AHLSTROM ET AL.: ARGENTINOIDEI 



Table 42. Characters used in Analysis of Four Argentinoid Groups. 



167 



Character 

 number 



Dervied character state 



Outgroup 



1 Accessory cartilage at posterior tip ceratobr. 5 



2 PU, + U, fused 



3 Light organs present 



4 Frontals fused 



5 Epibr. 4 with one post. art. surface 



6 Larval gut with stomach 



7 Pelvic fins form early and large 



8 Swimbladder absent 



9 Urodermal absent 



10 LL scales extend onto caudal fin 



1 1 Larval gut folded 



12 Extrascapular attached to pterotic 



13 Uncinate process lacking on epibr. 4 



14 Pectoral fin forms early and large 



of a line of small melanophores above and below the notochord 

 tip, a patch of melanophores on the opercle and groups of small 

 melanophores on the upper and lower jaws. Balhylagns anlarcti- 

 cus has 3 lateral gut spots, a large lateral trunk melanophore at 

 the I0lh-I2th myomere, and head and notochord pigment sim- 

 ilar to that of B. euryops. Early larvae of B. pacificus have a 

 large lateral blotch at mid-body and another one posteriad on 

 the body. Initially these melanophores are located at the junction 

 of the gut and body but in later larvae are located on the trunk. 

 Later a 3rd blotch forms midway between these two. A 4th 

 lateral trunk blotch forms in some late larval specimens between 

 the pectoral fin and the large mid-body blotch and melanophores 

 form lateral to the liver and at the free terminal section of the 

 gut. Head and notochord pigment is similar to B. euryops and 

 B. antarcticus. 



Bathylagiis hericoides is unusual in having only a series of as 

 many as 18 lateral gut melanophores (Fig. 86). Late postflexion 

 larvae develop pigment on the lower jaw, isthmus, opercle, pec- 

 toral fin base and lateral caudal peduncle. Bathylagus longiros- 

 tris develops a heavier pattern of pigmentation, beginning with 

 a series of small melanophores on the posterior section of the 

 gut in early larvae. Also in preflexion larvae a series of rect- 

 angular-shaped melanophores develops on the hypaxial myo- 

 meres. Later in the larval period the lateral gut series is extended 

 forward along the entire gut, although with wider spacing than 

 on the posterior gut section. Also, the epaxial myomeres develop 

 rectangular-shaped melanophores, beginning posteriorly and ac- 

 cruing anteriorly. The head develops pigmentation from the 

 opercle to the jaws (Fig. 86). Bathylagus ochotensis develops a 

 similar pigment pattern except that the melanophores on the 

 posterior gut section are comparatively larger and fewer, the 

 anterior region of the gut lacks melanophores and the epaxial 

 myomere series is limited to the posterior region. 



Larvae of B. wesethi. B. nigrigenys and B. argyrogaster have 

 a similar pigment pattern that differs markedly from that of 

 other Bathylagus (Fig. 86). Initially there is a series of paired 



melanophores dorsolateral to the gut, extending from the pec- 

 toral fin base to the terminal section. These remain throughout 

 the larval period but become embedded and obscured in late 

 larvae. Bathylagus nigrigenys begins with about 8 pairs, which 

 increase to 10, whereas B. wesethi begins with 6 pairs and has 

 7-8 during most of the larval period. Both species develop pig- 

 ment at the notochord tip; B. wesethi has a dorsal and ventral 

 spot, while B. nigrigenys has only a ventral spot. At notochord 

 flexion a series of melanophores appears along the hypaxial 

 region of the body and, soon after, a series develops along the 

 epaxial myomeres. More lateral series are added and in late 

 larvae the entire body is covered. Melanophores also form in 

 the median finfold of advanced larvae. Initially head pigmen- 

 tation consists of melanophores on the opercle and jaws but in 

 later larvae the entire head is covered. 



Opisthoproctid larvae have distinctive and, in some genera, 

 heavy pigment patterns (Fig. 87). Bathylychnops has a dorsal 

 series of 6 large paired blotches that permeate the musculature, 

 bridge across the longitudinal septum and expand onto the fin- 

 fold. A series of 8 large ventrolateral blotches alternate with 

 those of the dorsal series, with the exception that the postanal 

 blotch lies opposite the dorsal blotch and expands to form a 

 band. A large blotch covers the base of the caudal fin. The head 

 IS heavily pigmented with superficial melanophores on the bran- 

 chiostegals, urohyal and lateral brain and deeply embedded me- 

 lanophores in the snout, jaws, cheek and ventral brain region. 

 The lower limbs of the gill arches and their filaments are heavily 

 pigmented as are both the pectoral and pelvic fin bases. 



The species of Dolichopteryx have lateral series of melano- 

 phores above the gut and some species develop serial melano- 

 phores on the hypaxial myomeres (Fig. 87). Head pigment con- 

 sists of melanophores on the jaws, gill arches and, in most species, 

 the internal snout region. Macropmna develops a series of slant- 

 ed melanophores, one on each hypaxial myomere, and a heavy 

 embedded blotch at the pelvic fin base, that expands both dorsad 

 and ventrad as a band. The caudal fin base has a large blotch 



Fig. 87. Larvae of Opisthoproctidae. (A) Bathylychnops exilis. 1 5.6 mm. CalCOFI 7203 Sta. 67.80; (B) Ventral view of above; (C) Dolichopteryx 

 hinoculans. 58.0 mm, redrawn from Roule and Angel (1930); (D) Afacropinna microstoma. 1 1.7 mm, CalCOFI 7412 Sta. 120.50; (E) Ventral 

 view of above; (F) Rhynchohyalus natalensis. 23.0 mm, from Bertelsen et al. (1965); (G) Opisthoproctus grimaldii. 14.0 mm from Schmidt (1918). 



