Iridoteuthis lophia, Reid, 2021

Reid, Amanda L., 2021, Two new species of Iridoteuthis (Cephalopoda: Sepiolidae: Heteroteuthinae) from the southwest Pacific, with a redescription of Stoloteuthis maoria (Dell, 1959), Zootaxa 5005 (4), pp. 503-537 : 505-512

Iridoteuthis lophia new species

( Figures 1–4 , 11 ; Table 2, 4; Appendices 1, 2) https://zoobank.org/ urn:lsid:zoobank.org:pub:A06EDB00-575C-4F6A-B47F-A9CFB4CF50B4

Type material. Holotype. New Zealand: ♂ (17.5 mm ML), W of New Plymouth , 39°2.27´S, 172°13.50´E, 530– 732 m, RV ‘ James Cook’, Stn J 07/59/80, 12 Apr. 1980 ( NMNZ M.329176) . Paratypes. New Zealand, ♂ (22 mm ML), 2♀ (24.6, 35 mm ML), SW of Cape Maria van Diemen , 34°55.5´S, 172°16.6´E, 428 m, coll. RV ‘ James Cook’, Stn J 05/22/80, 12 Mar.1980 ( NMNZ M.67238) ; ♂ (15.3 mm ML), E of Poor Knights Island , 35°17´S, 175°1´E, 432–479 m, coll. R.D. Cooper, FV ‘ Valkyrie’, 10 Jan. 1969 ( NMNZ M.74102) ; ♂ (14.2 mm ML), W of New Plymouth , 39°2.27´S, 172°13.50´E, 530–732 m, RV ‘ James Cook’, Stn J 07/59/80, 12 Apr. 1980 ( NMNZ M.330459) ; ♂ (10.9 mm ML), ♀ (9.0 mm ML), SW of Cape Foulwind , 42°19.68´S, 170°29.75´E, 153– 143 m over 427– 367 m, RV ‘ James Cook’, Stn J 19/02/78, 9 Dec.1978 ( NMNZ M.67246) ; 2♂ (7.2, 10.6 mm ML), SW of Cape Foulwind , 42°19.68´S, 170°29.75´E, 153– 143 m over 427– 367 m, RV ‘ James Cook’, Stn J 19/02/78, 9 Dec.1978 ( NMNZ M.67887) ; 3♂ (9.5–14.8 mm ML), ♀ (8.5 mm ML), off Hokitika , 42°34.05´S, 170°16.73´E, 204 m over 340–360 m, RV ‘ James Cook’, Stn J 19/08/78, 10 Dec.1978 ( NMNZ M.67885) ; 8♂ (9.5–14.3 mm ML), off Hoki- tika, 42°34.33´S, 170°12.92´E, 285 m over 351– 347 m, RV ‘ James Cook’, Stn J 19/07/78, 10 Dec. 1978 ( NMNZ M.67879) ; ♀, South Island , west coast, RV ‘ W. J. Scott’ (no other data) ( NMNZ M.329174) .

Diagnosis. Funnel in both sexes with dorsal ‘cap’ at distal tip. Arms 1 of males with spade-like distal tip; arms 2 with comb-like arrangement of elongate, fused sucker pedicels with suckers at distal tips; arms 3 swollen, recurved orally, some sucker pedicels elongate, finger-like, some pedicels enlarged, triangular. Distal tips of arms 4 of males with tightly packed tetraserial suckers. Arms 1–3 in males swollen, muscular. Female arms not modified.

Description. Counts and indices for a subset of individual specimens are given in Appendices 1 and 2. Measurements and counts refer to three mature males and two mature females. (Few specimens were measured as most were immature and/or in a poor state of preservation.)

Species relatively large: ML males examined 14.2– 15.7 – 17.5 mm (SD, 1.7); females 19.6– 22.1 – 24.6 mm (SD, 3.5). Mantle short, deep, dome-shaped dorsally and ventrally, head and arms dominate the animal ( Figure 1a ); MWI males 96.6– 105.8 –116.2 (SD, 9.9), female 67.9. Dorsal mantle joined to head by wide occipital band, band extends dorsally from midpoint of each eye; ventral mantle margin wide m-shaped ( Figure 1b ), extends anteriorly beyond head to level with base of arms. Fins oval; length approximately equal to mantle length. FIIa males 13.1– 13.9 –14.4 (SD, 0.6); females 16.3– 21.4 –26.5 (SD, 7.3). Fins wide, FWI males 76.0– 88.5 –101.4 (SD, 12.7); females 50.8– 56.0 –61.2 (SD, 7.4), attached dorso-laterally along mantle. Fins with distinct lobes anteriorly, project anteriorly as far mantle/head junction ( Figure 1a ); posterior lobes of fins extend slightly beyond mantle margin, angled, bluntpointed ( Figure 1b ).

Funnel conical, broad basally, tapers markedly anteriorly in line with anterior margin of eye and where it projects beyond mantle margin beyond base of arms ( Figure 1b ); distal, protruding end of funnel pigmented ventrally and laterally and terminates dorsally in a broad distal cap ( Figure 1c ); dorsal side of funnel with swollen, muscular ridge ( Figure 1d ) that extends anteriorly from junction with head and terminates in a blunt tip posterior to funnel opening (possibly a second bifid opening). FuLI males 80.0– 98.9 –111.1 (SD, 16.6), females 66.3– 67.7 –69.1 (SD, 2.0); free for most of its length, FFuI males 80.0– 90.0 –98.6 (SD, 9.4); females 56.1– 58.5 –61.0 (SD, 3.4). Funnellocking cartilage ( Figure 1e ) long, narrow, slightly curved, broader anteriorly, with groove deepest anteriorly, rim narrow, thin. Mantle cartilage lobe shaped, angled anteriorly to correspond with funnel cartilage ( Figure 1f ). Funnel organ ( Figure 1g ) dorsal element broad, inverted V-shape, with pointed tip anteriorly; ventral elements elongate with acute anterior tips. Funnel valve a small v-shaped flap.

Head deep, broad, HLI males 60.6– 65.2 –73.2 (SD, 6.9); females 62.2– 66.8 –66.8 (SD, 6.5). HWI males 77.1– 87.7 –97.2 (SD, 10.1); female 76.0. Eyes large, bulbous take up most of the sides of the head; pupil also large, eye covered by transparent membrane. EDI males 80.6– 83.9 –89.4 (SD, 4.8); females 45.9– 50.0 –54.1 (SD, 5.8); eyelids free.

Visceral photophore ventral to, and associated with, ink sac; distinct, round, bulbous, iridescent purple in preserved specimens, surrounded by broad pale margin; with prominent paired photophore tubes on each side at intersection of purple bulbous region and paler, muscular ring ( Figure 1h ). Anal opening protrudes slightly beyond photophore. Anal flaps present, very short, pointed ( Figure 1h ).

Arms 1, 2 and 4 similar in length in both sexes, with arms relatively longer in males than females ( Table 2). Arms 3 in both sexes longer than remaining arms, relatively longer in males: ALI 3 in males 108.6– 116.7 –130.3 (SD, 11.9); females 73.2– 80.0 –86.6 (SD, 9.6). Arm morphology distinctive:

Male arms. All arms united by a deep web. Web joining fourth pair of arms very thin, joined to funnel.

Arms 1 with four transverse rows small biserial suckers basally, distal to these, suckers gradually enlarged in dorsal series, with largest suckers towards distal tip of arm (approximately 5–6 large suckers) ( Figure 2a ). Distal- most sucker tiny. Distal end of arm with spade-shaped flap extending between the two sucker series to surround the distal tip of the arm ( Figure 2a, b ).

Arms 2 with ten small suckers (5 transverse rows of biserial suckers) basally, followed by three transverse rows of enlarged suckers. Suckers in ventral series larger than in dorsal series. Distal to these, two to three tiny suckers, then dorsal and ventral sucker pedicels elongate and aligned in a single comb-like row of about 16 elongate pedicels, each with a single tiny sucker; elongate pedicles joined by a thin weblike membrane that extends almost to the tip of each pedicel ( Figure 2c ). At the distal tip of the arm the pedicels are fused completely to form a fleshy flap. Aboral keel in this region wide, well developed ( Figure 2c ).

Arms 3 swollen, very muscular aborally, curved inwards in preserved specimens. (Arms 1 and 2 also broad, robust basally, and curved inwards but not to the extent seen in arms 3.)

Arms with suckers basally in two series, suckers becoming smaller toward middle of arm, protective membrane not crenulated to form lappets. Distal to 9 th tiny sucker, next four sucker pedicels elongate, finger-like in ventral row with medial two pedicels longest, flanked on either side by two shorter pedicels each with a tiny sucker on distal tips ( Figure 2d ). Median two modified pedicels much broader and more elongate on dorsal side of arm ( Figure 2e ), triangular in outline and joined to adjacent pedicels on basal half, two flanking elongate pedicels narrower than middle two, but longer than those on ventral side of arm; proximal pedicel with tiny sucker at tip, distal pedicel without sucker. Protective membranes appear absent on ventral side in modified region, but present as a narrow flap on dorsal side of arm. On distal end of modified region, dorsal and ventral modified rows fuse and are joined together by single elongate pedicel (although shorter than other elongate pedicels) with tiny sucker at its tip and tiny suckered pedicel at its base. Distal third of arms 3 devoid of suckers, with broad, fleshy, dorsal and ventral margins, appears paddle-shaped in outline with rounded distal tip ( Figure 2d ). Dorsal side of ‘paddle’ appears to be a continuation of the arm protective membrane.

Arms 4 with ovoid glandular pad on aboral side of arm approximately midway along arm length. Distinct protective membranes with crenulated lappets. Suckers on proximal two thirds of arm all similar in size, small, in biserial rows, distal tip of arm with markedly reduced and crowded suckers, rows tetraserial.

The elaborate modification of the arms seen in males are discernible in very small immature specimens, ~ 7 mm ML.

Female arms. Arms 1 suckers biserial, very small, arms very narrow distally. Aboral keel not well developed.

Arms 2 similar to arms 1.

Arms 3 suckers small, clearly biserial basally, arm narrowing distally, flattened dorso-ventrally. Protective membrane very narrow. Distal third (approximately) of arms with very tiny suckers, flattening of arms makes suckers appear as if in a single series. Aboral keel well developed, a continuation of membrane joining arms 3 and 2.

Arms 4 with small biserial suckers becoming very tiny towards distal tip of arm. Arms very narrow distally with broad ventral keel that is a continuation of the membrane joining the ventral pair of arms.

Arms of both sexes. Arms 3 with fewer suckers than remaining arms in both sexes (with fewer suckers in males than females) ( Table 2). Arms 4 with greater number of suckers than remaining arms, with males having a greater number of suckers on the ventral arm pair than other arms (110–116 suckers in arms 4 of males, with 10–26 suckers on individual arms 1–3).

Chitinous arm sucker rings: male arms 1 and 2 with smooth rings ( Figures 2g, h ; 3a ); arms 3 and 4 of males ( Figure 3b, d ) and all arms of females ( Figure 2i , 3c, e ) infundibulum with 4–5 rows of pavement-like processes, peripheral sucker rim processes smallest, wedge-shaped or rectangular, rest irregular, roughly hexagonal. Chitinous inner ring of normal arm suckers without teeth. Pavement-like processes very finely pitted distally ( Figure 3b, e ).

Tentacles slender, stalks naked, semicircular in cross section. Club cylindrical with 7–10 suckers in transverse rows; ClLI males 35.9– 39.4 –42.3 (SD, 3.2); female 32.5, recurved distally in preserved specimens, tapers to blunt tip; sucker-bearing face convex. Suckers ~0.4–~ 1.3 mm diameter. Aboral keel absent. Tentacle organ extending along entire length of club and terminates posterior to sucker-bearing face ( Figure 3f ). Club sucker dentition ( Figure 3g, h ): inner ring broad, without teeth, but bears blunt pegs ( Figure 3h ); infundibulum with three rows of pavement-like processes, inner two rings roughly pentagonal in shape outer row small, rectangular; pegs with strongly crenulated and pitted surfaces; processes uniform width from base to distal margins.

Gills with 21–23 lamellae per demibranch. Buccal membrane with six lappets; suckers absent.

Upper beak ( Figure 4a ) with pointed rostrum, hood curved, high above crest posteriorly; jaw angle approximately 90 degrees; lateral wall edge with slight indentation. Lower beak ( Figure 4b ) with blunt protruding rostrum, rostral edge obtuse, curved, without distinct inner angle; hood notch absent, wings almost straight. Distinct dark pigmentation restricted to rostrum and hood of upper and lower beaks.

Radula with seven transverse series of teeth ( Figure 4c ). Rhachidian simple, without cusps, triangular, slim, concave laterally and ventrally. First lateral teeth similar in size and shape to rhachidian, with pointed cusps displaced laterally and directed towards midline of radula. Second and third laterals with elongate bases, longer, curved, slender. Third laterals scythe-like, longer than second laterals.

Gladius absent.

Fully developed spermatophores approximately 1/2 to 1/3 mantle length. Apart from oral end of ejaculatory apparatus with 3–4 simple coils ( Figure 4e ; coils partially unravelled), all spermatophores examined unusually devoid of internal structure, sperm reservoir appears to be continuous along entire length, without distinct cement body. Male reproductive tract similar in structure to congeners ( Figure 4d ).

Female reproductive tract: Ovary occupies large proportion of posterior end of mantle cavity. Nidamental glands paired, broad, located ventral to ovary, almost completely covering ovary. Large, cream-coloured accessory nidamental glands located toward distal end of nidamental glands. Large sac-like bursa copulatrix on animals’ left side. EgDI 9.3– 9.8 –10.2 (SD, 0.6).

Colour. Alcohol preserved specimens cream to maroon with evenly scattered small purple chromatophores on dorsal and ventral head, arms and mantle; animal darker on ventral surface ( Figure 1a, b ). Bulbous area surrounding eye, broad shiny. Fins unpigmented. Funnel pigmented on ventral side of distal tip.

Type locality. New Zealand: W of New Plymouth , 39°2.27´S, 172°13.50´E .

Distribution. New Zealand, SW of Cape Maria van Diemen, 34°55.5´S, 172°16.6´E to 39°2.27´S, 172°13.50´E. All specimens collected in midwater offshore. Depth range (trawl range) 143– 732 m. Bottom depths (where recorded) range between 340– 732 m.

Etymology. The species name lophia is a Greek term meaning ‘mane, crest or comb’ and refers to the distinctive comb-like arrangement of the sucker pedicels in this species. Gender feminine.

Comments. The depth range given reflects the minimum and maximum trawl depths at which the species was collected. Specimens may have been collected at either end of this range or anywhere between.

Measurement data for this species should be treated with caution, as many specimens, particularly the females were laterally flattened, perhaps indicative of freezing prior to preservation, making measurements difficult (and not attempted for most specimens).

The elaborate morphology of the male arms can be used to readily distinguish this species. These modifications are discernible to some degree in the smallest males examined (7.2 mm ML) and may ultimately justify separate generic recognition for this taxon as was the case for Amphorateuthis alveatus Young et al. (2007b) . However, until a comprehensive review of the Heteroteuthinae is undertaken, a conservative approach is taken here, placing lophia in Iridoteuthis to which it conforms in most other respects.

The apparent lack of spermatophore ultrastructure in this taxon is perplexing. The spermatophores of both mature male specimens were examined and both exhibited very simple and uniform internal structure. It is difficult to know whether this has something to do with the nature of preservation or some other cause, but spermatophore ultrastructure should be examined if new material become available.

Differences between I. lophia and other members of the genus are shown in Table 4.

Figures

FIGURE 1. Iridoteuthis lophia, n. sp. a, lateral view, male holotype, NMNZ M.329176, 17.5 mm ML. b, ventral view (specimen as in a) (note the ventral mantle folded posteriorly in this specimen is a preservation artefact). Male paratype, NMNZ M.330459, 14.2 mm ML: c, funnel opening, ventro-anterior view, arrow indicates terminal flap. d, distal end of funnel, lateral view, arrow indicates swollen portion. e, funnel-locking cartilage. f, mantle-locking cartilage. g, funnel organ ventral view. h, visceral photophore ventral view, (pt) photophore tubes, anal opening (ao). Scale bars: a, b = 5 mm; c–f = 1 mm; g, h = 2 mm.

FIGURE 2. Iridoteuthis lophia, n. sp. a, right arm 1, distal tip, ventral view, male paratype, NMNZ M.330459, 14.2 mm ML. b, right arm 1, distal tip dorsal view, male holotype, NMNZ M.329176, 17.5 mm ML. c, right arm 2, distal tip ventral view (specimen as in a). d, right arm 3 ventral view (specimen as in a). e, right arm 3, dorsal view enlargement (specimen as in a). f, arm 3, distal tip dorso-lateral view (specimen as in b). g, SEM, left arm 1 sucker (specimen as in a). h, SEM, right arm 1 sucker (specimen as in a). i, SEM, arm 1 sucker, female, NMNZ M.67238, 24.6 mm ML. Scale bars: a, b, c = 1 mm; d, f = 2 mm; e = 0.5 mm; g, h = 100 µm; i = 20 µm.

FIGURE 3. Iridoteuthis lophia, n. sp. a, SEM sucker, arm 2, male paratype, NMNZ M.330459, 14.2 mm ML. b, SEM, portion of sucker rim arm 3 (specimen as in a). c, SEM, sucker rim arm 3, female paratype, NMNZ M.67238, 24.6 mm ML. d, SEM, sucker rim arm 4 (specimen as in a). e, SEM, sucker rim arm 4 (specimen as in c). f, tentacular club (specimen as in a), arrow indicates tentacle organ. g, SEM, portion of tentacular club (specimen as in a). h, club sucker rim (specimen as in a). Scale bars: a = 100 µm; b, e, h = 10 µm; c, d = 20 µm; f = 1 mm; g = 50 µm.

FIGURE 4. Iridoteuthis lophia, n. sp. a, upper beak, lateral view, NMNZ M.330459, 14.4 mm ML. b, lower beak, lateral view (specimen as in a). c, SEM, radula, male paratype, NMNZ M.330459, 14.2 mm ML. d, reproductive tract (specimen as in c), anterior accessory gland (aag), accessory gland (ag), ciliated canal (cc), distal deferent canal (ddc), genital opening (go), mucilaginous gland (mg), spermatophoric gland (sg), spermatophore storage sac (sss), testis (t). Scale bars: a, b, 1 mm; c = 100 µm; d = 1 mm.

FIGURE 11. Distribution of Iridoteuthis merlini, n. sp. (solid circles); I. lophia, n. sp. (crosses) and S. maoria (open circles) examined in this study. Black arrow indicates the type locality for I. merlini, n. sp. and I. lophia, n. sp.