FISHERY BULLETIN: VOL. 72, NO. 3 



P: 



^'X 



T-' 



t<AW«ii.i.-rji.i^VifcS;i;C«iifvlo;-. 



a 



b _ 



Figure 23. — Female, left gonopore and portion of thoracic sternites IV- VII: a.,Callinectes latimanus Rathbun, Plage de Pointe Noire, 

 Congo; b, C. sapidus Rathbun, typical form, USNM 30567, Cameron, La.; c, C. sapidus Rathbun, acutidens form, USNM 99848, Roca 

 Arroyo Balizas [= Arroyo de Valizes?], Uruguay. Scales = 1 mm. 



Measurements of elements in the broad apron- 

 shaped abdomen of sexually mature females in- 

 cluded: 



13. 



14. 

 15. 

 16. 

 17. 

 18. 

 19. 



20* 

 21* 



Greatest width of segment 2. 



Greatest width of segment 3. 



Greatest width of segment 5. 



Median length of segment 5. 



Greatest width of segment 6. 



Median length of segment 6. 



Median length of segment 3 (proximal 



edge) to tip of telson. 



Length of telson. 



Width of telson. 



Analysis of selected nonsexual characters . — 

 Study showed that some of these measurements 

 were more valuable than others at the specific 

 level and 11 (marked with asterisks), generally 

 considered useful in verbal description, were 

 chosen for cluster analysis. Unfortunately, they 

 neither clustered as species nor as species groups 

 when analyzed. Results indicated that specific 

 morphological differences in this genus are based 

 on characters other than, or in addition to, those 

 measured and analyzed in this test. Measure- 



ments therefore were judged to have limited value 

 in identification. 



This finding is supported strongly by evidence 

 other than results of the attempt at cluster 

 analysis. Female Callinectes attain sexual matur- 

 ity in a terminal metamorphic molt. Males attain 

 an adult conformation at sexual maturity but may 

 continue to molt at reduced frequency. Van Engel 

 (1958) and others have shown that C. sapidus 

 females molt 18 to 20 times in attaining maturity, 

 males 18 or 19 before becoming mature and 3 or 4 

 times beyond that stage. The range of variation in 

 number of molts may be much greater than this, 

 for both dwarf and giant sexually mature indi- 

 viduals are known. Allometric changes accen- 

 tuated at the two ends of this continuum attest to 

 wide variability in form. Estevez (1972) em- 

 phasized variability in C. arcuatus and C. toxotes. 

 Tables 1 and 2 show means, standard devia- 

 tion, and sample size for selected characters from 

 adult male and female Callinectes species. For 

 almost all species the coefficient of variation 

 ( V = lOOs/x ) IS high for all characters shown, an 

 indication that morphometrically there is great 

 variation in the group. Simpson, Roe, and Lewon- 

 tin ( 1960:91 ) stated that V values greater than 10 



712 



