アイザメ科 Centrophoridae Gulper
Sharks
2 トガリヘラツノザメ（新称）
Deania profundorum
(Smith and Radcliffe, 1912) Arrowhead Dogfish
Specimens examined:
2 (
Measurements (all expressed as % TL):
head length 23.8–25.3; head width 10.3; pre-caudal-fin length 81.0–89.7;
pre-first dorsal-fin length 35.9–38.9; pre-second dorsal-fin length 65.9–73.5;
pre-pectoral-fin length 23.2–24.2; pre-pelvic-fin length 61.1–68.7;
pectoral-fin length 10.9–11.8; pectoral-fin base 5.8–6.1; dorsal caudal-fin
margin 17.3–18.3; preventral caudal-fin margin 12.2–13.0;
first dorsal-fin length 20.1–20.6; first dorsal-fin anterior margin10.8–12.2;
first dorsal-fin height 5.6–6.3; second dorsal-fin length 15.8–16.7; second dorsal-fin
height 6.3–7.0; pelvic-fin length 5.4–5.6; pelvic-fin anterior margin 7.5–7.6;
caudal-peduncle height 3.7–3.8; mouth width 6.2–6.5; interorbital
width 7.2–7.8; nostril width 1.9–2.1; internarial
width 3.7–4.0; pre-branchial length 21.2–22.2; pre-spiracular length 15.5–16.7; pre-orbital length 10.4–11.5.
計測形質（全て% TL）：頭長23.8–25.3；頭幅10.3；尾鰭前長81.0–89.7；第1背鰭前長35.9–38.9；第2背鰭前長65.9–73.5；胸鰭前長23.2–24.2；腹鰭前長61.1–68.7；胸鰭長10.9–11.8；胸鰭基底長5.8–6.1；尾鰭上葉長17.3–18.3；尾鰭下葉長12.2–13.0；第1背鰭長20.1–20.6；第1背鰭前縁長10.8–12.2；第1背鰭高5.6–6.3；第2背鰭長15.8–16.7第2背鰭高6.3–7.0；腹鰭長5.4–5.6；腹鰭前縁長7.5–7.6；尾柄高3.7–3.8；口幅6.2–6.5；両眼間隔7.2–7.8；鼻孔幅1.9–2.1；鼻孔間隔3.7–4.0；鰓孔前長21.2–22.2；噴水孔前長15.5–16.7；眼前長10.4–11.5．
特 徴 体は太くて長い．吻はきわめて長く，扁平なヘラ状．吻長は口裂の中央から胸鰭基部までの距離よりも長い．鰓孔は5つでやや大きい．口はやや小さい，歯は両顎とも切歯状；下顎歯は上顎歯より幅広い．背鰭は2基で，それぞれの始部に溝を伴った鋭い棘が1本ある．第1背鰭の棘は，第2背鰭の棘より短い．第1背鰭は比較的，短く低い．臀鰭はない．尾柄は短い．腹鰭・尾鰭間の腹部正中線上に隆起線がある．全身が暗褐色で，各鰭は黒みが強い．
分 布 インド・西太平洋および大西洋．陸棚および島棚斜面の水深275–1785 m（Compagno,
1984; Sousa et al., 2009）．
備 考 計測はCompagno
(1984)にしたがった．本海域には同属他種のヘラツノザメDeania calcea
(Lowe, 1839)が分布するが，本種は尾柄部腹面に隆起線をもつことで，これを欠くヘラツノザメを含む同属他種と容易に識別される．同属他種と比べてやや小型で全長約110
cmに達する．本種の生物学的知見はマデイラ諸島沖の個体群について詳しく報告されている（Sousa
et al., 2009）．
（松沼）
Description
Body thick and elongated. Snout greatly
elongated, flattened, its length greater than distance from mid-point of mouth
to pectoral-fin origin. Five rather large gill openings. Mouth relatively
small. Teeth on both jaws bladelike; teeth on lower jaw broader than those on
upper jaw. Two dorsal fins; both fins with grooved spines; spine of first
dorsal fin shorter than that of second dorsal fin. First dorsal fin relatively
short and low. Anal fin absent. Caudal peduncle short. Ventral portion of
caudal peduncle with subcaudal keel. Body uniformly
dark brown; fins blackish.
Distribution Indo-West
Pacific and
Remarks
Measurements generally followed Compagno (1984). This species can be easily distinguished
from all its congeners that co-occur in the southwestern
(M.
Matsunuma)