Chernova and Stein: A new species of Psednos from the western North Atlantic Ocean 



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Table 1 



Counts and proportions for the holotype and paratype of Psednos rossi new species. Proportions are in % of standard length (SL) 

 followed by % head length (HL, in parentheses). 



Vertebrae 



Dorsal-fin rays 



Anal-fin rays 



Pectoral-fin rays 



Caudal-fin rays 



Gill rakers 



Head length 



Head width 



Head depth 



Body depth 



Body depth at anal-fin origin 



Predorsal-fin length 



Preanal-fin length 



Mandible to anus 



Anus to anal fin origin 



Upper pectoral-fin lobe length 



Pectoral-fin notch ray length 



Lower pectoral-fin lobe length 



Eye diameter 



Snout length 



Interorbital width 



Postocular head length 



Upper jaw length 



Lower jaw length 



Gill opening length 



Opercle length 



USNM 372727 

 Paratype 51.8 mm SL 



42 

 33 



15 [L, R] 

 6 

 10 



29.9 



13.5(45.2) 

 17.4(58.2) 

 25.1(83.9) 

 17.0(56.8) 

 26.6(89.0) 

 48.3(161.5) 

 36.7(122.7) 

 21.2(70.9) 

 13.5(45.2) 



5.8(19.4) 

 7.7(25.8) 

 11.2(37.4) 

 19.3(64.5) 

 12.5(41.8) 

 13.5(45.2) 

 5.4(18.1) 

 12.5(41.8) 



contour of head. Interorbital space flat, 2.5 (1.9) times eye 

 diameter. Gill opening short, 1.0 (0.9) times eye diameter, 

 at 45° angle, entirely above pectoral-fin base and slightly 

 anterior to it (distance between ventral end of gill opening 

 and base of upper pectoral ray about equal to length of gill 

 opening). Opercular flap small, acute. Opercle very long, 

 directed ventrally and posteriorly, its tip below level of pos- 

 terior end of lower jaw. Interopercle of similar length, vis- 

 ible externally, its anterior tip projecting anteriorly from 

 ventral contour of head (Fig. 1). Long opercle, interopercle 

 and elongated branchiostegal rays support membranes 

 of enlarged branchial cavity that appears externally as 

 a black posterior part of head. Branchial cavity length 

 slightly more than half head length. Branchiostegal rays 

 (4+2) long and distinctly visible externally. Gill rakers 

 modified, closely but irregularly set, mostly alternating 

 (especially on gill arch one), often paired on the outer 

 and inner sides of each gill arch (central part of arches 

 two and three); plates flattened, triangular, similar in 

 shape to those in P. pallidus or Psednos sp.l of Chernova 



and Stein (2002, Figs. 9 and 13). spinule-bearing surface 

 directed internally, flat and longitudinally oval. Spinules 

 closely set, usually in two longitudinal rows, each of five 

 to eight spinules, often with a few additional spinules in 

 between (Fig. 2C). 



Sensory pores difficult to see because of thin transpar- 

 ent skin (damaged in paratype). Nasal pores 2, the poste- 

 rior on a vertical through center of eye. Paired nasal bones 

 (through which the nasal canals run) long, tubular, and 

 visible externally. Coronal pore absent. Lacrimal bones 

 (bearing anterior portion of infraorbital canal) large, vis- 

 ible externally, slightly prominent anteriorly. Infraorbital 

 canal (better preserved in holotype) interrupted behind 

 eye, infraorbital pores 6 (5+1), posteriormost above poste- 

 rior margin of eye (Fig. 2A). In paratype, skin behind eye 

 missing. Preoperculomandibular pores 6 (3 on lower jaw 

 + 3 on preopercular area). Two temporal pores present: t x 

 a short distance behind posterior margin of eye, and t sb , 

 the suprabranchial pore, above and in front of gill opening 

 (Fig. 2A). 



