244 
PACIFIC SCIENCE, Vol. VII, April, 1953 
ably similar to an elongate paralepidid or 
anotopterid, but again the head bones are 
inadequately known, and the resemblance 
may be only superficial. 
The first definite representative of a recent 
alepisauroid family appears in the Eocene on 
the basis of the paralepidid genus Holosteus 
Agassiz. Scopeloides Wettstein from the Oligo- 
cene might be a scopelarchid. A fossil Alepi- 
saurus has been discovered in the Miocene of 
Europe. The genus Apateodus Woodward of 
the Cretaceous family Enchodontidae has a 
dentition similar to the Alepisauridae, and 
several authors have suggested a close rela- 
tionship. 
The Paralepididae are the best known ini. 
omous group found in the Tertiary, compris- 
ing six fossil genera {Paralepis Cuvier, Tros- 
!/////! Jordan, Lestkbthys ]ord3.a, DrmysJordd.n, 
Holosteus Agassiz, and Parascopelus Sauvage) 
and approximately 10 species. The references 
to fossil members of the genus Sudis belong 
with Paralepis. The paralepidids from the Mio- 
cene diatom beds at Lompoc, California, and 
Parascopelus from the Miocene of Europe ap- 
pear to provide a complete intergradation 
between this family and the Chlorophthalmi- 
dae. Thus it would appear that the suborder 
Alepisauroidea had not become fully differ- 
entiated until relatively recently. This is cor- 
roborated by the degree of relationships of 
the recent forms. The family Paralepididae is 
distinctly the most generalized group in the 
suborder Alepisauroidea, and particularly the 
genus Magnisudis shows a revealing number 
of similarities to chlorophthalmids. The other 
alepisauroid families (Alepisauridae, Anotop- 
teridae, Scopelarchidae, Evermannellidae, 
Omosudidae) are much more specialized and 
probably were well differentiated by the begin- 
ning of the Tertiary. The Dercetidae resemble 
Anotopteridae in which the size of the dorsal 
fin is between that of the Paralepididae and 
the Alepisauridae. If there is a relationship 
here, it indicates that these groups were high- 
ly evolved even by the Upper Cretaceous. 
Despite the fact that the Miocene fossils 
seem to show no distinction between the 
Chlorophthalmidae and Paralepididae, the 
Eocene, Pliocene, and certain Miocene forms 
are so similar to recent paralepidid genera 
that only minor differences are evident in the 
osteology. 
Among recent groups the Paralepididae are 
most closely related to the Anotopteridae. 
They both have the same general proportions, 
essentially similar osteology, the same pecu- 
liar cartilaginous development of the jaws 
which is found in these two families alone 
in the order, and a good number of other 
similarities. In turn, the Anotopteridae are 
very closely related to the highly specialized 
Alepisauridae. There are secondary modifica- 
tions of the suspensorium that separate the 
Anotopteridae from the Alepisauridae, but the 
cranial osteology and dentition is very similar, 
the skin has exactly the same pore system in 
the adults of both families, which is found 
only in the adults of these two families in the 
order, and the proportions are closely similar. 
Therefore, these three families appear to repre- 
sent one line of evolution arising from a 
chlorophthalmid-like ancestor, with the Ale- 
pisauridae representing the most highly spe- 
cialized end-point. On the basis of their 
postlarval development and morphology the 
Scopelarchidae, Evermannellidae, and Omo- 
sudidae appear to have branched off from the 
alepisaurid line of evolution in various direc- 
tions and each represents its own unique end- 
point of evolution. Among these three fami- 
lies the Scopelarchidae are closest to the 
Chlorophthalmidae, and the Omosudidae are 
most closely related to the Alepisauridae. ! 
The Alepisauroidea seems to be a valid 
suborder despite the fact that at least one of 
its families (Paralepididae) may have become i 
separated from the Chlorophthalmidae of the 
suborder Myctophoidea (= Aulopodoidea 
Gill, 1893) as late as the Miocene or Pliocene, j 
In fact, future research may very well reveal ^ 
intermediate recent forms between the chlo- ! 
rophthalmid line and the Paralepididae. If this 1 
