Pseudoscopelus lavenbergi Melo, Walker Jr. & Klepadlo 2007

Melo, Marcelo R. S., 2019, A revision of the genus Pseudoscopelus Lütken (Chiasmodontidae: Acanthomorphata) with descriptions of three new species 2710, Zootaxa 2710 (1), pp. 1-78 : 65-66

Pseudoscopelus lavenbergi Melo, Walker Jr. & Klepadlo 2007

Figures 23 A , 26 B , 27 A–B , 28 N; Table 10.

Pseudoscopelus lavenbergi Melo et al. 2007: 36–41 , figures 4, 5, 6. [type locality: eastern Central Pacific , off Ecuador, 1 o 21’N, 86 o 36’W, holotype SIO 71-358 , 73.0 mm].

Pseudoscopelus savagei Lavenberg 1974: 247–260 , figures 50–51 [Eastern Pacific; name not available in accordance to the ICZN 1999].

Diagnosis. Same as for the species group.

Description. Medium-sized species of Pseudoscopelus , largest specimen examined 181.0 mm SL. Morphometric data summarized in Table 10. General body shape as for species group.

Description. Medium-sized species of Pseudoscopelus , largest specimen examined 70.2 mm SL. Morphometric data summarized in Table 10. General body shape as described for genus with diagnostic characteristics of species and species group.

First dorsal-fin rays viii (11*); second dorsal-fin rays ii+21 (5*), ii+22 (3), ii+23 (3); anal-fin rays iii+20 (4*), iii+21 (4), iii+22 (2), vi+21 (1); pectoral-fin rays 12 (3*), 13 (5), 14 (2), 15 (1); pelvic-fin rays I+5 (11*); caudal-fin rays i+7+8+i (9*), i+8+7+1 (2). Branchiostegal rays 7 (11*). Pre-caudal vertebrae 17 (3), 18 (2*); total vertebrae 37 (2*), 38 (3).

Lateral line complete; lateral-line pores 77 (1), 78 (3*), 80 (4), 81 (3). Pores in temporal canal 2 (11*); supratemporal canal 3 (11*); otic canal 2 (11*); supraorbital canal 6 (11*); supranasal pore 2 (9*), 3 (2); epiphyseal branch 3 (11*); infraorbital canal 12 (11*); preopercular canal 5 (11*); mandibular canal 6 (11*); fifth pore of mandibular canal 1 (3), 2 (3*).

Dentition. Enlarged teeth on premaxilla, dentary and palatine. Teeth arrangement illustrated by Melo et al. (2007). Premaxilla moderately wide, widest point of premaxillary body 15–20 % in premaxillary length.

Premaxillary teeth on head, neck, body and caudal process. Lateral series in single longitudinal row, along lateral edge of premaxillary head, neck, body and caudal process; teeth conical, slightly curved. Canine and fang on ventral shelf of premaxillary head. Middle and mesial series of premaxilla on ventral shelf of body. Middle series in three, irregular, longitudinal rows; teeth needle-like, straight, gradually increasing in size from lateral to medial. Mesial series in transverse rows, each row with three to four teeth; teeth needle-like, slightly curved, gradually increasing in size from medial to mesial.

Dentary teeth in lateral and mesial series. Lateral series along lateral shelf of dentary, in single, longitudinal row, extending from symphysis to posterior tip; teeth conical, slightly curved. Mesial series in transverse rows of one to four teeth; teeth straight, needle-like, gradually increasing in size from lateral to mesial. Palatine teeth 4 (3), 5 (4), 6 (1), 7 (1*), 8 (2); in single, longitudinal row.

Teeth on infrapharyngobranchials and fifth ceratobranchial, conical, curved. Teeth on second basibranchial 9 (1), 10 (1), 11 (1), 13 (1*), 14 (4), 15 (1), 16 (1), 19 (1), conical, in V -shaped or single, irregular row. Teeth absent on basihyal and other basibranchials. Gill rakers on first epibranchial 0 (10*), 2 (1); first ceratobranchial 9 (2*), 12 (4), 15 (1), 18 (2), 19 (1), 23 (1); first hypobranchial 6 (1*), 7 (1), 8 (1), 9 (5), 11 (1), 13 (1), 16 (1). Gill rakers absent on other elements.

Luminescent organs. Luminescent organs present as discrete photophores on head and body ( Fig. 26 B ). Photophores on head: dnf, info 1-2, mxf, opf, pof absent; vnf in small triangular patch of few organs, slightly posterior to first supraorbital pore; apf triangular, short, restricted to angle between premaxilla and preopercle; amf medial to mandibular canal, from halfway between second and third pores, to halfway between third and fourth pores; pmf in two rows, lateral to mandibular canal, from fourth pore to halfway between fifth and sixth pores.

Photophores on body: lvf, rtf, scf, spf and svf absent; pf in single row along ventralmost pectoral-fin ray; paf in triangular patch at pectoral-fin axil; vf in single row, to half halfway of pelvic fin, on mesial ray; vaf short, continuous with vf and trf, extending over base of pelvic rays 4-5; if elongate, in two to four rows of photophores, from isthmus to ventral edge of cleithrum; prvf short, 1/3 of if, in one to four rows; ptvf short, from halfway between anus and pelvic fin, to close to anus, in one to three rows; trf in broad band of three or four rows; saf reaching anus, but not extending further anteriorly, in single row except for anterior part, posterior ends not connected; prcf in posterior half of peduncle, tri-pronged, extending over anterior lower procurrent caudal-fin rays.

Color. Most specimens examined faded to light brown. Body uniformly brown, except for triangular area on epiphyseal branch. Pectoral, pelvic, first and second dorsal fins, and anal fin slightly pigmented; caudal fin pigmented. Internal part of mouth and gill arches entirely black, including skin on toothed area of premaxilla and dentary, over basihyal and basibranchials, roof, floor and lateral wall of mouth, internal part of opercle, membrane between dentaries and premaxillae, and gill arches; gill filaments pale.

Distribution. In the Eastern Pacific, from California to Chile, extending west to near the Hawaiian Islands; from 32 o N to 23 o S, 88 o to 158 o W ( Fig. 23 A ).

Bathymetric distribution. Meso- to bathypelagic; most specimens from 200 to 1638 m (mean 999 m); only a two lots from deeper than 2000 m ( LACM 33340-1 , 2300–3000 m; UW 116439, 0–2100 m) .

Remarks. Prokofiev and Kukuev (2008) fail to include this species in their revision.

Figures

FIGURE 23. Map of distribution of (A) Pseudoscopelus aphos (diamond), P. lavenbergi (cross), and P. parini (circle); (B) P. astronesthidens (cross), P. australis (asterisk), and P. odontoglossum (star). Each symbol may represent more than one locality; solid symbols represent type localities.

FIGURE 26. Schematic drawing of the photophore pattern in lateral and ventral views of (A) Pseudoscopelus odontoglossum, SIO 61-48, mm, holotype. (B) P. lavenbergi, CAS 61407, 63.0 mm, paratype. Dashed lines indicate level of anus.

FIGURE 27. Pseudoscopelus lavenbergi: (A) LACM 30573-1, 86.3 mm, paratype; (B) CAS 61407, 63.0 mm, paratype.