A REVIEW OF THE LANTERNFISH GENUS Taaningkhthys (FAMILY 

 MYCTOPHIDAE) WITH THE DESCRIPTION OF A NEW SPECIES 



Brent Davy^ 



ABSTRACT 



The genus Taaningichthys includes three known species, one of which is here described as new. 



The species of the genus Taaningichthys do not appear to perform daily vertical migrations. Evidence 

 indicates vertical stratification of juveniles and adults. 



Although photophores and lateral line are reduced, the species of Taaningichthys possess very large 

 eyes which may be related to capture of luminescent prey. 



Otoliths of all three species have been examined and found to be taxonomically important. 



Bolin (1959) erected the genus Taaningichthys 

 to include two species, T. hathyphilus and T. mi- 

 nimus, previously placed in the genus Lampade- 

 na by Taning (1928). The main characters 

 which distinguish Taaningichthys from Lampa- 

 dena are: (1) the origin of the dorsal fin in 

 Taaningichthys is clearly behind the base of the 

 pelvic fins; (2) the development in Taaningich- 

 thys of a crescent of white tissue' on the pos- 

 terior half of the iris, although a similar white 

 (luminous?) crescent is present on the dorsal 

 portion of the iris in Lampadena chavesi (Naf- 

 paktitis and Paxton, 1968); (3) the presence 

 of a single SAO, or none, in Taaningichthys 

 (always three SAO in Lampadena) ; (4) re- 

 duced dentition and lateral line in Taaningich- 

 thys. 



Taaningichthys may be distinguished from all 

 other myctophid genera by the combination of 

 the white crescent of tissue on the posterior half 

 of the iris, the undivided luminescent caudal 

 glands, and the single or altogether absent SAO. 



Berry and Perkins (1966) reported what they 

 thought to be a third form of Taaningichthys 

 apparently without photophores. Following the 

 capture of a number of specimens of this form 



^ Department of Biological Sciences, Allan Hancock 

 Foundation, University of Southern California, Los An- 

 geles, Calif. 90007. 



"This tissue is not visible until some time after preser- 

 vation and is hardly distinguishable in specimens initially 

 frozen and then preserved. 



by the RV Velero IV of the University of 

 Southern California and the examination of con- 

 siderable material made available to me by nu- 

 merous institutions around the world, I felt that 

 a review of the genus was appropriate. 



MATERIALS AND METHODS 



Members of the genus Taaningichthys are 

 deep-dwelling, fragile myctophids, easily dam- 

 aged by the net. Scales are readily lost, and 

 damage to the bones of the snout, upper jaw, 

 and operculum is very common. Consequently, 

 measurement of jaw, head, and snout length is 

 often very difficult if at all possible. The follow- 

 ing measurements were taken on the best pre- 

 served specimens: Eye diameter (ED) — hori- 

 zontal distance across the orbit; jaw length ( JL) 

 — length of premaxillary; predorsal (Pre D) — 

 anterior tip of premaxillary to base of anterior- 

 most ray of dorsal fin ; pre ventral (Pre V) — an- 

 terior tip of premaxillary to base of anteriormost 

 ray of ventral fin; preanal (Pre A) — anterior tip 

 of premaxillary to base of anteriormost ray of 

 anal fin; prepectoral (Pre P) — anterior tip of 

 premaxillary to base of anteriormost ray of pec- 

 toral fin; preadipose (Pre Ad) — anterior tip of 

 premaxillary to posterior end of base of adipose 

 fin; length of supra- and infracaudal luminous 

 glands — length of exposed luminous tissue only; 

 anal-infracaudal distance — anterior tip of 



Manuscript accepted July 1971. 



FISHERY BULLETIN: VOL. 70, NO. 1, 1972. 



67 



