Hymenocephalus italicus Giglioli, 1884: 228 Hymenocephalus italicus : Vaillant, 1888: 211 Marshall & Iwamoto, 1973: 605 Cohen et al. , 1990: 230 Bathygadus cavernosus Goode & Bean 1885: 598 Hymenocephalus cavernosus : Goode & Bean, 1896: 408 Macrurus ( Mystaconurus ) cavernosus : Alcock, 1899: 117 Head and otolith morphology of the genera Hymenocephalus, Hymenogadus and Spicomacrurus (Macrouridae), with the description of three new species Schwarzhans, Werner Zootaxa 2014 2014-11-28 3888 1 1 73 3NJ92 Giglioli, 1884 Giglioli 1884 [151,629,1225,1251] Actinopterygii Macrouridae Hymenocephalus Animalia Gadiformes 54 55 Chordata species italicus   Figs. 28A–P, 29      Hymenocephalus italicus  Giglioli, 1884: 228( typelocality: off Genoa, Italy).     Hymenocephalus italicus: Vaillant, 1888: 211;  Marshall & Iwamoto, 1973: 605; Iwamoto in  Cohen et al., 1990: 230.   Bathygadus cavernosus Goode & Bean 1885: 598.     Hymenocephalus cavernosus: Goode & Bean, 1896: 408.     Macrurus( Mystaconurus) cavernosus: Alcock, 1899: 117(Gulf of Mexicoonly).   Material examined. 63 specimens;  12 specimens BMNH1939.5.24.705–716, 04°58’N, 73°16’E;  4 specimens IORAS 00224, 88–135 mmTL, 25°28’S, 35°14’E;  1 specimen IORAS 00225, 171 mmTL, 09°28’S, 60°08’E;  8 specimens IORAS 00226, 104–160 mmTL, 08°47’S, 59°55’E;  2 specimens MCZ43020, 125+ –127+ mm TL, 07°40’N, 54°47’W,  548 m;  7 specimens MCZ43049, 29°08’N, 88°13’W,  457 m;  1 specimen(otolith only) MCZ51404, 23°22’N, 79°56’W,  521–548 m;  3 specimens(otoliths only) MVZ52949, 21°21’N, 17°37’W,  400 m;  1 specimen MCZ57926, 11°36’N, 62°46’W,  530 m;  2 specimens USNM 109502, 123and 152 mmTL, Maldives, Kardivachannel, 5°N, 73°E, John Murray Expedition;  1 specimen ZMB 17646, 165 mm TL, 00°27’N, 42°47’E;  1 specimen ZMB22336, 137+ mm TL, 01°40’N, 41°47’E;  1 specimen ZMB22337, 144+ mm TL, 00°27’N, 42°47’E;  1 specimen ZMB 34033, 166 mm TL, off Mauritania;  1 specimen ZMB 34055, 158 mm TL, off Mauritania;  3 specimens ZMB34063, 125– 146 mmTL, off Mauritania;  3 specimens ZMUC  23.8.1890, journal 52.53.57, 95– 105 mmTL, off Morocco;  2 specimens ZMUC  1.11.1892, 81– 114 mmTL, off Messina, Italy;  8 specimens ZMUC 373411–373418, 74+ – 178 mmTL, 29°55’S, 31°20’E; 1 specimen(otolith only) leg. John Fitch, Mediterranean (no further data).   Diagnosis.Pelvic fin rays 11, rarely 10 or 12; pectoral 12–14; gill rakers 20–25. Barbel short 7–12% HL, not or just reaching vertical through anterior rim of orbit. Orbit 34–38% HL. Snout pointed, protruding, 18–20% HL. Ventral striae extending to about ½ to ⅔ the distance from pelvic fin bases to periproct ( Fig. 28G). Otolith compressed, OL:OH = 0.8–0.95; colliculi fused; pseudocolliculum long, TCL:PCL = 1.5–1.7.  Comparison.  Hymenocephalus italicusresembles  H. heterolepisand  H. puntbut differs from both in having a larger orbit (34–38% HL vs 28–32% HL) and a compressed otolith with fused colliculi (vs. separated colliculi). The latter is also the best character to distinguish it from the otherwise closely similar  H. antraeus, which further differs in having a shorter barbel (3–4% HL vs. 7–12% HL) and the more rounded and less protruding snout.   Description.Head morphology (n = 4) ( Fig. 28A–F): Snout moderately long, pointed, projecting, 18–20% HL, orbit diameter large, 34–38% HL, interorbital width 55–70% HW. Barbel short, 7–12% HL, mostly reaching vertical through anterior rim of orbit. Head canals well developed, infraorbital width 9–14% HL, supraorbital canal with 5–6 segments, width 12–15% HL, supratemporal canal moderately wide, above segment 4 of supraorbital canal, preopercular canal width 12–16% HL, postorbital-preopercular interspace 5–7% HL. Infranasal supporter moderately large; infraorbital supporter short, expanding only beyond rear part of orbit, 30–50% OD; preopercular supporter moderately long, 4–7% HL, with straight rear margin. Otolith morphology (n = 9) ( Fig. 28I–P): Otolith large; OL:OH = 0.8–0.95; OH:OT = 3.5. Dorsal rim with very large and broad, often crenulated predorsal lobe, distally inclining to posterior tip with small incision; posterior tip at about level of sulcus termination; ventral rim deep, regularly curved, mostly smooth, deepest anterior of the middle; anterior rim high, subvertical to nearly vertical. Inner face slightly convex, with median sulcus. Colliculi completely fused, terminating far from anterior and posterior tips of otolith; pseudocolliculum very long. TCL:PCL = 1.5–1.7. Dorsal depression moderately large, indistinct; ventral furrow moderately distinct, close to ventral rim.   Discussion.  Hymenocephalus italicusis one of the more widespread species of the genus and specimens were examined from a variety of geographic origins. Specimens from the western Atlantic ( Fig 28A, D) and Indian Ocean ( Fig. 28C, F) generally seem to have slightly longer barbels than those from the eastern Atlantic ( Fig. 28B, E). Otoliths from specimens from the western Atlantic ( Fig. 28I, N) are generally more compressed and have a smoother outline than those from specimens from the eastern Atlantic ( Fig. 28J, O) or the Indian Ocean ( Fig. 28K–M, P). However, none of these subtle differences appear to be stable enough to warrant distinction at the species or even the subspecies level. Larger statistical series would have to be analyzed or DNA-methods applied for confirmation of any distinction between them.   Distribution( Fig. 29).  Hymenocephalus italicusis common in the tropical western Atlantic, in the eastern Atlantic from Portugalto Angola, the Mediterranean and the western Indian Ocean so far recorded from off southern Somaliato Zanzibar, off Mozambiqueto Durban, along the Mascarene Ridge and off Maldives. Reports from the eastern Indian Ocean (Bay of Bengal and Andaman Sea) represent  H. heterolepisand records from the Gulf of Aden represent  H. punt. [412,605,1329,1351] Italy Genoa 54 55 1 [573,1279,1537,1562] BMNH 4.9666667 1306 73.26667 54 55 12 IORAS -25.466667 1246 35.233334 54 55 IORAS 00224 4 [739,1409,1572,1597] IORAS -9.466666 1299 60.133335 54 55 IORAS 00225 1 IORAS -8.783334 1300 59.916668 54 55 IORAS 00226 8 MCZ 43020 MCZ 548 7.6666665 1303 -54.783333 54 55 125 2 MCZ 43049 [466,1069,1641,1666] MCZ 457 29.133333 1228 -88.21667 54 55 7 MCZ 51404 MCZ 535 23.366667 1256 -79.933334 54 55 1 MVZ 52949 [617,1408,1676,1701] MVZ 400 21.35 1264 -17.616667 54 55 3 MCZ 57926 MCZ 530 11.6 1295 -62.766666 54 55 1 USNM Maldives 5.0 Kardiva 43062 73.0 54 55 USNM 109502, 123 2 ZMB 17646 [768,1410,1745,1770] ZMB Maldives 0.45 1308 42.783333 54 55 1 ZMB 22336 ZMB Maldives 1.6666667 1308 41.783333 54 55 137 1 ZMB 22337 ZMB Maldives 0.45 1308 42.783333 54 55 144 1 ZMB 34033 [265,912,1814,1839] ZMB Mauritania Mauritania 54 55 1 ZMB 34055 ZMB Mauritania Mauritania 54 55 1 ZMB 34063 [291,976,1849,1874] ZMB Mauritania Mauritania 54 55 3 1890-08-23 ZMUC Morocco Morocco 54 55 3 [629,1407,1884,1909] 1892-01-11 ZMUC Italy Messina 54 55 2 ZMUC Italy -29.916666 1224 31.333334 54 55 ZMUC 373411-373418, 74 8