Amutatiola macroventosa, Lu & Okutani, 2022

Lu, Chung Cheng & Okutani, Takashi, 2022, Two new genera and species of sepioline squids (Cephalopoda: Sepiolidae) from Australia, Memoirs of Museum Victoria 81, pp. 1-23 : 8-17

Amutatiola macroventosa n. gen., n. sp.

Figures 6–13 ; Tables 3 , 4

Material examined: Holotype: MOV F80081: south-east Tasmania, 42° 38.1' S, 148° 12.4' E, trawl depth 36–42 m, bottom depth 86–90 m, collected by CSIRO, FRV Soela SO 1/85/124, 27 Feb 1985, 0331 hr, Rectangular Midwater Trawl with 8 m 2 mouth area, 1 male, 9.8 mm mantle length, mature (specimen #1).

Paratype 1: MOV F275293: Great Australian Bight, 32° 43' S, 126° 00' E–32° 45' S, 125° 59' E, 40–170 m, collected by CSIRO, FRV Soela SO 3/80/32, 13 May 1980, 0100 hr, IYGPT, 1 female, 12.2 mm mantle length, mature (specimen #11) .

Paratype 2: WAM 3091-83 : west side of Irwin Reef, Port Denison, Western Australia, 29° 16' S, 114° 55' E; 7–8 m, collected by N. Sinclair, 4 Apr 1983, Rotenone Station , 1 male, 9.5 mm mantle length, mature (specimen #3) .

Paratype 3: MOV F80083: south-east Tasmania, 42° 39.7' S, 148° 12.1' E, trawl depth 5–10 m, bottom depth 90–95 m, collected by CSIRO, FRV Soela SO 1/85/104, 15 Feb 1985, 2034 hr, Rectangular Midwater Trawl with 8 m 2 mouth area, 1 male, 9.6 mm mantle length, mature (specimen #2) .

Paratype 4: MOV F275294: Great Australian Bight, 33° 30' S, 131° 50.0' E–33° 30' S, 131° 53' E, 200– 144 m, collected by FRV Soela SO 3/80/1, 8 May 1980, 1 female, 12.8 mm mantle length, mature (specimen #9) .

Paratype 5: MOV F158244: Luck Bay, western point off beach, Cape Le Grand National Park , Western Australia, 33° 59' S, 122° 13' E, 5 m, active over algae, collected by D. Rawlins, J. Finn and M. Norman, 26 April 1998, 1915 hr, hand net, 1 male, 8.8 mm mantle length, mature (specimen #4) .

Paratype 6: MOV F275296: Luck Bay, western point off beach, Cape Le Grand National Park , Western Australia, 33° 59' S, 122° 13' E, 5 m, active over algae, collected by D. Rawlins, J. Finn and M. Norman, 26 April 1998, 1915 hr, hand net, 1 female, 6.2 mm mantle length, subadult (specimen #17) .

Paratype 7: MOV F275295: Luck Bay, western point off beach, Cape Le Grand National Park , Western Australia, 33° 59' S, 122° 13' E, 5m, active over algae, collect. by D. Rawlins, J. Finn and M. Norman, 26 April 1998, 1915 hr, hand net, 1 male, 8.1 mm mantle length, mature (specimen #5) .

Paratype 8: MOV F91362: Luck Bay, western point off beach, Cape Le Grand National Park , Western Australia, 33° 59' S, 122° 13' E, 5 m, active over algae, collected by D. Rawlins, J. Finn and M. Norman, 26 April 1998, 1915 hr, hand net, 1 male, 6.9 mm mantle length, mature (specimen #7) .

Other material: MOV F80087: Franklin Island , South Australia, 32° 27'S, 133° 40'E, sub-light, 4 Apr 1953, 1 male, 8.0 mm mantle length, mature; 1 female, 9.2 mm mantle length, subadult (specimens #6, 16) .

MOV F80085:GreatAustralian Bight, 32° 43'S, 126° 00'E – 32° 45'S, 125° 59' E, 40–170 m, collected by CSIRO, FRV Soela SO3/80/32, 13 May 1980, 0100 hr, IYGPT , 1 male, 6.6 mm mantle length, subadult; 9 males, 7.7–9.6 mm mantle length, mature; 3 females, 4.7–6.5 mm mantle length, juveniles.

MOV F80086: Great Australian Bight, 33° S, 126° E, 48–50 m, collected by CSIRO, FRV Soela S03/80/33, 13 May 1980, IYGPT , 1 male, 7.1 mm mantle length, subadult; 2 males, 8.5–9.8 mm mantle length, mature; 1 female, 12.2 mm mantle length, mature.

MOV F80084: Great Australian Bight, 33° 22' S, 125° 27' E – 33° 23' S, 125° 27' E, 64 m, collected by CSIRO, FRV Courageous Q 47/51, 7 Apr 1979, 2 females, 10.3–13.2 mm mantle length, mature (specimens #8, 15) .

MOV F77100: Bass Strait , 60 km west of Cape Frankland, Flinders Island, 39° 53' S, 147° 03' E, trawl depth 20–60 m, bottom depth 66–68 m, collected by CSIRO, FRV Soela SO 1/82/1, 16 Jan 1982, 1 female, 5.6 mm mantle length, juvenile; 4 females, 10.6–12.6 mm mantle length, mature (specimens #10, 12, 13, 14; four larger specimens) .

MOV F80082: Great Australian Bight, 33° 30' S, 131° 50.0' E – 33° 30' S, 131° 53' E, 200– 144 m, collected by FRV Soela SO3/80/1, 8 May 1980, 9 males, 4.8–7.6 mm mantle length, immature; 3 females, 5.4–6 mm mantle length, immature.

MOV F80080:GreatAustralian Bight, 32° 22'S, 131°19'E–32°17'S, 131° 18' E, 54–68 m, collected by CSIRO, FRV Soela SO 3/81/41, 6 Aug 1981, 2130 hr, IYGPT, 2 females, 10.4–13.3 mm mantle length, mature .

MOV F158291: Port Victoria Jetty , South Australia, 34° 29' 45” S, 137° 28' 53” E, collected by J. Finn and Mark D. Norman, 21 May 1998, 1 female, 10.9 mm mantle length, mature .

Description: Mantle (figs 6a–c, 7, 8a–b) short dome-shaped with blunt posterior end, slightly longer than wide, muscular, studded by large chromatophores, fused with head dorsally. Anterior ventral mantle margin (figs 6b, 7b, 8b) shallowly concave with blunt lateral projections at position of mantle–funnel connectives, reaching level of posterior margin of eye lens. Head slightly narrower than mantle, head length about 50% of mantle length. Nuchal commissure moderately wide, width 38.6–50.5% of mantle width at commissure in males, 43–59% of mantle width at commissure in females, commissure does not reach beyond medial borders of bulbous eyes.

Head almost entirely occupied by a pair of large bulbous eyes with elliptical eye lid. Cornea membrane protecting eye attached to skin of head along dorsal margin. Olfactory papilla located behind posterior corner of eye orbit, ventral photosensitive vesicle not found. Funnel (figs 6b, d, 7b, d, 8b) long and slender, lacking pigmentation, reaching the level beyond anterior eye margin, and free from head for 55–80% of funnel length. Funnel connects to head by an oblique muscle band extending from beneath anterior end of funnel locking cartilage to ventro-posterior corner of eye.

Dorsal funnel organ (fig. 8e) broad V-shaped with a blunt papilla at the apex. A prominent funnel retractor muscle connected funnel near base with ventro-posterior periphery of eye. Ventral elements of funnel organ (fig. 8e) tear drop-shaped pad, narrower anteriorly. Funnel valve well developed on dorsal roof, tongue shaped, located well behind funnel aperture.

Funnel locking cartilage (fig. 8d) elongated oval with simple, slightly curved depression in middle, mantle locking cartilage long, low ridge.

Fins (figs 6a–c, 7a–b, d, 8a–b) circular in outline, attach to mantle at mid-point of mantle, meeting mantle smoothly posteriorly, anterior border of fins project forward prominently forming a deep cleft with mantle, border not reaching level of mantle margin, posterior borders of fins convex, less pronounced. Length of fin base about 33% of mantle length.

Arms moderately long, rounded aborally, flattened orally, lacking aboral keel and protective membranes. Arm formula inconsistent, in males arm I or II usually longest, arm III or IV usually shortest; in females, arm II or III longest, arm I or IV shortest. Arm suckers biserial with strong sexual dimorphism in sucker sizes and sucker ring dentitions. Web moderately pronounced between arms III and IV. No heteromorphism exists in morphology of right and left arms in males, specifically in the dorsal arms. Webs shallow between all arms except arms IV where no web exists, web D encloses base of tentacles in both sexes.

In males (figs 6f–h, 7, 9), arm I with up to 28 suckers, some suckers in proximal portion of arm enlarged: first to sixth proximal suckers on both dorsal and ventral series enormously enlarged, the third sucker on ventral series the largest, enlarged suckers on ventral series generally larger than dorsal series. Diameter of enlarged suckers exceed arm width. Arm II with up to 32 suckers, of which proximal second to seventh on ventral series slightly enlarged; no enlargement of suckers on dorsal series, suckers gradually reduced in size from proximal to distal end of arm II. Arm III with approximately 27 suckers, first to fourth proximal suckers on ventral series enormously enlarged (1.6 mm in diameter); no enlargement of suckers on dorsal series. Arm IV with approximately 29 normal suckers, no enlargement. Chitinous sucker rings of normal suckers almost at the same level as muscular rim of suckers, sucker ring margin minutely denticulated (figs 10a, c, d). Chitinous sucker rings of enlarged suckers (figs 10b, e, f) extended aborally beyond level of muscular sucker rims, chitinous ring often covered by thin, opaque membrane, sucker ring divided into 2 parts, distal 33–50% of sucker ring long, semicircular shape, proximal portion of sucker ring lower than distal portion, crescent shaped.

Females with more suckers than the corresponding arm in males. Arm I with up to 34 suckers, arm II with up to 45 suckers, arm III with up to 38 suckers and arm IV to 38 suckers. No enlarged sucker in females (figs 8c, 10g –j). Chitinous sucker rings (figs 10i–j) similar to the non-enlarged suckers in males, sucker rings entire, with minutely denticulated margin.

Tentacle weak, longer than arms. Club slightly expanded, curled due to the presence of the dorsal web, small carpal suckers in 4 series, manal and dactyl suckers small, numerous in approximately 6–8 series, carpal and manal suckers much larger than dactylus suckers, in the central part of club, particularly those on dorsal 2 series slightly larger than others, suckers slightly diminish in size towards club margins and distally (fig. 11a). Sucker ring dentition of largest club sucker finely toothed around entire minute circle.

Gills with 16–21 lamellae per demibranch, plus a terminal lamella. A pair of yellowish photophores (figs 6e, 11b), opaque with both ends swollen, dumbbell-shaped or elongated kidney-shaped, on both sides of ink sac.

Upper beak (fig. 11c) rostrum slightly curved with pointed rostral tip; jaw angle obtuse; wing long, shoulder (cutting edge) nearly straight; lateral wall deep; rostrum dark brown to black, hood, shoulder and dorsal part of lateral wall light brown, posterior part of hood, most of lateral wall unpigmented, transparent.

Lower beak (figs 11d, e) wide; rostral tip blunt; jaw edge almost smooth, jaw angle indistinct; blunt tooth on shoulder; no notch in hood; lateral wall without fold or ridge, roughly elongate rhomboidal with lower edge concave, corner faintly produced; rostrum and hood light brown in colour, wings and posterior part of lateral wall transparent. Radula (fig. 11f) 7 series, each row with 7 unicuspid teeth.

Gladius absent.

Spermatophores (fig. 12a) small, 8 spermatophores from 5 individuals approximately 2.6–4.1mm long (spermatophore length index 29.3–42.7), greatest width approximately 0.17– 0.25 mm (spermatophore width index 5.4–7), sperm mass moderately long, sperm reservoir about 0.97–1.5 mm (sperm reservoir index 27.9–43.2), structure simple, no obvious ornamental appearance, cement body approximately 0.39– 0.75 mm long, connects to sperm reservoir by a narrow neck, oral end of cement body elongated funnel-shaped (cement body index 11–22), appearance of ejaculatory apparatus plain, without spiral appearance of the preceding species.

Bursa copulatrix closed type, pouch like ( Bello, 2020; fig. 12b), opening at level of base of left gill, running dorsally, on a mature female (Paratype 1) anterior end width approximately 2 mm with slit-like opening approximately 1.1 mm long, length of pouch approximately 2.3 mm, some spermatangia visible at opening of bursa. Mature and maturing females with large nidamental gland, (nidamental gland index 37.2–56.6).

Alcohol-preserved specimens brown in colour, dorsal mantle surface slightly darker than ventral surface. Dark blackish brown chromatophores scattered over brown-coloured background on both dorsal and ventral surfaces of head and mantle, and along aboral surface of all arms. Surfaces of fins devoid of chromatophores and pigmented spots, except a semicircular patch of brown chromatophores along fin insertion on dorsal side of fin. Skin smooth, lacking sculpture or papillae.

Etymology: Species epithet macroventosa is derived from Greek makros meaning large plus Latin ventosa meaning suction cup or sucker. The name denotes the presence of the greatly enlarged suckers on some arms of mature males.

Distribution: Flinders Island, Bass Strait, and south-eastern Tasmania to South Australia and the Great Australian Bight to Port Denison, Western Australia (fig. 13).

Remarks: Apart from Dextrasepiola taenia n. sp. described earlier in this paper, all known species of the subfamily Sepiolinae have the left dorsal arm of maturing and mature males hectocotylised and sucker stalks of some suckers in the copulatory apparatus of the hetocotylus modified into horn-like, hook-like, papillae or laminae ( Bello, 2020; Naef, 1912a, b; 1923; Nesis, 1982). The present species is unique in having enormously enlarged suckers and lacking a hectocotylised arm bearing highly modified sucker stalks in males. There are some species of Sepiolinae that carry enlarged suckers in hectocotylised arms ( Bello, 2020; Naef, 1923), but none is so pronounced as in this species. The female has normal-sized suckers but more of them. In addition to sucker size, strong sexual dimorphism exists in the dentition of the sucker ring: the dentition of the sucker ring of enlarged suckers in males conspicuously differs from that of the females and the non-enlarged suckers in males.

The structure of the cement body and the sperm mass of the spermatophore of this species is simple in appearance, with no obvious ornamentation, as seen in the preceding species or in Sepietta oweniana (d’Orbigny in Férussac and d’Orbigny, 1841; cf. figs 5a, b, 12a; Øresland and Oxby, 2021, figs 59–61).

As in the preceding species, the ranges of the morphometric indices are wide ( Tables 3–4 ). This is certainly due to the range of the state of specimens prior to and during fixation and preservation. With such a wide range of values, it is of dubious value to use them to delineate a specific index for the species.

Figures

Figure 6. Amutatiola macroventosa n. gen. & n. sp. male, holotype (MOV F80081): a, dorsal view; b, ventral view; c, lateral view; d, inside mantle cavity showing funnel locking cartilages, partial photophores; e, diagram of photophores (p; drawn by T. Okutani); f, arm crown showing arm sucker arrangement; g, diagram of arm crown showing sucker arrangement (drawn by T. Okutani); h, diagram of arm IV showing sucker arrangement (drawn by T. Okutani).

Figure 7. Amutatiola macroventosa n. gen. & n. sp. male, paratype 7 (MOV F275295; grids in background: 1 mm × 1 mm): a, dorsal view; b, ventral view; c, arm crown showing arm sucker arrangement; d, lateral view.

Figure 8. Amutatiola macroventosa n. gen. & n. sp.: a, dorsal view, female, paratype 1 (MOV F275293); b, ventral view, female, paratype 1 (MOV F275293); c, arm crown showing arm sucker arrangement, female, paratype 1 (MOV F275293); d, diagram of funnel locking cartilage, female, paratype 1 (MOV F275293; drawn by T. Okutani); e, diagram of funnel organs, male, paratype 3 (MOV F80083; drawn by T. Okutani).

Figure 9. Amutatiola macroventosa n. gen. & n. sp. male, paratype 5 (MOV F158244). Oral views of arms (grids in background: 1 mm × 1 mm): a, right arm I; b, right arm II; c, right arm III; d, right arm IV; e, left arm I; f, left arm II; g, left arm III; h, left arm IV.

Figure 10. Amutatiola macroventosa n. gen. & n. sp. Sucker ring dentition (grids in background: 1 mm × 1 mm): a, left arm IV of male, paratype 5 (F158244) showing normal (non-enlarged) suckers near arm tip; b, right arm III of male, paratype 5 (F158244) showing sucker ring of enlarged suckers; c, d, normal sucker of left arm II of male, paratype 5 (F158244); e, left arm I of male, paratype 5 (F158244) showing enlarged suckers; f, an enlarged sucker of e showing sucker ring; g, dorsal view of female (F275296) showing non-enlargement of suckers; h, ventral view of female (F275296) showing non-enlargement of suckers; i, arm crown of female (F275296) showing non-enlargement of suckers; j, close-up of a portion of an arm of i showing sucker ring dentition.

Figure 11. Amutatiola macroventosa n.gen. & n.sp. (grids in background: 1 mm × 1 mm): a, right tentacular club, male, paratype 5 (MOV F158244); b, photophores (p), male, paratype 5 (MOV F158244); c, lateral view of upper beak, female, paratype 1 (MOV F275293); d, lateral view of lower beak, female, paratype 1 (MOV F275293); e, top view of lower beak, female, paratype 1 (MOV F275293); f, radula, female, paratype 1 (MOV F275293).

Figure 12. Amutatiola macroventosa n. gen. & n. sp.: a, spermatophore, holotype (MOV F80081) Spermatophore length, 3.55 mm (insets: i, close-up of oral cap; ii, close-up of cement body); b, Bursa copulatrix, paratype 1 (MOV F275293; black scale: 1 mm/division) (lflc: left funnel locking cartilage; lg: left gill); arrow points to the bursa copulatrix entrance.

Figure 13. Distributional map of Dextrasepiola taenia n. gen. & n. sp. (blue) and Amutatiola macroventosa n. gen. & n. sp. (red).