Murrayona phanolepis Kirkpatrick, 1910

Lopes, Matheus Vieira, Pérez, Thierry & Klautau, Michelle, 2024, Cave-dwelling calcareous sponges (Porifera: Calcarea) from the Marquesas Islands, French Polynesia, Zoological Journal of the Linnean Society (zlae 138) 202 (3), pp. 1-29 : 16-18

Murrayona phanolepis Kirkpatrick, 1910

( Figs 11, 12; Table 5 )

Type species: Murrayona phanolepis Kirkpatrick, 1910 .

Synonyms: Murrayona phanolepis Kirkpatrick 1910: 127 — Dendy and Row 1913: 741; Burton 1963: 569; Vacelet 1977: 348; Vacelet et al. 2002: 1154; Pérez et al. 2016: 297.

Type locality: Christmas Island, Indian Ocean .

Type material: Holotype: Christmas Island: BMNH 1954.6.3.4a, Christmas Island, approximately 84 m depth, 25.x.1908, coll. C. W. Andrews (‘Islander’).

Material examined: Marquesas Islands: UFRJPOR 7523 , Matateiko cave , Nuku Hiva (8°55.0 ʹ S, 140°13.0 ʹ W), 20 m depth, 11.i.2012, coll. T. Pérez, field number MQ3-GR-TP03. UFRJPOR 7525 , The Four Caves , Nuku Hiva (8°56.2 ʹ S, 140°07.2 ʹ W), 20 m depth, 11.i.2012, coll. T. Pérez, field number MQ2-GR-TP01. UFRJPOR 7527 , Hakaheteau cave , Ua Pou (9°23.7 ʹ S, 140°07.7 ʹ W), 10 m depth, 23.i.2012, coll. T. Pérez, field number MQ24-GR-TP02. UFRJPOR 7528 , Motuoio cave , Tahuata, (10°00.845 ʹ S, 139°07.345 ʹ W), 10-12 m depth, 15.i.2012, coll. T. Pérez, field number MQ11-GR-TP12. UFRJPOR 7529 , Matautu cave , Fatu Hiva (10°28.3 ʹ S, 138°40.6 ʹ W), 20 m depth, 17.i.2012, coll. T. Pérez, field number MQ15-GR-TP5 .

Colour: White to beige alive and in ethanol ( Fig. 11A).

Description: Sponge subspherical, globular or slightly flattened ( Fig. 11A). Consistency hard and harsh to the touch. The exhalant region is covered with scales, except for the oscula (one or two), which are surrounded by sagittal triactines ( Fig. 11B). No scales are present in the inhalant region ( Fig. 11C). Surface smooth and translucid, allowing observation of the canals. Atrium reduced to spaces within the hypercalcified skeleton. Aquiferous system leuconoid. The skeleton can be divided into two regions: one superficial composed of free spicules ( Fig. 11B–E) and a basal skeleton with a framework of hypercalcified sclerodermites ( Fig. 11F). The inhalant region is marked by regular triactines surrounding the inhalant apertures ( Fig. 11C). On the exhalant region, there are scales covering the cortex ( Fig. 11D) and diapason in bundles underneath the scales ( Fig. 11E). Trichoxeas are present on the external surface and among the hypercalcified basal skeleton.

Spicules ( Fig.12; Table 5 )

Oscular triactines: Sagittal. Actines cylindrical, undulated, with rounded tips. Paired actines much longer than the unpaired one ( Fig. 12A). Size (UFRJPOR 7525): 123.6 (±24.2)/7.9 (±1.4) µm (paired); 27.7 (±7.3)/8.7 (±1.6) µm (unpaired).

Triactines: Subregular. Actines cylindrical, undulated and commonly curved, with blunt to rounded tips ( Fig. 12B). Size (UFRJPOR 7525): 117.2 (±17.0)/11.5 (±2.7) µm.

Scales: As the actines are fused, this spicule is almost circular. It is either smooth or rugose at the external surface ( Fig. 12C). Younger forms, without the complete fusion of the actines, have sharp tips. Size (UFRJPOR 7525): 382.7 (±113.9) µm in diameter.

Diapasons: In these spicules, the paired actines are parallel to each other and opposed to the unpaired actine. Actines cylindrical and undulated, with rounded tips ( Fig. 12D). Commonly, one of the paired actines is curved and shorter than the other. Size (UFRJPOR 7525): 71.6 (±8.5)/6.1 (±1.2) µm (longer paired actines); 66.9 (±10.0)/9.5 (±1.7) µm (unpaired).

Ecology: Dense populations with patchy distribution in the collection sites at Marquesas. Depth ranges from 2 to 84 m ( Kirkpatrick 1910, Vacelet et al. 2010).

Geographical distribution: Christmas Island (type locality; Kirkpatrick 1910). Guam, Marianas Islands ( Hartman et al. 1980). Enewetak Atoll, Marshall Island ( Basile et al. 1984). Coral Sea, Australia ( Voigt et al. 2012). New Caledonia (Borojević et al. 2002). Tuamotu, Society, and Marquesas Islands, French Polynesia ( Vacelet 1977, Pérez et al. 2016; present study). Ecoregions: Cocos-Keeling/ Christmas Island, Marianas Islands, Marshall Islands, Coral Sea, New Caledonia, Tuamotus, Society Islands and Marquesas.

Remarks: Murrayona phanolepis was originally described from material collected on Christmas Island ( Kirkpatrick 1910). The specimens analysed on the original descriptions were collected in rocks brought by the anchor of the ship ‘Islander’. The description of the holotype matches that of our material from the French Polynesia. Murrayona phanolepis is considered a cosmopolitan species, with distribution ranging from Christmas Island (Eastern Indian Ocean) to French Polynesia (Pacific Ocean). Hypercalcified sponges are generally regarded as being morphologically conserved (e.g. Astrosclera willeyana Lister, 1900 ; Reitner and Engeser 1987, Reitner and Gautret 1996, Wörheide 2006). Yet, the p -distance found here between Marquesan and Australian specimens was relatively high for the C-LSU (1.5%; Voigt and Wörheide 2016, Klautau et al. 2020, 2022); therefore, M. phanolepis may be a species complex. Nonetheless, until studies on the connectivity of M. phanolepis populations are performed, we continue considering this wide distribution for this species.