HUBBS and VVISN'ER REVISION OP THE SAURIES 



Tables. — Numbers of pectoral fin rays (both sides counted) and 

 of total anal and dorsal fin rays (including finletsl for the scom- 

 beresocid fishes. 



Fin 

 rays 



Scomberesox Cololabis Nanichthys Elassichthys 

 saurus ' saira simulans adocetus 



The much reduced size of Nanichthys and the 

 even more extreme dwarfing of Elassichthys 

 strongly support the hypothesis that they exhibit 

 neotenic or paedomorphic tendencies, certainly 

 dwarfism; we hold that they are not neotenic, in 

 the strict sense, but merely dwarfed. The reduced 

 numbers of gill rakers, pectoral rays, vertebrae 

 (Tables 2-5), scales, and procurrent caudal rays 

 provide confirmatory evidence (no marked differ- 

 ences were found in the numbers of dorsal and 

 anal rays, either in the main fin or in the finlets). 

 The loss of one ovary (or the complete fusion of the 



T.ABLE 4. — Numbers of vertebrae for the scomberesocid fishes. 



Number of Scomberesox Colotabis Nanichthys Elassichthys 



vertebrae saurus saira simulans adocetus 



54 

 55 

 56 

 57 

 58 

 59 

 60 

 61 

 62 

 63 

 64 

 65 

 66 

 67 

 68 

 69 

 70 



2 

 11 

 30 



46 



14 



74 



224 



186 



52 



6 



'Counts for the southern and northern subspecies are combined 



pair), and a tremendous decrease in the production 

 of ova, the more notable in Elassichthys, may well 

 be correlated with the dwarfing of the two new 

 genera (the ova, however, have not been notably 

 decreased in size). The less extreme dwarfing of 

 Nanichthys could be interpreted as reflecting the 

 larger size of its presumed progenitor, Scum- 

 hereso.x (Figure 1, Table 1). The concept of Na- 

 nichthys and Elassichthys being the respective de- 

 rivatives of Scomberesox and Cololabis could be 

 interpreted as being supported by their similar 

 beak structures (Figure 2). and by the common 

 occurrence of Scomberesox and Nanichthys in the 

 Atlantic and Indian Oceans and of Cololabis and 

 Elassichthys in the Pacific, north of the range in 

 that ocean of Scomberesox. 



Herein we describe, discuss, and differentiate 

 the two new dwarfed genera, Nanichthys and 

 Elassichthys, and the new species A^. simulans, 

 distinguish the Southern Hemisphere population 

 of Scomberesox as a subspecies, fo.r which the 



T.^BLE 5. — Correlated counts of precaudal and caudal vertebrae of the four genera of Scomberesocidae. Counts not otherwise marked 

 represent Ehssichthys; counts in italics refer to /Nanichthys; counts in parentheses represent Cololabis; and counts in bold face type 

 refer to Scomberesox. 



'Counts for the southern and northern subspecies are combined. 



527 



