Hyalopale bispinosa Watson & Tilic & Rouse 2019, sensu stricto

Hyalopale bispinosa sensu stricto Perkins, 1985 sensu stricto

Figs 1A; 2

Hyalopale bispinosa Perkins, 1985: 908, Figs 28 A–F, 29 A–H

Type locality. Southern Florida, West Atlantic Material examined. Paratype. Hyalopale bispinosa sensu stricto. USNM 097369, specimen designated as paratype by Perkins ( 1985), 1 individual in 2 pieces, 17NE (original description 20 segments entire), L: 2mm, W: 0.8mm. North Atlantic Ocean, Florida, Dade County, S Biscayne Bay, Turkey Point power plant, east of Florida Power & Light Company, Thalassia bed, coll. FOER personnel, 15 Feb 1978.

Additional material. H. bispinosa s.s. LACM – AHF 2879, Caribbean Sea, Bahamas, Great Bahama Bank, Exhuma Cays, 23° 28’N, 75° 45’ W, Basil Minn’s cave, marine entrance pool, bottom algae & sediment, strong hydrogen sulphide odor from black silt, coll. T. Iliffe & L. Harris, 11 Jan 2003. 1, 17NE, with gametes, L: 2.75mm, W: 1.25mm; LACM-AHF 2874, Bahamas, Great Bahama Bank, Exhuma Cays, Stocking Cay, 23° 31’ 21” N, 75° 45’ 21” W, Stn. 32, beneath ledge adjacent to cave entrance, 1m, coll. T. Haney & L. Harris, 9 Jan 2003, 2NE: anterior end 12 segments, anterior end 7 segments, ovigerous female with mature eggs, 2 per body segment, body starting to degenerate, neurochaetae falling out.

Diagnosis. Hyalopale with mid-body main paleae with sloping convex margin, 26/27 (29) ribs, raised ribs absent.

Description. ( based on Florida paratype USNM 097369).

Pale body covered in glass-like notochaetal paleae with reflective shine. Segment II notopodia with four spines each. Mid-body notochaetal fan comprises: lateral spine, nine main paleae, single short midline spine. Lateral-most main paleae with 21/22 ribs, middlegroup main paleae with 26/27 (29) ribs, shorter, slightly symmetrical midlinemost main palea with 19 ribs. Slender dorsal cirri just under half length of main fan. Main paleae with sloping convex margin, with very fine margin serration, inner margin with no visible serration, internal ribs densely packed with no obvious raised ribs, apices small, only slightly peaked (Fig. 1A). Mid-body neuropodia with falcigerous neurochaetae comprising: four superior long-bladed, two mid-superior long-bladed, 15–18 mid-group, 6–8 inferior falcigers; slender ventral cirri under half the length to neuropodial tip.

Remarks. Perkins (1985) figured in some detail the type material comprising mature individuals of Hyalopale bispinosa from the Florida mainland coast (Figs 28 A–F, 29 A–H). Perkins’ generic diagnosis states main paleae with ‘more than 25 internal ribs’ and remarks state ‘about 25 internal ribs’ (1985:908). The holotype was not examined for this study, but it is clear based on Perkins’ description and figures that the larger-bodied holotype and paratype material constitute H. bispinosa s.s. Examination of paratype material from the same locality as the holotype reveals an individual with a range of number of ribs with the middle group main paleae group numbering 26–28 (29) and lower numbers, 19–22, possessed by slender lateral and midline-most main paleae. Smaller paratypes collected from the Florida Keys, and designated as ‘young specimens’ by Perkins, are now described as a new species (see H. leslieae sp. nov.).

Additional material was made available of Hyalopale bispinosa s.s. from the Bahamas, including a live, entire individual with a yellow body and internal green pigmented patches (Fig. 2). This specimen has nine main paleae with (24) 25–26, 28 (29) ribs and another specimen has 8–10 main paleae with 27–30 ribs and slender lateral and midline main with 24/25 ribs; paleae of both specimens exhibit no obvious raised ribs. H. bispinosa s.s. material from mainland Florida and the Bahamas share common characters: similar length of body and number of segments, distinctive slope of brow of main paleae, absence of raised ribs as well as possession of the highest number of paleal ribs, a character which separates H. bispinosa s.s. from all other species. The type locality habitat was recorded as hard benthic and algal substrates (Perkins 1985). The Bahamas habitats refer to ‘bottom algae and sediment’ and a description of ‘black silt with a strong hydrogen smell’ indicating an anoxic habitat. Depths of 0–2m are recorded.