New sponge species from Seno Magdalena, Puyuhuapi Fjord and Jacaf Canal (Chile)

Abstract. Until now, only 177 species of sponges (Porifera) have been reported for Chilean coastal waters. Here we describe recent scuba diving surveys undertaken to improve our knowledge of the diversity of the sponge fauna of the Seno Magdalena, Puyuhuapi Fjord and Jacaf Canal in Chilean Patagonia. Despite these relatively harsh environments, our study yielded 23 species of Demospongiae, nine of which are new to science and described here: Hymerabdia imperfecta Bertolino, Costa & Pansini sp. nov., Axinella cylindrica Bertolino, Costa & Pansini sp. nov., Axinella coronata Bertolino, Costa & Pansini sp. nov., Biemna aurantiaca Bertolino, Costa & Pansini sp. nov., Biemna erecta Bertolino, Costa & Pansini sp. nov., Biemna typica Bertolino, Costa & Pansini sp. nov., Scopalina cribrosa Bertolino, Costa & Pansini sp. nov., Rhizaxinella strongylata Bertolino, Costa & Pansini sp. nov. and Darwinella pronzatoi Bertolino, Costa & Pansini sp. nov. One species, Hymedesmia (Stylopus) lissostyla (Bergquist & Fromont, 1988), is reported for the fi rst time for Chile.


Introduction
The southern tip of South America is of particular interest for ecological and biogeographic studies of marine organisms. The relative proximity of Antarctica makes this subantarctic coast a transitional zone between South America, Antarctica and the temperate Pacific area (Escribano et al. 2003).
The subantarctic inner shelf of southern Chile (41-55° S) is characterized by a complex system of fjords, channels, gulf, estuaries and bays, each affected by local physical processes that strongly modulate biological productivity (Iriarte et al. 2014). Patagonian fjords are influenced by saline subantarctic surface waters and freshwater input from the continent; these waters interact to form modified subantarctic waters characterized by sharp vertical and horizontal salinity gradients (Iriarte et al. 2014 and references therein). These fjords can, therefore, be considered transitional marine systems where marked contrasts in marine biodiversity and distribution can be observed (Escribano et al. 2003).
The fjords of Chilean Patagonia cover an area of nearly 240 000 km 2 in one of the least densely populated areas of the country (1-8 inhabitants per 10 km 2 ) (Pantoja et al. 2011). In the last three decades, however, the influence of anthropogenic activities on these mostly pristine terrestrial and aquatic ecosystems has increased. Exploitation of the natural resources of the region (fisheries, tourism) and the expansion of commercial salmon and mussel farming (Pantoja et al. 2011) are increasing the pressure on these fragile fjord ecosystems, and they now require enhanced scientific surveillance and protection.
The coastal waters of Chilean Patagonia host more than 1700 species of benthic animals (Häussermann & Försterra 2009). The biodiversity of filter-feeding organisms is of particular interest given the high levels of primary productivity and complex physico-chemical processes occurring in these ecosystems. For example, filter-feeding cnidarians (such as hydrozoans and anthozoans) have been extensively studied in Chilean fjords in recent decades because of their role within the benthic community and subsequent ecological importance (Försterra & Häussermann 2003;Häussermann 2006;Häussermann & Försterra 2007a, 2007bSinniger & Häussermann 2009).
The aim of the present work is to document the diversity of sponge fauna in Seno Magdalena, Puyuhuapi Fjord and Jacaf Canal (Chile) (Fig. 1) and thus to improve the understanding of benthic communities more generally in these coastal waters.

Material and methods
The study area is located within the Aysen Region of northern Chilean Patagonia (Fig. 1). The study focussed on Seno Magdalena, Puyuhuapi Fjord and Jacaf Canal (Fig. 1). Puyuhuapi Fjord -located in the Chilean XI region -extends to a length of 90 km and a maximum width of 7 km (Fig. 1). The mouth of the fjord connects to the larger Moraleda Channel, which opens into the Pacific Ocean, while the head of the fjord consists of a large bay, around 2 km wide, close to Puyuhuapi village. Within the COPAS Sur Austral Program, one area of focus is a sampling program designated to improve our knowledge of the richness of the Porifera in this area from the qualitative point of view.
Sampling was conducted in August 2016 through scuba diving. Twelve sites were chosen with depths of sampling ranging between 5 and 30 m. Sponges were mainly collected from rocky substrates and photographed in situ with a Canon Digital IXUS 900 Ti ( Fig. 1; Table 1). The specimens were fixed in 70% ethanol and processed by standard methods for sponge identification (Rützler 1978). Taxonomic decisions were made according to the revision of Demospongiae of Morrow & Cárdenas (2015) and the classification present in the World Porifera Database (WPD) (van Soest et al. 2020). Length and width of at least 30 spicules per type were measured for each species / specimen collected. Minimum, mean (in parentheses) and maximum values of spicule dimensions are reported. For a Scanning Electron Microscope (SEM) Vega3 TESCAN type LMU analyses, dissociated spicules and dried tissues were transferred onto stubs, and then sputter coated with gold. The type specimens of any proposed new species were entrusted to the Museo Civico di Storia Naturale G. Doria of Genoa (collection acronym MSNG). Spicule slides and the other examined specimens (paratypes) are deposited in the sponge collection of the Dipartimento di Scienze della Terra dell'Ambiente e della Vita (DISTAV), Università degli Studi di Genova. All the specimens collected during the campaign were marked by the code CILE number.

Results
In total, the survey collected 44 specimens of demosponges belonging to 23 species (  (Bergquist & Fromont, 1988) was reported for the first time in Chile. Axinella cylindrica was the species with the largest number of specimens (4) and was recorded at four sites ( Table 2). The site with the largest number of collected specimens (14) and species was site E in Seno Magdalena. The geographical distribution of the collected and described species is shown in Table 2
Skeleton. Choanosomal skeleton formed by bundles of long styles and tylostyles with heads embedded in basal layer of rhabdostyles and sinuous sub-tylostyles.

Habitat
Species lives on a rocky cliff at a depth of 25-30 m; Chilean fjords.

Remarks
Out of the nine species of Hymerhabdia previously described around the world (Table 3), none have been recorded along Chilean coasts. The only species of this genus from the Southern Hemisphere is Hymerhabdia oxeata (Dendy, 1924) recorded at a depth of 183 m in northern New Zealand. Hymerabdia imperfecta sp. nov. differs from H. oxeata in having a red colour whereas in H. oxeata the colour is dark brown. As to spicules, H. oxeata has oxeas whereas the new species has tylostyles and rhabdostyles that are not present in H. oxeata. Moreover, the styles of the new species are much larger (Table 3). A comparison with the other 8 species of Hymerhabdia (from the Atlantic Ocean and the Mediterranean Sea reported in Table 3) shows remarkable differences in presence or absence of spicules (oxeas, rhabdostrongyles, toxostrongyles) and in their shape and size.

Description
Habitus. All of the specimens have a regular cylindrical shape (5-7 cm high, ca 1 cm in diameter) (  Table 4.

Habitat
This species lives on a rocky cliff covered by coralline algae, at a depth between 15 and 20 m.

Remarks
We have recorded two new species of the genus Axinella and have therefore chosen to make a single discussion after their description.   Table 5 Etymology The new species is named after the crown of thin styles surrounding single tylostyles.

Description
Habitus. Fan shaped sponge, 2 cm high, very thin (2 mm maximum), with short basal stem. Surface very hispid with tufts of macroscleres coming out from surface ( Fig. 5A-B). Consistency hard but friable. Colour in life bright yellow ( Fig. 5A-B).
Skeleton. Plumose, formed by multi-spicular primary tracts, radiating from axis towards surface

Habitat
Recorded on rocky cliffs and walls covered by coralline algae, at a depth between 20 and 25 m.

Remarks
The attribution of A. cylindrica sp. nov. and A. coronata sp. nov. to the genus Axinella Schmidt, 1862 is based on the skeleton architecture characterised by a choanosomal skeleton differentiated in the axial (compressed or vaguely reticulated) and extra-axial (plumoreticulated) regions. The only species of this genus present on the Chilean coast is A. crinita Thiele, 1905. This species differs from the two newly described species in external shape (very ramified with cylindrical branches (Desqueyroux 1972)), absence of rhabdostyles (present in A. cylindrica sp. nov.) and presence of long thin styles with curved head (absent in A. coronata sp. nov.). In Table 5, the other geographically close species of Axinella and other species recorded in the Southern Hemisphere are reported. All of these species differ from A. cylindrica sp. nov. and A. coronata sp. nov. in the external morphology, and the type and size of spicules. Moreover A. cylindrica sp. nov. differs from all the other species in the presence of rhabdostyles (Table 5).

Description
Habitus. Cushion-shaped sponge, almost spherical, 3.5 cm in diameter and ca 2 cm thick. Canal system visible, converging towards round flush oscula. Surface slightly hispid, colour in life bright orange (Fig. 7A-B). Consistency soft and friable.

Habitat
Species lives at a depth of 20 m on a vertical wall.

Biemna erecta
The new species is named after its growth form.

Description
Habitus. Fan-shaped lamellar sponge, about 3 mm thick and 3.5 cm long, with basal peduncle. Surface very hispid caused by megascleres protruding from surface. Colour in life pale yellow, tending to orange (Fig. 9A-B). Consistency soft, compressible and friable in dry state.
Skeleton. Plumose skeleton formed by dense fibres of spicules whose extremities protrude through surface of sponge, resulting in hispid appearance (Fig. 9C). Choanosome differentiated into two regions composed of axial compressed and extra-axial plumose fibres (Fig. 9D-E). Basal peduncle formed by ascending central fibres with radial spicules (Fig. 9F).

Habitat
Species lives on a vertical wall at a depth of 20 m.

Remarks
We have recorded three new species of the genus Biemna and have therefore decided to make combined remarks after their description.   Table 6 Etymology The new species is named after its spicule complement typical of the genus.

Description
Habitus. Massive, cushion shaped sponge, rather regular, ca 2 cm long and 2 cm thick, with very hispid surface. Colour in life bright red, remaining unchanged out of the water. Sponge compressible and friable (Fig. 11A).

Habitat
Species lives on a rocky slope covered by coralline algae, at a depth between 15 and 20 m.

Remarks
The three new species, Biemna aurantiaca sp. nov., B. erecta sp. nov. and B. typica sp. nov., differ from each other primarily in their external morphology and colour (see descriptions above and Table 6). Regarding megascleres, B. aurantiaca sp. nov. has smaller styles and tylostyles than B. erecta sp. nov., while B. typica sp. nov. has only three categories of styles, with no tylostyles. Furthermore, the microscleres differ in size between the three new species which are, therefore, clearly distinguishable from each other. From the cold waters of the Southern Hemisphere, twelve species of the genus Biemna are known ( Table 6). Two of these have been reported on the Chilean coast: B. chilensis Thiele, 1905 and B. lutea Bertolino, Costa & Pansini, 2019. The new species described in the present study differ from these two species in the presence of more categories of styles and different forms of spicules. Additionally, only one category of raphids is present in B. chilensis (see Table 6). Biemna typica sp. nov. differs from all other Biemna listed in Table 6 in the presence of only one category of styles. Biemna erecta sp. nov. and B. aurantiaca sp. nov. have spicule complements similar to B. rhabderemioides Bergquist, 1961 andB. rhabdostyla Uriz, 1988, but the latter two species possess much smaller styles and subtylostyles (Table 6).
In conclusion, the three species described here (Biemna aurantiaca sp. nov., B. erecta sp. nov and B. typica sp. nov.) differ from each other in the size and shape of the spicules, and should be considered as new species.

Skeleton. Choanosomal skeleton consisting of bundles of thin styles entirely enclosed in spongin.
Dendritic fibres rising up from basal spongin plate. Low spicular density.

Habitat
Species lives at a depth of 20 m, on a rocky slope covered by coralline algae.

Remarks
From five species of the Scopalina genus known in the Southern Hemisphere (Table 7), only Scopalina bunkeri Goodwin, Jones, Neely & Brickle, 2011 has been recorded from Chilean coast by Bertolino et al. (2019). The new species differs from S. bunkeri in having a very spiky surface and by the presence of smaller styles (Table 7). Scopalina cribrosa sp. nov. differs from S. australiensis (Pulitzer-Finali, 1982) from Eastern Australia in its external morphology, having an erect habit, large body and spicule size, but much smaller styles (Table 7). Scopalina cribrosa sp. nov. differs from S. erubescens Goodwin, Jones, Neely & Brickle, 2011 from the Falklands / Malvinas in its pale pink colour, a conulose surface, and styles that are four times shorter than those of S. erubescens (Table 7). Scopalina cribrosa sp. nov. differs from S. hapalia (Hooper, Cook, Hobbs & Kennedy, 1997) from Australia both in the colour and the presence of strongyles, which are lacking in the new species. Finally, regarding species of the Southern Hemisphere, S. cribrosa sp. nov. differs from S. incrustans (Lendenfeld, 1887) from Australia by its larger styles. The nine species of Scopalina reported from the Northern Hemisphere differ from S. cribrosa in the size of spicules, and often in their shape (Table 7). We, therefore, propose that Scopalina cribrosa sp. nov. should be considered as a species new to science.

Etymology
The new species is so named for the presence of strongyloid styles in the spicules.
Skeleton. Stalk characterized by axial compact skeleton that diverges into thinner secondary axes in branches. Close to surface ectosomal skeleton composed of brushes of spicules.

Habitat
Species lives at a depth between 20 and 25 m on a vertical wall.

Remarks
Only one species of this genus has been reported from the channels and fjords of southern Chile: Rhizaxinella spiralis (Ridley & Dendy, 1886). The new species R. strongylata sp. nov. described here differs from R. spiralis in external morphology, shape and size of styles / tylostyles, and in the presence of strongyloid spicules. In fact, R. spiralis has a stipitate cylindrical shape and two categories of tylostyles / styles that measure 1000 × 13 μm and 400 μm (width not reported in original description).

Emended diagnosis
In the Darwinella, the dendritic fibre skeleton is supplemented by fibrous spicules which can be diactinal, triactinal or polyactinal. There is no sand in the fibres but dispersed cellular elements can occur. The sponges are fleshy, encrusting, or massive to lobate; to which fibrous spicule with style shape may be added (emended from Müller 1865).

Remarks
The species of Darwinella may be confused with those belonging to the genus Aplysilla Schulze, 1878 because of the similarity in external shape; however, Darwinella is characterized by the presence of diactinal, triactinal or polyactinal fibrous spicules (Pronzato 1975). In the present study we described a new fibrous spicule type for the Darwinella genus. Bertolino, Costa & Pansini sp. nov. urn:lsid:zoobank.org:act:FA17C8DB-1973-4E6F-9AB9-A025F68D38F5 Fig. 15 Etymology

Darwinella pronzatoi
The new species is named after Professor Roberto Pronzato (DISTAV -Università degli Studi di Genova) in recognition of his significant contributions to taxonomic studies on horny sponges.

Habitat
Species lives at a depth of 15 m in a shady area on rocky wall.

Remarks
Up to now, there was no evidence of the presence of the genus Darwinella from the Chilean coasts. Thirteen species belonging to this genus have been described worldwide, eleven of which have multiradiate spicules and one species, Darwinella tango (Poiner & Taylor, 1990), has no spicules. Only two species are characterized by monaxonic spicules: D. gardineri Topsent, 1905, characterised by curved horny oxeas (1600-2000× 20 μm), and D. oxeata Bergquist, 1961, having horny spined oxeas (530-2083. Due to the presence of smooth, straight, slightly curved or sinuous horny styles, D. pronzatoi is clearly different from both these species, therefore it should be considered as a species new to science.

Discussion
With 23 identified species the present study notably increases the number of sponges reported from Chilean fjords to 139 (Table 8).
From a biogeographic standpoint, apart from the nine new species, one species, Biemna lutea Bertolino, Costa & Pansini, 2019, is recorded for the first time after its description in the same region; 12 species were already recorded from the Chilean coast; and one species, Hymedesmia (Stylopus) lissostyla described from New Zealand, is recorded for the first time in the Chilean sponge fauna (Table 2).
Taking into account the literature together with our data, the total number of sponge species known along the Chilean coasts, increases to 187 (Table 8).
The sponge fauna of the fjord region is strongly separated from that recorded in the other areas of the Chilean coasts. In fact, among the 139 species described for the fjords and the 73 listed for the Chilean coasts, only 25 are in common. This number clearly shows the peculiarity of the Southern Chilean coast and suggests the necessity of a further effort to achieve a satisfactory knowledge of the biodiversity of this area.     (Thiele, 1905) +