Description of two new species of Bassozetus (Ophidiiformes: Ophidiidae) and a redescription of Bassozetus robustus Smith and Radcliffe 1913

First Record of the Rare Deepwater Assfish <i>Bassozetus mozambiquensis</i> (Ophidiiformes: Ophidiidae) from the Western South Atlantic

“…30), 63 total vertebrae (vs. 65) and short pelvic-fin, 9.0% SL (vs. 9.5%) (Table 1). The differences in other counts and measurements between the present specimen and B. mozambiquensis (within three and 2.6 points, respectively) are minor, and regarded here as intraspecific variations due to similar ranges existing in other species of Bassozetus (see Nielsen and Merrett 2000;Tomiyama et al 2015Tomiyama et al , 2018Tomiyama et al , 2021. There being no other signifi- (Tomiyama et al 2018(Tomiyama et al , 2021.…”

“…Eye diameter and number of oblique scale (missing during or after collection) rows between the anus and dorsal-fin base followed Nielsen and Merrett (2000) and Tomiyama et al (2018). Preanus, prepelvic, preanal and tail lengths and distance between the pelvic and anal fins followed Tomiyama et al (2015Tomiyama et al ( , 2021, other counts and measurements following Hubbs and Lagler (1958). Vertebral counts were based on radiographs.…”

“…mozambiquensis differs from B. nielseni,(119)(120)(121)(122)(123)(124)(125)(126)respectively), and from B. nielseni, B. squamosus and B. trachibranchus in having 30 or 31 oblique scale rows (vs. 20-25, 44-47 and 39-45, respectively). Sagittal morphology can also be used to distinguish B. mozambiquensis from the above four species, as follows: dorsal margin smooth (vs. one or two indentations present on margin in B. squamosus, B. trachibranchus and specimens of B. robustus over 186 mm SL); a small process absent on anterior margin [vs. present (as a wide bulge) in most specimens of B. nielseni] (Tomiyama et al , 2018(Tomiyama et al , 2021.…”

“…The deep-sea ophidiid genus Bassozetus Gill, 1883 currently comprises 16 valid species, excluding Bassozetus elongatus Smith and Radcliffe in Radcliffe, 1913, which has been synonymized under Bassozetus compressus (Günther, 1878) (Nielsen and Merrett 2000;Tomiyama et al 2015Tomiyama et al , 2018Tomiyama et al , 2021. Species of the genus are mainly benthopelagic, inhabiting depths of ca.…”

“…1000-5500 m in tropical to subarctic waters worldwide, although Bassozetus zenkevitchi Rass, 1955 is usually collected from the water column shallower than ca. 2000 m, an indication of its pelagic life style (Nielsen et al 1999;Nielsen and Merrett 2000;Tomiyama et al 2015Tomiyama et al , 2018Tomiyama et al , 2021.…”