Abyssocladia escheri, Ekins & Erpenbeck & Hooper, 2020

Ekins, Merrick, Erpenbeck, Dirk & Hooper, John N. A., 2020, Carnivorous sponges from the Australian Bathyal and Abyssal zones collected during the RV Investigator 2017 Expedition, Zootaxa 4774 (1), pp. 1-159 : 8-23

Abyssocladia escheri sp. nov.

Figure 2 , Tables 1 & 2

urn:lsid:zoobank.org:act:49779C5D-8130-4573-808D-1CAB9F5469CE

Material examined: Holotype: QM G337545 , off Fraser Island , Station 115, Queensland, Australia, 25 o 19’31.1”– 25° 21’ 4.7” S, 154 o 4’5.9”– 154° 4’ 33.6” E, 2350– 2342 m, Beam Trawl, Coll. Merrick Ekins on RV Investigator, Cruise IN2017_ V03 , Sample 115–126, 11/vi/2017.

Paratypes: QM G337546 off Fraser Island , Station 115, Queensland, Australia, 25 o 19’31.1”– 25° 21’ 4.7” S, 154 o 4’5.9”– 154° 4’ 33.6” E, 2350– 2342 m, Beam Trawl, Coll. Merrick Ekins on RV Investigator, Cruise IN2017_ V03 , sample 115–144, 11/vi/2017 ; QM G337506 same collection data as QM G337546, Sample 115–144.1 ; QM G337507 same collection data as QM G337546, Sample 115–144.2 .

Etymology: Named after the Dutch artist Mauritus Cornelis Escher, 1898–1972, for the shape of the abyssochelae resembling a 3D puzzle similar to something that Escher might have illustrated.

Distribution: This species is presently known only from the type locality off Fraser Island, Queensland, Australia, at abyssal depth.

Description: Growth form: Erect, pedunculate sponges up to 305 mm long and 20 mm thick at the widest part of the body, anchored in muddy substrate by a multi-furcate rhizoid basal root, with a club-shaped to conical, fleshy body and long, irregularly branching filaments that extend laterally at the apex of the sponge. The stem is up to 250 mm long and only 0.15 mm wide. The main body including filaments is 39 mm in length, and including the filaments 20 mm wide. The filaments themselves are up to 10 mm in length and 0.5 mm in width. The remainders of the basal rhizoid rootlets are 15 mm long and 0.3 mm wide.

Colour: Pale cream to orange on deck and beige in ethanol.

Ectosomal skeleton: The ectosome of both the stem and the filaments consists of soft tissue encrusted with abyssochelae.

Endosomal skeleton: The body, filaments and axis of the stem are composed of tightly bound, long, thin mycalostyles longitudinally arranged. The basal rhizoid rootlet also consists of longitudinally aligned axes of substrongyles that are shorter than those styles in the remainder of the sponge.

Megascleres: Mycalostyles in the filaments and stem are long, thin and straight with sharp points (615– 1280 x 7.0– 15.2 µm). Substrongyles from the roots are shorter and thicker, sometimes curved, often with blunt ends (92–555 x 3.4–16.7 µm) (see Table 2 ).

Microscleres: Abyssochelae with curved shaft (18.4–53.1 x 10.2–24.0 µm). In the smaller abyssochelae, the frontal and lateral alae are usually in contact with the alae offset from the opposing ones. In larger abyssochelae these alae become separated from those opposing alae. Abyssochelae of intermediate sizes were also present (see Table 2 ).

Molecular data: The 28S sequence of QM G337545 and G337546 are provided in the Sponge Barcoding Database under accession number SBD#2302, SBD#2303 respectively and the molecular difference to other congenerics displayed in Figure 3 .

Remarks: The presence of abyssochelae indicates this species belongs to the genus Abyssocladia . On gross morphology alone most species within this genus fall into three groups: ‘centipedes’ (feather-shaped), ‘bottlebrushes’ (short peduncle, large body), or ‘lollypops’ (with long pedunculate stems). The pedunculate species include A. bruuni Lévi, 1964 , A. carcharias Kelly & Vacelet, 2011 , A. claviformis Koltun, 1970 , A. desmophora ( Hooper & Lévi, 1989) , A. dominalba Vacelet, 2006 , A. fryerae Hestetun et al., 2019 , A. huitzilopochtli Vacelet, 2006 , A. inflata Vacelet, 2006 , A. kellyae Hestetun et al., 2019 , A. lakwollii Vacelet & Kelly, 2014 , A. marianensis Hestetun et a l., 2019, A. natushimae Ise & Vacelet, 2010 , A. oxeata Koltun, 1970 , A. polycephalus Hestetun et al., 2016 c , A. stegosaurensis Hestetun et al., 2019 and A. villosa . Abyssocladia that resemble ‘centipedes’ include: A. atlantica Lopes & Hajdu, 2014 , A. corniculiphora Hestetun et al., 2017a , A. diegoramirezensis Lopes et al., 2011 , A. faranauti Hestetun et al., 2015 , A. leverhulmei Goodwin et al., 2017 , A. myojinensis Ise & Vacelet, 2010 , A. naudur Vacelet, 2006 , A. tecta Hestetun et al., 2015 , and A. umbellata Lopes et al., 2011 . The third group, resembling ‘bottlebrushes’, include A. boletiphora Hestetun et al., 2017a , A. flagrum ( Lehnert et al., 2006) , A. hemiradiata Hestetun et al., 2017a and A. symmetrica ( Ridley & Dendy, 1886) . There is a solitary species that has a ‘bush-shaped’ anastomosing branched morphology representing multiple peduncles: A. koltuni ( Ereskovsky & Willenz, 2007) .

Abyssocladia escheri sp. nov. is unique amongst this genus in its relatively large size (up to 30 cm total length, exceeded only by A. flagrum from the Aleutian Islands, which measures 54 cm in length); having reduced spiculation consisting only of styles as megascleres and abyssochelae as microscleres; and comparative spicule dimensions (see Table 1 ). The abyssochelae of A. escheri sp. nov. resemble in shape those of A. natushimae from the North Pacific. However the abyssochelae in this new species are much smaller than those of A. natushimae (18.4-(29.3)- 53.1 µm vs. 38-(54)- 75 µm, respectively), and additionally A. escheri sp. nov. lacks the sigmancistras and microstrongyles that are present in A. natushimae .

Figures

FIGURE 2. Abyssocladia escheri sp. nov. A. Abyssochelae. B. Mycalostyle. C. Magnified ends of the mycalostyle depicted in B. D. Substrongyles styles from the basal rhizoid rootlets. E. Magnified ends of the substrongyle depicted in D. F. Paratype QM G337506. G. Paratype QM G337507. H. Holotype QM G337545. I. Paratype QM G337546. J. SEM of the filaments showing the abyssochelae in the ectosome and the mycalostyles. K. SEM of the root like processes showing the substrongyles longitudinally arranged.

FIGURE 3. Maximum-likelihood phylogram of the DNA sequences of this study in comparison with other, published cornivorous sponges. Sequences from taxa of this study are in bold. Number at the branches are RAxML rapid bootstrap values. Numbers following the taxa are either QM registration numbers (QM G3xxxxx) or NCBI Genbank accession numbers. Scale bare are substitutions per site. Please note that the reconstruction does not represent a phylogeny as due to the variability of the 28SrRNA gene C-Region barcoding marker no unambiguous alignment is possible and clipping ambiguous sites would remove diagnostic characters for taxon distinction. The tree therefore indicates molecular differences rather than a robust phylogeny.

Tables

TABLE 1. Comparative morphological and distributional data for all known species of Abyssocladia.

Species	Reference Morphology	Total height x width (mm)	Skeleton	Spicules of main axis (LxW μm)	Spicules of lateral filaments or body (LxW μm)	Spicules of basal attachment (LxW μm)	Chelae (L μm)	Sigmancistr as (L μm)	Sigmas Locality, (L μm) depth range and other microscleres
Abyssocladia escheri sp. nov.	this work ‘Pedunculate’, erect, with long very thin stem, multi-furcate root-like basal holdfast processes, and club-shaped to conical body with irregular lateral filaments	305 x 20	‘Pedunculate’, body and filaments supported by longitudinal bundles of longer styles, basal root-like processes with longitudinally aligned shorter style, stem contains both types of styles but mainly the shorter ones	shorter styles 92–555 x 3.4–16.7	longer styles 615–1280 x 7.0–15.2	shorter styles 92–555 x 3.4–16.7	Abyssochelae 18.4–53.1 x 10.2–24.0	absent	absent	off Fraser Island, Queensland, Australia, bathyal
Abyssocladia annae sp. nov.	this work ‘Pedunculate’, erect stem supporting a slightly cupped- shaped obovate (leaf-like, flabellate, fan-shaped) apical body, lacking lagteral filaments	3 x 2	Peduncle axis longitudinally arranged subtylostyles, body with radiating subtylostyles projecting only in one quadrant	subtylostyles 288-(504)-1000 x 3.1-(7.4)-15.2	undifferentiated	absent	Abyssochelae 48.2-(60.6)-72.2 x 5.1-(9.7)-14.9	11.6-(15.6)- 18.5	absent	off the continental shelf of central New South Wales, Australia, abyssal
Abyssocladia gliscofila sp. nov.	this work ‘Pedunculate’, erect, long thin stem, inflated filaments increasingly longer towards the apex, furcate root-like basal holdfast with fine basal rootlets anastomosing from roots	120–130 x 0.15–1.0	Peduncle axis, filaments and upper basal holdfast roots tightly bound longitudinal tracts of mycalostyles, axis of basal rootlets tightly bound longitudinal tracts of styles.	Mycalostyles 319–1560 x 2.0–22.7	undifferentiated	Styles 179–470 x 4–10.2	Arcuate isochelae 22.4–42 x 1.5–7	absent	absent	continental slope adjacent to the central and northern New South Wales coast, Australia, mesophotic -bathyal

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TABLE 2. Spicule dimensions (µm) of the holotype and paratypes of Abyssocladia escheri sp. nov.

Specimen	Abyssochelae	Mycalostyles	Substrongyles
QM G337545 Holotype	18.4-(31.1)-53.1 x 10.0-(15.9)-23.5, n=140	745-(979)-1180 x 7.0-(9.8)-13.4, n=53	92-(346)-531 x 3.4-(7.4)-12.9, n=59
QM G337506 Paratype	20.0-(27.9)-48.1 x 10.9-(15.2)-24.0, n=41	712-(997)-1180 x 6.0-(10.6)-15.2, n=44	271-(424)-555 x 4.7-(8.3)-11.9, n=32
QM G337507 Paratype	21.6-(30.8)-45.0 x 11.6-(16.0)-22.0, n=29	615-(998)-1280 x 6.0-(9.8)-15.2, n=41	261-(384)-551 x 4.6-(10.7)-14.3, n=40
QM G337546 Paratype	19.3-(27.1)-44.7 x 10.2-(15.2)-23.4, n=39	632-(902)-1050 x 5.9-(9.1)-12.3, n=38	118-(314)-484 x 4.7-(7.4)-16.7, n=36