FOREGUT ANATOMY AND CLASSIFICATION OF CONOIDEA 



153 



Table 4. Synapomorphies for interior nodes. Nodes numbered as 

 in Fig. 27. 



Node 



Synapomorphies (Character: state) 



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 



26 



27 



28 



29 



30 



31 



32 



33 



34 



35 



36 



37 



38 



7(1), 20(1), 35(0), 37(0), 38(1) 



13(1), 23(2), 24(1), 26(1) 



1(1), 3(1), 34(3), 38(3), 40(2) 



4(1), 14(1), 15(1), 29(1) 



25(1), 37(1) 



6(1), 16(1), 41(1) 



7(0), 23(0), 25(0) 



12(1) 



33(1), 43(1) 



7(2), 29(1) 



12(1) 



34(0), 40(0) 



14(1), 27(0), 43(0) 



7(1), 35(1) 



34(0), 37(2) 

 2(1), 38(2), 40(2) 

 22(1), 25(2), 32(1) 



20(0) 



2(1), 34(0) 



2(1), 14(1), 28(0) 



18(1) 



14(0), 35(1), 39(1), 42(1) 



7(1), 35(1) 



8(1), 34(0) 



20(0), 39(0) 



19(1), 36(1) 



28(0), 42(1) 



10(1), 11(1) 



6(1), 7(1), 14(1), 31(1) 



30(1), 31(2), 38(0) 



1(1), 14(1), 21(1), 39(1) 



38(3) 



4(1) 



5(1), 29(2), 39(0), 41(1) 



17(1), 40(0) 



1(0), 35(0) 



which are the only conoideans possessing five teeth in each 

 radular row. They also retain the connection of the radular 

 retractor muscle to the columellar muscle. Their distinctive 

 apomorphy is the possession of large, comb-like lateral teeth. 

 We have studied only three species in this group (the third 

 species identical to Clavus unizonalis) which are very similar 

 to each other. However, we note the very different hollow, 

 enrolled 'hypodermic-style' marginal teeth of lmaclava 

 (Shimek & Kohn, 1981) and the possible 'wishbone' margin- 

 als of Drillia roseola (McLean, 1971). Anatomical studies of 

 these taxa are needed to determine their status. 



All other conoideans are separated from the Drilliidae at 

 Node 2 by the loss of the radular retractor/columellar muscle 

 connection, by the loss of the lateral teeth and possession of 

 curved pointed marginal teeth. None of the non-drilliid taxa 

 that we have included in the cladistic analysis possess lateral 

 teeth, although what appear to be vestigial lateral teeth are 

 seen for example in Antiplanes (Kantor & Sysoev, 1991) and 

 a few other species. Also, it is possible that the broad central 

 teeth seen in Cochlespirinae may be formed by fusion of 

 lateral teeth. Another apomorphy at this node is the posses- 

 sion of a broad central tooth with a spine-like central cusp. 



Node 3 separates the Terebridae, with five apomorphies 

 including the possession of a rhynchodeal introvert and the 

 accessory proboscis structure. The Pervicaciinae (Node 4) are 

 separated from Hastula (representing the Terebrinae) by the 

 loss of the proboscis, the presence of extensible buccal lips, a 

 septum in the rhynchocoel (although this is present in some 

 Terebrinae) and the loss of the venom gland. 



Node 5 separates all other conoideans with two apomor- 

 phies namely the presence of wishbone marginal teeth and a 

 moderately long siphonal canal. The latter is a weak charac- 

 ter and although we consider the fomer to be a strong 

 character, some taxa in Clade 6 have solid teeth which PAUP 

 considers a reversal from the wishbone condition. 



Clade 6 comprises taxa with the epithelium of the posterior 

 part of the rhynchodeum continuous with that of the probos- 

 cis and with an elongated loop of oesophagus anterior to the 

 nerve ring. 



Clade 7 includes two taxa with solid marginal teeth and no 

 buccal tube sphincter and Toxiclionella which has hollow 

 teeth. PAUP treats the solid teeth as a reversal, but we think 

 that this is unlikely. However, it is possible that the 'flanges' 

 on the teeth of Strictispirinae may be modifications of a 

 second limb on the tooth. Toxiclionella and Strictispira are 

 grouped together at Node 8, because both have a buccal mass 

 situated at the distal end of the proboscis. However, Toxi- 

 clionella shares many characters with the Clavatulinae 

 (including the medio-lateral nucleus of the operculum), but 

 has a very different radula with hollow and barbed marginal 

 teeth firmly attached to the radular ribbon located in the 

 distal buccal mass. Although Toxiclionella tumida lacks a 

 central tooth, a clavatuline type central is known in T. elstoni 

 (Kilburn, 1985). Turricula nelliae (Node 12) shares many 

 apomorphies with clavatuline species and should be trans- 

 fered from the Cochlespirinae to the Clavatulinae. 



PAUP suggests that Funa and Vexitomina (Crassispirinae) 

 and Pilsbryspira (Zonulispirinae) are derived from the Clav- 

 atulinae. They share a number of characters, but Funa and 

 Vexitomina have distinctive wishbone teeth with one broad 

 flat limb and a small, thin, subsidiary limb. Pilsbryspira has 

 enrolled marginal teeth and a distal buccal mass. This type of 

 tooth could be derived by enrollment of the crassispirine type 

 of wishbone tooth. Both groups have an operculum with a 

 terminal nucleus which PAUP treats as a reversal from the 

 medio-lateral nucleus of the Clavatulinae. 



Lophiotoma and Polystira (Turrinae) (Node 16) have a 

 peripheral anal sinus and a posteriorly situated rhynchodeal 

 sphincter. Aforia has an accessory salivary gland and PAUP 

 treats this appearance as a reversal, the glands having already 

 been lost between the outgroup and the first node. However, 

 it is highly unlikely that these glands are regained once lost. 

 Accessory glands have a very patchy distribution amongst the 

 Conoidea (Conus, Benthofascis and some Clathurellinae) and 

 apart from their occurrence in some terebrids, Aforia is the 

 only 'lower' conoidean in which we have seen the glands. The 

 distribution of this character should become clearer as more 

 species are examined. Maybe significant, is the fact that 

 Aforia is the only other conoidean in which the multidigitate 

 osphradial leaflet typical of Conus has been found (Sysoev & 

 Kantor, 1988 fig. 2J). 



From Node 18 onwards are all the so-called 'higher' 

 conoideans, which in all our analyses form a monophyletic 

 group. The apomorphies which define this node are the 

 presence of a radula caecum for storage of detached radular 

 teeth, hollow, enrolled marginal teeth, loss of the radular 



