Adeonellopsis parvirostrum, Hirose, 2016

Hirose, Masato, 2016, Diversity and distribution of adeonid bryozoans (Cheilostomata: Adeonidae) in Japanese waters, European Journal of Taxonomy 203 (203), pp. 1-41 : 23-26

Adeonellopsis parvirostrum sp. nov.

urn:lsid:zoobank.org:act:E46E9CD1-84F7-41DC-9AE9-9164B5262E5E

Figs 10B , 14–15

Adeona n. sp. – Hirose 2010: 50, pl. 86, figs A̅D.

Diagnosis

Colony dichotomously branching; branches flat, roughly 3–4 mm wide. Autozooids oval, distinct, delineated by a deep groove; with a single row of marginal pores. Frontal shield smooth or slightly granulated. Peristome deep, oval. Spiramen monoporous. Two to six tiny pores in frontal wall proximal to orifice. Suboral avicularia triangular, small, almost same size as spiramen; in center of frontal shield, distal to spiramen, directed distally. Triangular marginal vicarious avicularia present. Gonozooids slightly broader than autozooids; orifice broad, proximodistally compressed, with slightly convex proximal margin; spiramen and avicularia almost same size as in autozooids.

Etymology

The specific name derives from the Latin parvus (small) and rostrum (used as a noun in apposition), referring to the small rostrum of the suboral avicularia.

Material examined

Holotype

JAPAN: two branches of single colony collected by NSMT, north-northwest of Hachijo-jima Island , 33°20'54.48" N, 139°41'11.16" E to 33°21'4.32" N, 139°40'30.84" E, 185–213 m depth, with CB dredge from R / V Tansei-maru, 26 Nov. 2007 (NSMT-TeS25).

Paratypes

JAPAN: branch of colony collected by NSMT, same collection data as for holotype (NSMT-TeS27); four dried colony fragments collected by NSMT, NE off Hachijo-jima Island, 33°34'6.00" N, 140°15'54.00" E to 33°34'24.00" N, 140°16'0.00" E, 179–182 m depth, from R / V Shinyo-maru, 23 Oct. 2003 (NSMT- TeS26); small branches of colony collected by NSMT, N of Hachijo-jima Island, 33°26'48.00" N, 139°42'42.00" E to 33°27'0.00" N, 139°42'24.00" E, 200–211 m depth, from R / V Shinyo-maru, 21 Oct. 2003 (NSMT-TeS28); several branches of colony collected by NSMT, southwest of Boso Peninsula, ~ 34°51' N, 139°40' E, 135–172 m depth, from R / V Shinyo-maru, 25 Oct. 2002 (NSMT-TeS29); several branches of colony, Oshima Shin-sone, 28°52'24.60" N, 129°33'5.40" E to 28°53'1.20" N, 129°33'5.40" E, 169–172 m depth, with biological dredge from T / V Toyoshio-maru, collected 24 May 2011 (NSMT- Te780); several branches of colony, Oshima Shin-sone, 28°52.511' N, 129°33.233' E to 28°52.631' N, 129°33.313' E, 165–200 m depth, with biological dredge from T / V Toyoshio-maru, collected 29 May 2012 (NSMT-Te807).

Measurements

Autozooids. ZL: 593̅865 (743±89); ZW: 283̅366 (323±26); n = 21. SOrL: 54̅112 (81±14); SOrW: 84̅114 (102±8); n = 25. SAvL: 40̅82 (58±10); SAvW: 21̅46 (34±6); n = 51. SpL: 23̅45 (33±6); SpW: 23̅40 (33±4); n = 38.

Gonozooids. ZL: 566̅865 (659±91); ZW: 382̅463 (420±19); n = 19. SOrL: 60̅104 (78±15); SOrW: 118̅132 (123±5); n = 11.

Vicarious avicularia at branch margins. L: 189–224 (209±14); W: 111–125 (118±6); n = 7.

Additional small frontal avicularia in middle and basal parts of branch. L: 99–114 (106±6); W: 46–63 (55±5); n = 10.

Description

Colony yellowish white, dichotomously branching. Branches flat, slender, 2.607 –4.433 mm wide (average 3.3 mm; n = 10); ( Fig. 14A ). Autozooids on both sides of branches. Autozooids oval, distinct, delineated by deep groove ( Fig. 14 B–C). Frontal shield umbonuloid ( Fig. 10B ). Frontal shield smooth or with minute granules or wrinkles; with single row of marginal pores. Peristome deep, secondary orifice transversely oval. Spiramen in center of frontal shield; monoporous, circular ( Figs 14D , 15A ), rarely divided into two or three non-denticulate pores. Two to six tiny, irregular frontal pores proximal to orifice; roughly same size as marginal pores ( Figs 14 C–D, 15A). Small suboral avicularium ( Figs 14D , 15A, C ) just distal to and often abutting spiramen; rostrum short, with triangular mandible; separated from orifice by distance up to several times greater than mandible length; directed distally. Additional small frontal avicularia lacking in younger part of branch ( Fig. 14C ). Vicarious avicularia present ( Fig. 15 C–D); marginal, almost three times length of suboral avicularia; with triangular mandible. In middle and basal parts of colony, autozooids somewhat irregular in shape; borders indistinct; 572–774 μm long (average 665 μm) by 238–328 μm wide (average 274 μm) (n = 12); frontal shields heavily secondarily calcified; orifice nearly circular, 76–93 μm long (average 85 μm) by 73–115 μm wide (average 90 μm) (n = 8). In basal autozooids, spiramen consists of small single pore, 26–33 μm (average 30 μm) long by 23–31 μm wide (average 27 μm) (n = 4); suboral avicularia slightly larger than in non-basal zooids, 107–122 μm long (average 112 μm) by 41–47 μm wide (average 44 μm) (n = 5); spiramen and suboral avicularia submerged in common depression in heavily calcified frontal shield.Autozooids in middle and basal parts of branch bear additional small frontal avicularium, often on proximal margin of zooid ( Fig. 15A, C ); directed proximally or proximolaterally. Basal part of colony consists of irregularly shaped kenozooids that bear several small frontal avicularia ( Fig. 15B ). Gonozooids ( Fig. 14 C–D) slightly broader than autozooids; orifice crescentic, much wider than long, with convex proximal margin; spiramina and suboral avicularia roughly same size as in autozooids.

Remarks

Adeonellopsis parvirostrum sp. nov. fits the original description of Adeonellopsis japonica in having a small, circular spiramen and small suboral avicularium, but its avicularium is much smaller than in the latter. Young autozooids of A. parvirostrum sp. nov. lack the striation perpendicular to the margin seen on the rim of young zooids of A. japonica . Adeonellopsis parvirostrum sp. nov. resembles A. lichenoides in the basal part of the colony (compare Fig. 5D with Fig. 15B ), but differs from the latter in the presence of a distally directed suboral avicularium between the orifice and spiramen in older parts of branches. Some small frontal avicularia are sparsely surrounded by the remains of associated areolae of original autozooids and/or kenozooids ( Fig. 15 A–C). Some of the specimens of A. parvirostrum sp. nov. I observed were pinkish, although this may have resulted from artificial staining of another organism, as other bryozoan colonies in the same bottle were also pinkish.

Distribution

Japanese Pacific waters: north of Hachijo-jima Island, Sagami Sea, and near Amami Oshima, at depths of 135– 213 m.

Figures

Fig. 10. Interior frontal shield. A. Adeonellopsis japonica (Ortmann, 1890) (NSMT-Te1052). B. A. parvirostrum sp. nov. (NSMT-Te807). Arrowheads indicate ring scar. SEM images. Scale bars: A = 50 μm; B = 25 μm.

Fig. 14. Adeonellopsis parvirostrum sp. nov. A. Colony branches from Oshima Shin-sone, N of Amami Oshima (NSMT-Te780). B. Distal end of branch (NSMT-TeS26). C. Young autozooids and some gonozooids (four of them are indicated with asterisks) at distal end of branch (NSMT-TeS26). D. Gonozooids with broad, curved orifice, small triangular avicularia, and small spiramen (NSMT- TeS26). A–B = photomicrographs; C–D = SEM images. Scale bars: A = 1 cm; B–D = 500 μm.

Fig. 15. Adeonellopsis parvirostrum sp. nov. A. Middle of branch, showing autozooids lacking suboral avicularium (NSMT-Te780). B. Kenozooids in old part of branch (NSMT-Te780). C. Autozooids and marginal vicarious avicularia at periphery of branch (NSMT-Te780). D. Lateral view of vicarious avicularium at branch bifurcation (NSMT-Te780). SEM images. Scale bars: A, C–D = 200 μm; B = 300 μm.

Fig. 5. Adeonella jahanai sp. nov. A. Branch bifurcation lacking vicarious avicularaia (NSMT- Te889, Okinawa). B. Branch bifurcation with vicarious avicularium (NSMT-Te749, off Yakushima). C. Vicarious avicularia on side of branch (NSMT-Te889, Okinawa). D. Old part of branch showing autozooids and kenozooids (NSMT-Te889, Okinawa). E. Gonozooids at periphery of branch (NSMT- Te889, Okinawa). F. Gonozooid at periphery of branch (NSMT-Te889, Okinawa). SEM images. Scale bars: A– D = 200 μm; E = 300 μm; F = 100 μm.