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Description
Proportional measurements in thousandths of total length, type and paratypes (in brackets). Standard length 991 (986–991); head 147 (138–151); snout 37 (37–39); eye 25 (22–26); interorbital 24 (24–31); cleft of mouth 55 (52–58); postorbital 82 (84–88); branchial aperture 24 (18–24); branchial interspace 50 (39–52); pectoral 41 (39–46); snout-vent 406 (386–410); preanal 432 (409–432); predorsal 150 (142–151); depth at anal origin 79 (61–95); pectoral rays 15 (14–15); anal rays 213 (204–222); dorsal rays before level of vent 75 (65–82); dorsal rays 310 (306–314); caudal rays 8 (8); lateral line pores before level of vent 44 (39–44); lateral line pores 156 (151–170).
Body elongate, robust, compressed significantly only along caudal region, depth greatest at belly, especially in larger specimens, 1.6 in head, tapering evenly behind vent to tip of caudal region. Head prominent, with large eye, moderate gape, fleshy lower lip and well–marked sensory pores and papillae; fins well-developed with clearly-visible fin-rays; lateral line conspicuous, with the pores on the ends of short tubes; hair-like epidermal processes present over surface of body, usually villiform, but divided at their tips in larger specimens.
Head clearly differentiated from trunk, its length contained 1.8 times in trunk or 6.8 in total length; snout fleshy, relatively broader in larger specimens, 4.0 in head, projecting only moderately in advance of lower jaw, with a small longitudinal ridge on its ventral surface immediately anterior to premaxillary teeth; jaws strong, mouth subterminal; gape slightly oblique, falling close to the vertical from middle of pupil, or about 2.7 in head; upper lip scarcely developed, separated from the maxillary teeth by a minutely fimbriated, flat ridge; lower lip thick, fleshy, rounded, almost as in Conger, its inner surface fimbriated; tongue distinct.
Teeth present on maxilla, premaxillo-ethmovomer and dentary. Teeth on maxilla and dentary generally short, all of about the same size, acutely conical, very slightly recurved, closely-packed in irregular rows so as to form a cardiform band on each element. Maxillary band broad anteriorly with six rows of teeth, tapering gradually to two or three rows posteriorly. Premaxillo-ethmovomerine band with less closely-packed teeth and in two portions; anterior, premaxillary portion broadly (transversely) oval, adpressed between tips of maxillae and projecting in front of mandibles for a variable amount in different specimens, but usually for just over half its longitudinal diameter, bearing numerous sharp, retrorse teeth which are larger than those on either the upper or lower jaws; posterior, vomerine portion broad anteriorly and confluent with premaxillary portion, tapering posteriorly to a point level with anterior margin of posterior nostril, twice the length of premaxillary portion or just less than half the length of maxillary band; vomerine teeth broadly conical, more or less irregularly disposed but in about five to six longitudinal rows. Teeth on dentary forming a cardiform band nearly joining with the band of the other side across the symphysis, of about seven rows of teeth anteriorly, tapering sharply posteriorly, but otherwise similar in shape to the maxillary band, although a little shorter.
Anterior and posterior nostrils of the one side separated by a little more than diameter of eye; anterior nostril on anteroventral tip of snout as a short, thin-walled, anteroventrally– directed tube with a complete rim, the medial wall of the tube entirely free from snout; posterior nostril without an external tube, half diameter of pupil in advance of eye, on its horizontal diameter, sometimes with the opening compressed, usually with the opening wide, almost triangular in shape and the rim raised, but not fimbriated. Eye large, oval, with horizontal diameter 1.5 in snout or 3.5 in postorbital; interorbital space flat, relatively wider in larger specimens as a consequence of the broader snout, but about equal to diameter of eye in most specimens. Branchiostegals not obvious through skin but I have counted 10 on each side in two specimens macerated. Branchial aperture lateral, semi-circular, about equal to diameter of eye; dorsal extremity always below middle of pectoral base, often in line with its ventral margin; ventral extremity of aperture tending to be posterior to pectoral base so that aperture is oblique.
Median fins fleshy, with clearly-visible fin-rays, and continuous with the caudal. Dorsal originating variably, more often slightly behind level of pectoral origin, sometimes just in advance of pectoral origin, higher than anal, at vent contained five times in depth of body at that point, but higher near end of caudal region; dorsal fin-rays before level of vent about 75, total rays about 310; anal fin rather less strongly developed, with about 213 rays; caudal
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Text fig. 1.—Pseudoxenomystax hirsutus n.sp. Type, 949 mm t.l. Fig. A—Laterial view. Fig. B—Dorsal view. Fig. C—Lateral view of head. Fig. D—Dorsal view of head. Fig. E—Epidermal processes in the type (upper) and in a specimen of 1028 mm t.l. (lower) from above lateral line near level of vent. Fig. F—Upper (left) and lower (right) dentition, from impressions. Fig. G—Lateral view of neurocranium. Fig. H—Dorsal view of neurocranium. Fig. I—Lateral view of left preorbital bone. Fig. J—Lateral view of caudal skeleton.
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indistinct, with eight rays. Pectoral fin elongate-oval, fleshy, contained exactly twice in postorbital, with 15 rays.
Lateral line marked by a low ridge originating at level of dorsal margin of eye halfway along postorbital, descending gradually to meet midlateral level just posterior to level of vent. Pores numbering about 156 of which the anterior 39–44 lie before level of vent, carried on the ends of short tubes which originate on the lower border of the lateral line ridge and are directed ventrolaterally. Cephalic pores distributed as follows: one large occipital pore lies in the mid-dorsal line at the level of the origin of the lateral line proper; two pairs of small, round pores lie between the anterior nostrils; one small pore behind the anterior nostril; two large, slit-like openings of the rostral canal immediately dorsal to, and between, anterior nostrils; three slit-like pores along the maxilla and one posterior to mouth; nine pores lying linearly along lower jaw and on to opercular region.
Minute, fleshy papillae, indicating the openings of mucous glands, present in rows on the head, a single row between the base of the dorsal fin and the lateral line and in the raised ridge of the lateral line itself. On the snout the papillae make up a pattern of rows in the interorbital space and beneath the eye. On the postorbital region a transverse row lies across the occiput; others lie behind the angle of the mouth and in a semicircular row just in advance of the pectoral. Between the dorsal fin and the lateral line lies a row of widely spaced papillae continuing along the full length of the body. Larger, more obvious papillae occur regularly in the lateral line, one papilla posterodorsal to each lateral line pore. Snout and anterior portion of lower jaw covered with numerous, minute, rounded knobs.
Body surface thickly and almost completely covered with minute, hair-like, fleshy epidermal processes, villiform and little pigmented in smaller specimens, divided at their tips, glove-like, and darkly pigmented in larger examples, so as to give the appearance of a dark, hairy coating to the body.
Colour in life blue-grey above, creamy-white below; dorsal fin dark-edged for a variable amount, anal fin rather less so; snout and nape tinged with violet; pectoral pink (blood vessels), iris iridescent golden. In formalin the colour on the trunk and caudal region fades to brownish-pink.
Pseudoxenomystax bulbiceps (Whitley, 1948).
Bassanago bulbiceps Whitley, 1948. Rec. Aust. Mus. 22 (1): 71.
Ariosoma longicauda Moreland, 1957. In Knox, G. A., Bull. N.Z. Dep. sci. industr. Res., 122: 34.