or 7-segmented antennule) without enlarged spines [with 2 enlarged pectinate or pinnate spines] 



Antennule 9 with all elements naked (except for pinnate spines referred to in character 3) [with pinnate or plumose setae on segments 1-6] 



Antennary exopod 3-segmented [state 1: 2-segmented; state 2: 1 -segmented] 



Antennary exopod with total of 5 setae (2 on exp-1, 3 on exp-3; exopod 3-segmented) [state 1: 2 on exp-1, 2 on exp-2 and exopod 2-segmented; 



state 2: total of 2 setae on single segment] 



Maxilla with 5 setae on praecoxal endite [state 1: 4 setae; state 2: 3 setae] 



PI exp-3 with 2 geniculate (hinged) and 3 simple claws [with 2 geniculate and 2 simple claws] 



PI enp-1 with long inner seta [without] 



P2 enp-3 with 2 inner setae [with 1 inner seta] 



P3 enp-2 with inner seta [without] 



P3 enp-3 with 3 inner setae [with 2 inner setae] 



P4 exp-3 with 3 outer spines in 9 [with 2 outer spines in 9 , 3 incf ] 



P4 endopod 3-segmented [2-segmented; enp-2 and -3 fused] 



P4 enp-2 (or homologous portion in 2-segmented endopod) with inner seta [without inner seta] 



P4 enp-3 (or homologous portion in 2-segmented endopod) with 2 inner setae [with 1 inner seta] 



P5 exopod oval or elongate in both sexes [round] 



P5 9 endopodal lobe expressed [completely lost] 



P5 9 endopodal lobe inner seta not distinctly shorter than other endopodal elements [rudimentary] 



P5 9 endopodal lobe 3rd and 4th setae well developed [much shorter than others] 



Antennule cf segment 3 without transformed elements [with modified spine] 



P2 enp-2cf with apophysis [secondarily lost] 



P2 enp-2cf inner element setiform, not sexually dimorphic [modified into stout spine, distinctly shorter than in 9 ] 



P2 enp-3 outer spine articulating with segment [fused to segment] 



P3 enp-2cf outer distal coiner not attenuated [attenuated] 



Table 3 Character data matrix. Characters listed in Table 2 are scored using the multistate system: = ancestral (plesiomorphic) state, 1 = derived 

 (apomorphic) state, 2 = further derived state, ? = missing data, indicating that the character state is either unknown or unconfirmed. 



Character 



1 



2 



3 



4 



5 



6 



7 



8 



9 



10 



11 



12 



13 



14 



15 



16 



17 



18 



19 



20 



21 



22 



23 



24 



25 



arenicolus 















1 



2 



2 



1 

























1 















1 























areolatus 



1 



1 



1 







2 



2 



2 























1 



1 















1 

















biarticulatus 



















1 



1 



1 

































1 



1 

















1 







cookorum 



















1 



1 



1 















1 















1 



1 













1 



1 



1 



kirstenae 



















1 



1 



1 















1 

















1 



1 













1 



1 



1 



limigenus 



1 



1 



1 



? 



2 



2 



7 







1 















1 



1 















7 





7 



? 



7 



paranaguaensis 



1 



1 



1 



? 



2 



2 



? 







1 















1 



1 















7 





7 



7 



7 



Septimus 















1 



2 



2 



1 























1 















1 





















sextus 



1 



1 



1 







2 



2 



2 























1 



1 















1 

















shulenbergeri 



1 



1 



1 







2 



2 



2 







1 















1 



1 















1 

















stammeri 



1 



1 



1 



7 



2 



2 



7 







1 















1 



1 















7 



7 



7 



7 



7 



PERISSOCOPE 































































































1 



1 



cinctus 



1 















2 



2 



7 



1 



1 



































1 



? 



7 



? 



7 



7 



? 



7 



of the Thompsonulidae (Huys & Gee, 1990) and Tetragonicipitidae 

 (Kunz, 1984) sexual dimorphism involves the loss of elements in the 

 male, whereas in species of Huntemannia Poppe an increase in the 

 number of elements has been reported (Wilson, 1958; Geddes, 

 1968b). Two new species from the Gulf of Mexico {kirstenae, 

 cookorum) show 2 outer spines on the distal exopod segment of P4 

 in the female and a supernumerary spine in the male. All other 

 species of the Zausodes complex possess 3 spines in both sexes. 



(14) Segmentation P4 endopod 



Only three speciesof the Zausodes complex (i.e. arenicolus, kirstenae 

 and cinctus) have retained the 3-segmented condition of the P4 

 endopod. In all other species the middle and distal segments have 

 failed to separate, resulting in a 2-segmented ramus. Lang (1965) 

 refused to split up Zausodes on the basis of P4 endopod segmentation 

 since for many other characters close congruence was found between 

 species with different segmentation. Lang assumed that the 2- 



segmented state had arisen convergently and pointed out that the 

 original division of the distal segment in Z. sextus is still indicated by 

 a dentiform notch along the outer margin. An incomplete surface 

 suture was also found in Z. areolatus (Fig. 1 1C), suggesting that the 

 P4 endopod segmentation is probably an evolutionary labile character. 



(15) Armature P4 enp-2 



Most harpacticid genera displaying a 3-segmented P4 endopod 

 possess an inner seta on the middle segment. This seta has been lost 

 in the Zausodes complex (except Z. cinctus), including the two 

 species in which the middle segment is still separated (kirstenae, 

 arenicolus). 



(16) Armature P4 enp-3 



The maximum number of inner setae on the distal (enp-3) endopod 

 segment of P4 in any species of the Harpacticidae is two. This 

 number is found in most members of the family, including some (but 



