ANATOMY AND SYSTEMATICS OF CARDIOLUCINA 



119 



§> 



c 

 .<« 



<n q. 



Si Z: v, 



v s 2 





.<a 



3 







V) 







<0 



c 



5. 



to 



§ 



§ 



5 







3 



.o- 



4-» 



in 



a 



T3 



3 



Q. 



VI 



CO 



o- 





outgroup 





n 



2 



Q. 



3 

 U 





<n 



18 



3 



TO 



C 



u 



4) 



9 



8 



7 



5 

 4 



2 





1 





Fig. 29 Strict consensus tree of Cardiolucina species derived from two equally parsimonious trees. Outgroup is Parvilucina tenuisculpta. Character state 

 changes at numbered internal branches. Branch l : char. I , state 2>1 ; char. 3 state 3>0; char. 6 state 2>l . Branch 2: char. 3 state 0>2; char. 8 state 0>1 ; 

 char. 1 1 state 0>1. Branch 3: char. 1 1 state 1>2. Branch 4: char. 7 state 1>0. Branch 5: char. 4 state 0>1; char.5 state 0>1; char. 6 state 1>0; char. 12 state 

 2>0. Branch 6: char. 9 state 0>1. Branch 7: char. 1 state 1>0; char. 2 state 0>2. Branch 8: char. 12 state 2>1. Branch 9: char. 2 state 2>1. Branch 10: 

 char. 10 state 0>1. 



Table 1. Characters and character state codings used in the phylogenetic analysis. 



1. Posterior sulcus. This is an indentation in the posterior shell seen on 

 the outer surface extending from the umbo to the shell margin. It is present 

 in all Cardiolucina species, deeply incised in some (Fig. 20d), shallow in 

 others (Fig. 2a) and weak and poorly-defined in the outgroup. 

 States: - deep prominent;! - shallow; 2 - weak 



2. Anterior sulcus. This is a similar indentation at the anterior end of the 

 shell. This is absent in some species, but where present (Fig. 20) never as 

 prominent as the posterior sulcus. 



States: - absent; 1 - narrow; 2 - broad 



3. Lunule. Many species have a heart-shaped, shallow lunule (Fig. 20c) , 

 but in C. eucosmia it is deeply excavated. In other species the lunule is 

 very small and tucked under beak (Fig. 2) and in the outgroup it is 

 lanceolate. 



States: - shallow, heart-shaped; 1 - deeply excavated; 2 - tiny under 

 umbo; 3 - thin lanceolate 



4. Radial ribs - number 



States: - less than 20; 1 



more than 20 



5. Radial rib - shape 



Some species have prominent ribs with straight sides and separated by 

 broad interspaces (Figs. 2,3). In others, the ribs are closer together with 

 low rounded profiles and narrow interspaces (Figs. 7,10). 

 States: - rounded, narrow interspaces; 1 - straight-sided broad interspaces 



6. Radial rib intersection with concentrics. 



In some species, ribs appear to cross concentric lamellae without 

 interruption (Fig. 2d) whilst in others the ribs terminate at the intersection 

 with major concentric lamellae (Fig. 7d). In the outgroup the radial ribs 

 are extremely weak. 



States: - strong, cross concentrics 

 very weak 



weak, terminate at concentrics; 2 - 



7. Concentric lamellae - number 



Concentric lamellae are a prominent feature of many Cardiolucina species. 

 States: - less than 20; 1 - more than 20 



8. Shape of anterior cardinal tooth in left valve 



The majority of species have a triangular wedge shaped tooth (Fig. 18b) 



but in some species the anterior cardinal is a hook-shaped projection (Fig. 



3c). 



States: - wedge; 1 - hooked 



9. Posterior cardinal of left valve 



Most species have a relatively thin tooth (Fig. 7c ), but in C. pisiformis , 

 for example, it is much thicker (Fig. 14c ). 

 States: - thin; 1 - thick 



10. Denticles on cardinal teeth 



This refers to small denticles seen at high magnification along the edges of 

 the posterior cardinal (Fig. 1 2d). 

 States: 0- absent; 1 - present 



1 1 . Hinge buttress 



The hinge may be projected ventrally below the cardinal teeth to form a 



rounded buttress (Fig 3c). 



States: - absent; 1 - slight; 2 - prominent 



12. Margin crenulations - number 



These are seen on the internal ventral margin of shell. These were counted 



around the shell margin, fine beading not included. 



States: - coarse (n = 10-20); 1 - medium (n = 21-30); 2 - fine (31 + ). 



