WILLIAMS and CHILD: COMPARISONS OF SOME BOX CRABS 



granules clustered laterally; telson subtriang^lar. 

 Male pleopod 1 rather stout, slightly curved and con- 

 ically elongate, tapering to narrow distal opening 

 with nearby cluster of minute horny spinules; 

 pleopod 2 with slender stylet divided into 2 parts, 

 gently curved proximal part stronger than distal 

 part curved mesially upon itself as a crook, distal 

 half of crook extending beyond tip of pleopod 1 . 



Measurements in -mm.— Carapace: smallest o* 

 length 14.4, maximum anterior width 15.8, max- 

 imum width across winglike projections 15.4; largest 

 0-, same 35.1, 42.3, 44.8; smallest 9, same 10.7, 11.5, 

 11.4; largest 9, same 29.7, 34.5, 35.7. 



Known range.— North Carolina to Florida, around 

 Gulf of Mexico, Leeward Islands to off Venezuela, 

 13-238 m (see Powers 1977 in part). 



Remarks.— Milne Edwards's Calappa angusta 

 1880 has been generically misplaced. The next avail- 

 able name for the species is Calappa saussurei tor- 

 tugae Rathbun 1933, raised to full specific rank. 



The young of C. tortugae have long been regarded 

 as having the greatest carapace width anterior to 

 the winglike posterolateral projections. That is con- 

 firmed by measurements of young individuals noted 

 above, but measurement of a series ranging from 

 juvenile to adult indicates that the winglike postero- 

 lateral projections quickly become the widest part 

 of the carapace as growth progresses, as is true of 

 Calappa in general. Another way of expressing this 

 width is to compare it wdth the interorbital distance. 

 Interorbital distance expressed as a percent of max- 

 imum span across the posterolateral winglike pro- 

 jections is plotted for measured samples in Figure 

 2A {N = 71, X = 0.347, SD = 0.039). The eyes of 

 C. tortugae are relatively smaller and the orbits 

 more elevated than are those of species belonging 

 to either Paraeyclois or Cyclozodion new genus, and 

 it is clear that the indicated ratio lies largely beyond 

 that for these species, although it is comparable to 

 that computed for a sample of C. saussurei Rathbun 

 1898 available in the USNM (Fig. 2B, TV = 14, x 

 = 0.297, SD = 0.030, juveniles excluded). That sam- 

 ple contains a disproportionate number of very small 

 juveniles; therefore it is useful to compute two ratios 

 for that species, one that excludes the juveniles and 

 one that includes them (Fig. 2C, N = 21, x = 

 0.297, SD = 0.131). These two species oi Calappa 

 are similar enough to be regarded as a geminate pair 

 from either side of the Central American land mass, 

 as implied by Rathbun's descriptions. The chief dif- 

 ference is that C. saussurei has a much more coarse- 



ly and uniformly tuberculate extensor face on the 

 palms of the chelae than does C. tortugae. 



Cyclozodion new genus 



Diagnosis.— Carapace slightly wider than long and 

 moderately convex; front narrow and trilobate; me- 

 dian lobe rounded and much broader than lateral 

 lobes; without lateral epibranchial spine or tooth; 

 anterolateral margins regularly arcuate and entire 

 or lightly crenulate, broadest span anterior to junc- 

 ture w\t\\ posterolateral margin; each posterolateral 

 margin bearing strongly spiniferous winglike pro- 

 jection, width between principal spines on latter less 

 than greatest width of carapace, axis of principal 

 spine on lobe diverging from midsagittal line at 

 angle of about 40°. 



Eyes large, peduncles short, robust, closely en- 

 cased in oval orbits scarcely raised above surround- 

 ing area; interorbital distance 0.40-0.70 (0.80 in 

 smallest juveniles) of span between tips of principal 

 spines on posterolateral margin. Antennules folding 

 obliquely; antennae with quadrate basal article not 

 reaching frontal margin, flagellum very short. Outer 

 maxillipeds with ischium longer than broad, longer 

 than distally truncate merus with its anterointernal 

 angle distinctly notched. Pereopods 2-5 spineless. 



Type species.— Cyclozodion angustum (A. Milne 

 Edwards 1880). 



Etymology.— From the Greek "cyclo", round, and 

 "zodion", a small carved figure, for the shape of the 

 carapace. The gender is neuter. 



Remarks.— Two small species fit between Calap- 

 pa and Paraeyclois. These species have the orbital 

 characteristics of Paraeyclois. They have postero- 

 lateral spines that cover a narrower span than do 

 those of Calappa, but in general shape they resem- 

 ble some juveniles of that genus. The two small 

 species could almost be cited as examples of 

 brachyuran neoteny, for they seemingly maintain 

 a juvenile Calappa-like carapace facies while attain- 

 ing sexual maturity. We are faced with the pros- 

 pect of further splitting the family by introducing 

 a new genus to contain these two species, or broad- 

 ening the concept of Paraeyclois to contain them. 

 However, lack of any spines on the pereopods and 

 shape of the proximolateral ridge on the extensor 

 face of the cheliped palms, to point out only two 

 features, clearly set them apart from Paraeyclois. 

 Rathbun (1937) and others perhaps unconsciously 

 took the alternate route of accommodating them in 



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