Diphasia margareta ( Hassall, 1841 )

Gil, Marta & Ramil, Fran, 2017, The genus Diphasia L. Agassiz, 1862 (Cnidaria, Hydrozoa) in Northwest Africa, Zootaxa 4363 (3), pp. 301-349 : 309-321

Diphasia margareta ( Hassall, 1841)

( Figs. 4–7 ; Table 3)

? Sertularia pinaster Ellis & Solander, 1786: 55 –56, pl. VI, fig. 13B [Not Sertularia pinaster Lepechin, 1783 = Thuiaria pinaster (Lepechin, 1783) ].

? Sertularia pinastrum: Cuvier, 1830: 301 (incorrect subsequent spelling).

Sertularia margareta Hassall, 1841: 284 , pl. VI, figs. 3 – 4.

Diphasia pinaster: Hincks, 1868: 252 –253, pl. L, fig. 1; Cornelius, 1995: 50 –53, fig. 10.

Diphasia elegans G.O. Sars, 1874: 107 –108, tab.III, figs. 23–26.

Diphasia margareta: Cornelius, 1979: 263 –265, fig. 11; Ramil & Vervoort, 1992: 201 –210, figs.52, 53, 54, 55, 56C–E, 57A, 58.

Not Diphasia pectinata: Vervoort, 1959: 255 –256, figs. 23–24 (= Diphasia africana n. sp.) [Not Diphasia pectinata ( Lamarck, 1816) = Diphasia nigra ( Pallas, 1766) ].

Not Diphasia pinaster: Billard, 1907: 357 –358 (= Diphasia heurteli Billard, 1924 ).

Material examined. Morocco. MAROC-0411, stn MO09, 35º29´34"– 35º32´40"N, 7º15´13"– 7º18´25"W, 1228– 1198 m, 16-XI-2004: two colonies 29 and 77 mm high, no gonothecae.

MAROC-0411, stn MO14, 35º31´08"–35º29´25"N, 6º27´51"–6º27´17"W, 720–724 m, 18-XI-2004: three colonies 18–25 mm high, one attached to Polyplumaria flabellata and other attached to Nemertesia ramosa , one with two male gonothecae.

MAROC-0411, stn MO33, 34º35´12"–35º00´44"N, 7º13´58"–7º15´16"W, 1248– 1236 m, 24-XI-2004: single colony 21 mm high, no gonothecae.

MAROC-0411, stn MO34, 35º10´11"–35º10´03"N, 6º32´35"–6º32´30"W, 762–763 m, 25-XI-2004: two colonies 41 and 69 mm high, no gonothecae.

MAROC-0411, stn MO35, 35º08´45"–35º06´45"N, 6º27´21"–6º27´11"W, 583–598 m, 25-XI-2004: single colony 60 mm high, no gonothecae.

MAROC-0411, stn MO43, 34º14´52"–34º16´40"N, 7º01´56"–7º01´26"W, 936– 929 m, 28-XI-2004: single colony 26 mm high, no gonothecae.

MAROC-0411, stn MO44, 34º20´09"–34º19´22"N, 7º07´11"–7º07´45"W, 1426– 1414 m, 28-XI-2004: single colony 86 mm high, no gonothecae.

MAROC-0411, stn MO48, 34º11´55"–34º11´22"N, 7º15´25"–7º17´21"W, 841–842 m, 29-XI-2004: single colony 119 mm high, no gonothecae.

MAROC-0411, stn MO63, 33º12´05"–33º10´18"N, 9º09´59"–9º09´30"W, 577–620 m, 5-XII-2004: one fragment 24 mm high, no gonothecae.

MAROC-0411, stn MO72, 31º32´56"–31º33´53"N, 10º08´07"–10º08´46"W, 516–553 m, 7-XII-2004: twenty one colonies 15–130 mm high, one colony attached to Acryptolaria conferta minor and other attached to a fishing line, three colonies with female gonothecae and one with male gonothecae.

MAROC-0411, stn MO74, 31º20´16"–31º18´35"N, 10º09´00"–10º09´13"W, 644–666 m, 8-XII-2004: single colony 23 mm high, no gonothecae.

MAROC-0411, stn MO78, 31º11´51"–31º11´49"N, 10º18´10"–10º16´07"W, 578– 500 m, 9-XII-2004: single colony 29 mm high, with male gonothecae.

MAROC-0511, stn MO148, 27º52´56"–27º50´39"N, 13º26´43"–13º28´15"W, 704–744 m, 1-XII-2005: three colonies 54–82 mm high, no gonothecae.

Western Sahara. MAROC-0611, stn MO189, 21º09´04"– 21º12´24"N, 17º42´06"– 17º42´18"W, 564– 556 m, 14-XI-2006: four colonies 16–80 mm high, no gonothecae.

MAROC-0611, stn MO201, 21º39´26"–21º42´13"N, 17º33´09"–17º31´25"W, 736– 734 m, 18-XI-2006: single colony 30 mm high, no gonothecae.

MAROC-0611, stn MO205, 21º50´30"–21º53´17"N, 17º26´12"–17º24´20"W, 311–358 m, 19-XI-2006: two colonies 30 and 102 mm high, one colony with female gonothecae.

MAROC-0611, stn MO213, 22º08´22"–22º10´10"N, 17º32´33"– 17º30´09"W, 919– 893 m, 21-XI-2006: single colony 82 mm high, no gonothecae.

MAROC-0611, stn MO214, 22º05´32"–22º08´22"N, 17º27´32"–17º26´20"W, 596– 583 m, 21-XI-2006: single colony 34 mm high, no gonothecae.

MAROC-0611, stn MO222, 22º39´35"–22º43´05"N, 17º13´19"–17º12´35"W, 410–414 m, 23-XI-2006: two colonies 22 and 41 mm high, no gonothecae.

MAROC-0611, stn MO225, 22º43´25"–22º45´24"N, 17º16´13"–17º13´24"W, 698– 604 m, 24-XI-2006: two colonies 20 and 39 mm high, no gonothecae.

MAROC-0611, stn MO253, 23º50´31"–23º54´19"N, 16º50´27"–16º48´34"W, 463– 459 m, 3-XII-2006: single colony 73 mm high, no gonothecae.

Mauritania. MAURIT-0811, stn MU128, 16º33´15"– 16º31´09"N, 16º48´07" –16º48´27"W, 218–404 m, 1- XII-2008: four colonies 49–143 mm high, no gonothecae.

MAURIT-0811, stn MU130, 16º44´31"–16º47´12"N, 16º46´48"–16º47´01"W, 252–362 m, 2-XII-2008: single colony 109 mm high, no gonothecae.

MAURIT-0811, stn MU131, 17º00´55"–17º03´33"N, 16º43´21"–16º41´50"W, 102–104 m, 2-XII-2008: seven colonies 56–187 mm high, no gonothecae.

MAURIT-0811, stn MU142, 18º09´13"–18º12´29"N, 16º28´17"–16º28´34"W, 109–112 m, 5-XII-2008: single colony 77 mm high, no gonothecae.

MAURIT-0811, stn MU145, 18º26´47"–18º29´45"N, 16º36´14"–16º36´42"W, 232– 230 m, 5-XII-2008: single colony 38 mm high, no gonothecae.

MAURIT-0811, stn MU147, 18º41´01–18º38´04"N, 16º34´31"–16º33´14"W, 134–139 m, 6-XII-2008: single colony 75 mm high, no gonothecae.

MAURIT-0811, stn MU148, 18º42´02"–18º39´56"N, 16º36´28"–16º38´29"W, 215–245 m, 6-XII-2008: single colony 96 mm high, no gonothecae.

MAURIT-0811, stn MU151, 18º49´50"–18º52´17"N, 16º38´03"–16º39´59"W, 110–134 m, 7-XII-2008: seven colonies 62–132 mm high, no gonothecae.

MAURIT-0811, stn MU152, 18º50´25"–18º53´35"N, 16º48´58"–16º49´03"W, 381– 316 m, 7-XII-2008: single colony 65 mm high, no gonothecae.

MAURIT-0811, stn MU159, 17º37´55"–17º41´01"N, 16º34´30"–16º34´24"W, 224–229 m, 9-XII-2008: single colony 46 mm high, no gonothecae.

MAURIT-0911, stn MU184, 19º29´44"–19º28´06"N, 17º01´19"–17º00´43"W, 213– 202 m, 18-XI-2009: two colonies, 125 and 130 mm high, no gonothecae.

MAURIT-0911, stn MUBV08, 20º44´50"–20º45´03"N, 17º38´47"–17º38´37"W, 174– 168 m, 26-XI-2009: three colonies 88–99 mm high, no gonothecae.

MAURIT-0911, stn MUBV14, 16º46´02"–16º45´49"N, 16º47´36"–16º47´33"W, 300– 281 m, 3-XII-2009: five colonies 15–18 mm high, no gonothecae.

MAURIT-0911, stn MU219, 16º12´13"–16º13´35"N, 16º50´28"–16º50´01"W, 125–129 m, 6-XII-2009: single colony 66 mm high, no gonothecae.

MAURIT-0911, stn MUBV19, 18º27´35"–18º27´22"N, 16º38´02"–16º37´58"W, 306 m, 11-XII-2009: nine colonies 21–130 mm high, no gonothecae.

MAURIT-0911, stn MUBV20, 18º28´16"–18º28´02"N, 16º32´37"–16º32´32"W, 155 m, 12-XII-2009: four colonies 83–115 mm high, no gonothecae.

MAURIT-0911, stn MU233, 18º44´26"–18º43´50"N, 16º37´12"–16º38´48"W, 165–189 m, 13-XII-2009: 64 colonies 49–275 mm high, no gonothecae.

MAURIT-0911, stn MU235, 19º01´34"–19º00´00"N, 16º41´55"–16º42´04"W, 123 m, 14-XII-2009: five colonies 65–145 mm high, no gonothecae.

MAURIT-1011, stn MU290, 18º16´53"–18º18´44"N, 16º35´23"–16º35´35"W, 311 m, 14-XII-2010: 21 colonies 22–131 mm high, no gonothecae.

MAURIT-1011, stn MUDR11, 19º38´25"N, 17º06´52"W, 322 m, 26-XI-2010: 64 colonies 23–54 mm high, no gonothecae.

MAURIT-1011, stn MUDR14, 19º36´53"N, 17º04´15"W, 243 m, 27-XI-2010: two colonies 50 mm high, no gonothecae.

Cape Verde Islands. CCLME-2011, stn SL-6, 23º06´6"N, 15º51´88"W, 107 m, 11-VI-2011: one colony 18 mm high, no gonothecae.

Guinea Bissau. BISSAU-0810, stn BS132, 11º31´33"N, 17º14´07"W, 23-X-2008: four colonies 39–60 mm high, three colonies attached to worm tubes, no gonothecae.

BISSAU-0810, stn BS133, 11º29´17"–11º28´26"N, 17º15´14"–17º15´14"W, 733–734 m, 23-X-2008: seven colonies 29–63 mm high, one colony attached to a scleractinian coral, six colonies attached to worm tubes; no gonothecae.

BISSAU-0810, stn BS134, 11º28´17"–11º29´11"N, 17º13´12"–17º13´22"W, 385– 374 m, 23-X-2008: three colonies 65–115 mm high, no gonothecae.

BISSAU-0810, stn BS147, 11º08´35"–11º08´27"N, 17º11´31"–17º10´37"W, 306– 186 m, 26-X-2008: six colonies 44–83 mm high, no gonothecae.

BISSAU-0810, stn BS152, 10º31´12"–10º30´19"N, 17º12´34"–17º12´32"W, 300–305 m, 27-X-2008: 223 colonies 15–119 mm high, 22 colonies attached to Lytocarpia myriophyllum , one colony attached to Nemertesia ventriculiformis one colony attached to Nemertesia sp., one colony attached to a worm tube; 37 colonies with female gonothecae and 25 colonies with male gonothecae.

BISSAU-0810, stn BS157, 10º19´36"–10º18´44"N, 17º10´29"–17º10´12"W, 304–308 m, 28-X-2008: five colonies 45–78 mm high, two colonies attached to worm tubes, one colony with male gonothecae.

BISSAU-0810, stn BS173, 10º04´52"–10º04´17"N, 16º34´12"–16º33´30"W, 278– 277 m, 31-X-2008: two colonies 67– 50 mm high, no gonothecae.

Josephine Bank. SEAMOUNT-1, stn DW37, 36º42.0´N, 14º17.7´W, 255–270 m, 4-X-1987: four colonies 32– 65 mm high, no gonothecae.

SEAMOUNT-1, stn DW38, 36º41.5´N, 14º17.0´W, 235–245 m, 4-X-1987: five colonies 25–62 mm high, no gonothecae.

SEAMOUNT-1, stn CP40, 36º38.6´N, 14º15.9´W, 215–221 m, 4-X-1987: three colonies 29–53 mm high, no gonothecae.

SEAMOUNT-1, stn DW41, 36º40.1´N, 14º14.9´W, 200 m, 4-X-1987: single colony 84 mm high, no gonothecae.

SEAMOUNT-1, stn DW60, 36º43.1´N, 14º17.3´W, 240–255 m, 7-X-1987: single colony 45 mm high, no gonothecae.

SEAMOUNT-1, stn DW61, 36º40.2´N, 14º16.0´W, 200–205 m, 7-X-1987: single colony 37 mm high, no gonothecae.

Gorringe Bank. SEAMOUNT-1, stn DW06, 36º30.2´N, 11º37.9´W, 250 m, 22-IX-1987: two colonies 36–61 mm high, no gonothecae.

SEAMOUNT-1, stn CP11, 36º26.4´N, 11º40.2´W, 805–830 m, 23-IX-1987: single colony 34 mm high, no gonothecae.

SEAMOUNT-1, stn DW15, 36º33.4´N, 11º28.8´W, 300–330 m, 24-IX-1987: seven colonies 52–86 mm high, no gonothecae.

SEAMOUNT-1, stn DE20, 36º33.7´N, 11º30.1´W, 305–320 m, 24-IX-1987: six colonies 53–110 mm high, two colonies with male gonothecae, one colony with female gonothecae attached to Aglaophenia tubulifera .

SEAMOUNT-1, stn DW21, 36º34.9´N, 11º28.4´W, 460–480 m, 24-IX-1987: single colony 61 mm high, attached to Nemertesia sp., no gonothecae.

SEAMOUNT-1, stn DW34, 36º31.2´N, 11º32.2´W, 80–110 m, 3-X-1987: three colonies 50–93 mm high, no gonothecae.

Ampère Bank. SEAMOUNT-1, stn CP93, 35º03.7´N, 12º54.0´W, 140–230 m, 11-X-1987: nine colonies 24– 64 mm high, one attached to Nemertesia perrieri , one with male gonothecae, one with female gonothecae.

SEAMOUNT-1, stn DE95, 35º04.6´N, 12º55.3´W, 197–210 m, 11-X-1987: single colony 63 mm high, no gonothecae.

SEAMOUNT-1, stn DW97, 35º05.5´N, 12º54.1´W, 204–250 m, 12-X-1987: three colonies 28–51 mm high, no gonothecae.

SEAMOUNT-1, stn DE98, 35º03.2´N, 12º55.4´W, 300–325 m, 12-X-1987: ten colonies 34–63 mm high, one colony with male gonothecae, one with female gonothecae.

SEAMOUNT-1, stn CP99, 35º03.8´N, 12º55.4´W, 225–280 m, 12-X-1987: 16 colonies 19–85 mm high, two colonies with female gonothecae and one with male gonothecae.

SEAMOUNT-1, stn CP100, 35º03.6´N, 12º55.3´W, 182–207 m, 12-X-1987: twenty four colonies 15–84 mm high, one colony attached to Diphasia alata and two colonies attached to Aglaophenia tubulifera ; six colonies with male gonothecae, four colonies with female gonothecae.

Additional material. Norway. Møre og Romsdall , UMB Nr. 349, Prof. G.O. Sars, loc: Kristiansund (no further information provided in the label): two colonies 35–70 mm high, one of them attached to stone.

Hordaland. UMB Nr.259, loc. Mosterhamn Bømlo, Jul. 1887 (no further information provided in the label): one colony 30 mm high, attached to stone.

Hordaland, UMB Nr.301, Jul. 1887 (no further information provided in the label): two colonies 56–67 mm high, one with male gonothecae.

Spain. Galicia, Bares , 43º46´19´´N, 7º40´11´´W, March. One colony 11 mm high, without gonothecae stranded on beach.

Morocco. LMZ-109, BALGIM expedition, stn CP09, 36º47.6´N, 09º28´W, 1163 m, 29-V-1984: one slide with hydrocladia of 17 mm high.

LMZ-111, BALGIM expedition, stn CP26, 36º45.5´N, 07º08.4´W, 392 m, 31-V-1984: two slides, one with a fragment of 7 mm high and the other with a fragment of 12 mm high from the basal part of the colony, both without gonothecae.

Biology. This species was found on Sertularella cylindritheca ( Vervoort 1959) ; Nemertesia sp.; Streptocaulus pulcherrimus Allman, 1883 ; bryozoans; worm tubes; shells; small stones; rooted in the sediment by the hydrorhiza and as an epibiont on big and old colonies of D. margareta (Medel & Vervoort 1988) . Our material was growing on Acryptolaria conferta minor Ramil & Vervoort, 1992 ; Aglaophenia tubulifera (Hincks, 1861) ; Lytocarpia myriophyllum ( Linnaeus, 1758) ; Nemertesia ventriculiformis (Marktanner-Turneretscher, 1890) ; Nemertesia sp.; D. alata; scleractinians; worms tubes and fishing lines.

Fertile colonies were reported in March and May–September ( Ramil & Vervoort 1992; Cornelius 1979, 1995; Medel & Vervoort 1988). We found colonies with gonothecae between September and December.

Distribution. Diphasia margareta is widely distributed along the Northeastern Atlantic, from Norway to Guinea-Bissau, including the Mediterranean Sea ( Ramil & Vervoort 1992). The species has also been reported in Azores, Selvagens, Canary and Cape Verde Islands ( Medel & Vervoort 1998).

The material identified as Diphasia pinaster (= D. margareta ) from Mozambique by Billard (1907) was described later by the same author ( Billard 1924) as a new species: Diphasia heurteli Billard, 1924 . Stechow (1925) also reported the presence of D. margareta [as Nigelastrum (Diphasia) pinaster ] in the Mozambique Channel; however, the origin of the data is unclear. We assume that his record is based on Billard (1907) because D. margareta was never found again in those waters. Our material comes from Norway, Galicia (Northwest Spain), Josephine, Gorringe and Ampère banks, Morocco, Western Sahara, Mauritania, Cape Verde Islands and Guinea-Bissau.

Its bathymetric range extends from 24 ( Medel & Vervoort 1998) to 1318 m ( Ramil & Vervoort 1992). The present material was collected between 80 and 1426 m.

Description. Hydrorhiza composed of a network of perisarcal tubes adhering the colony to the substratum. Colonies composed of an erect and monosiphonic axis provided with pairs of opposite hydrothecae and lateral branches (hydrocladia), pinnately disposed and slightly directed to the frontal side of the colony. Axes are a little wider than the hydrocladia and may be divided into segments of different lengths by transverse nodes. Hydrocladia are inserted under an axial hydrotheca (fig. 4F) and separated, consecutively, by one and two pairs of hydrothecae; thus, between two consecutive hydrocladia on the same side, three hydrothecae are present. Hydrocladial hydrothecae disposed in subopposite pairs at the basal part but opposite distally. Hydrothecae tubular and located laterally on the axes and hydrocladia, adnate by one-third to half of the total length, and curved outwards. Free part of the adcauline wall long, straight or slightly concave distally, and usually with striae along its length; adnate part slightly concave. Abcauline wall with an internal perisarcal ledge of very variable development; beyond this ledge, the abcauline wall is curved upwards. Hydrothecal rim smooth, semicircular and closed by a single operculum attached to the adcauline sinus. Aperture of the hydrothecae directed upwards and almost perpendicular to the hydrocladia (figs. 4B, 5A).

Female and male gonothecae borne on the axes or hydrocladia of different colonies under a pair of hydrothecae; female bigger than male. Female gonotheca pear-shaped with apical part rounded and narrowing basally. Gonothecal wall with four longitudinal ribs along almost its entire length; each rib with two to six welldeveloped spines on the distal part. Inner apical part of the gonotheca with a well-developed marsupium communicated with the proximal gonothecal cavity by a circular aperture; two lateral funnels originating from both sides of the marsupium reach the gonothecal wall and form a pair of lateral openings (figs. 4C, 5B, 6B). The larvae develop inside the marsupium and leave the gonothecae through these holes. Male gonothecae disposed perpendicular to the axis or hydrocladia. They are narrow at the base, widening towards the distal part, where they are quadrangular in the cross-section and provided with four spines, one at each corner, surrounding a central aperture located at the end of a conical elevation (figs. 4D–E, 5C–D, 6C). In both female and male gonothecae, the spines are very variable in morphology and length.

Remarks. Diphasia margareta is currently considered a highly variable species characterized by the morphology of its gonothecae: the female provided with four external longitudinal ridges with a variable number of spines on each ridge and the male, quadrangular in the cross-section with one distal spine on each corner, surrounding a central aperture located at end of a conical elevation. Its variations were described in detail by Ramil & Vervoort (1992) and arranged in four major groups. All material studied by us is consistent with the second group: a more tubular hydrothecae provided with striae on the lateral walls and the female gonothecae showing always well-developed longitudinal ridges, each with spines oscillating between two and six. We found the same degree of variation described by Ramil & Vervoort (1992) in the materials studied in this report, and, therefore, we included it in D. margareta .

The nomenclature of the species was the subject of extensive discussions, and several names were proposed for it during the last century. Diphasia margareta was described by Hassall (1841) after collecting colonies from Ireland. In the original description, Hassall (1841) pointed out the resemblance of D. margareta with Sertularia pinaster Ellis & Solander, 1786 ; but differences in the morphology of the gonothecae led him to consider it a different species. It should be noted that the gonothecae described by Ellis & Solander (1786) were female and those described by Hassall (1841) were male.

Hincks (1868) concluded that D. margareta is the female colony of S. pinaster and included it as its synonym. Hincks’s opinion was widely shared in the 20th century (references in Medel & Vervoort 1998: 15–16).

Nevertheless, Vervoort (1959) indicated that Sertularia pinaster Ellis & Solander, 1786 is an invalid junior homonym of Sertularia pinaster Lepechin, 1781 [= Thuiaria pinaster (Lepechin, 1781) ] and included the Ellis & Solander species under the name Diphasia pectinata ( Lamarck, 1816) , which was considered by Bedot (1901: 442, 503) as a synonym of D. pinaster and, consequently, the first available name for D. margareta . However, the holotype of D. pectinata was reviewed by Billard (1907) and later by Cornelius (1979), and both concurred that this material is referable to Diphasia nigra ( Pallas, 1766) .

Cornelius (1979) proposed the earliest available name for this species: Diphasia margareta ( Hassall, 1841) . This proposition was followed virtually by all later authors but not by Cornelius (1995); he used the combination “ Diphasia pinaster sensu Hincks, 1868 ,” which is not recognized under provisions of the International Code of Zoological Nomenclature.

Finally, Schuchert (2012), for the sake of nomenclatural stability, proposed Diphasia margareta ( Hassall, 1841) as a valid name, considering Sertularia pinaster Ellis & Solander, 1786 as a questionable synonym of D. margareta ; we share his opinion.

The name Sertularia pinastrum Cuvier, 1830 was regarded as a new name for Sertularia pinaster Ellis & Solander, 1786 ( Cornelius 1979, 1995; Schuchert 2012); however, it in fact only represents an incorrect subsequent spelling of Sertularia pinaster (see Cuvier 1830: 301, footnote 5) and, therefore, it is not an available name.

Material examined. Western Sahara. CCLME-1110, stn BT205, 25º10´01"– 25º11´17"N, 14º51´53"– 14º52´07"W, 43–45 m, 27-XI-2011: three colonies 43–130 mm high, two with male gonothecae and one with female gonothecae. One colony 110 mm high with male gonothecae is the holotype ( MNCN 2.03/677); remaining colonies are paratypes ( MNCN 2.03/678; LZM-04473).

CCLME-1110, stn BT199, 24º52´21"–24º50´43"N, 14º58´20"–14º58´03"W, 30–31 m, 26-XI-2011: single colony 110 mm high, with male gonothecae; paratype (CFM-IEOMA-6215).

CCLME-1110, stn BT208, 25º49´42"–25º49´04"N, 15º27´28"–15º29´07"W, 350–355 m, 27-XI-2011: two colonies 80–120 mm high, with male gonothecae; paratypes (MNHN-IK- 2014-2197, LZM-02003).

CCLME-1110, stn BT213, 26º15´53"–26º14´42"N, 14º50´21"–14º51´30"W, 371– 363 m, 28-XI-2011: single colony 85 mm high, with male gonothecae; paratype (RMNH.COEL.42266).

Etymology. The specific name leonisae was chosen as a tribute to Mrs. Leonisa González, grandmother of the first author.

Biology. The material was collected from muddy bottoms. All fertile colonies were recorded in November.

Distribution. This species was recorded in only four localities off Western Sahara between 30 and 371 m.

Description. Hydrorhiza formed by a bundle of intertwining tubules adhering to soft sediments and supporting an erect and branched axis. Main axis monosiphonic, with sympodial growth and the subsidiary branches directed alternatively right and left, resulting in a scorpioid sympodium; thus, the main (or “false”) axis is composed of the basal parts of the successive branches (fig. 8A). Each branch originates from the preceding one and arises frontally between a pair of axial hydrothecae, starting at a short internode carrying a pair of hydrothecae. Rest of the branch composed of internodes of quite different lengths separated by transverse nodes more conspicuous in the distal part. The internodes support a variable number of hydrothecal pairs disposed strictly opposed in both the axis and branches.

The hydrocladia, inserted under a pair of hydrothecae, are long and pinnately arranged in the same plane as the “false axis” or branches. One and two pairs of axial hydrothecae between two successive hydrocladia, resulting in the separation of three pairs of hydrothecae between the hydrocladia on the same side (fig. 9B). In some colonies, we observed some hydrocladia oppositely arranged and arising under the same pair of hydrothecae. The hydrocladia composed of a succession of internodes of variable lengths separated by transverse nodes well marked distally. Hydrothecae disposed in sub-opposite pairs in the basal part, but strictly opposite in the distal part. Pairs of hydrothecae clearly separated vertically in the axis, branches and hydrocladia.

Hydrotheca tubular, adnate by 3/4 of its total length, curved outwards and narrowing towards the base. Free part of the adcauline wall short and almost straight. Abcauline wall with the perisarc slightly thickened at the level of the flexure but without any internal tooth or fold; distal portion of the abcauline wall slightly convex. Hydrothecal rim smooth with a semicircular aperture closed by a single and large flap attached to the adcauline sinus; aperture slightly tilted to the abcauline side (fig. 8B). Renovations are common and sometimes numerous, and the presence of a second operculum is also frequent (fig. 8C). Hydranths with 11–15 tentacles.

Female and male gonothecae occur in separate colonies and inserted perpendicularly on the frontal surface of the hydrocladia on a short pedicel under the base of a hydrotheca; female larger than male. Female gonotheca elongated, ovoid with four ribs running towards the base, and each one provided with two to four spines of variable morphology and length; additional spines developing between the ribs (fig. 8E–G). Inner apical part occupied by a well-developed marsupium communicated with the main gonothecal cavity by a circular aperture; two lateral funnels reach the gonothecal wall, forming a pair of lateral and opposite openings at the basal third of the gonothecae for larval release. Some empty gonothecae also showed an apical circular aperture, suggesting a second pathway for larval release.

Male gonothecae are triangular, widening from the base to the distal part (fig. 9D–H). The gonothecae are compressed laterally, with two distal spines, one at each corner. Some gonothecae showed a pair of distal spines at each corner, with sometimes a third spine in between. The apical border between the lateral spines presents five to 11 small cups, several of them provided with a circular aperture. An additional mesial spine located close to the distal border was sometimes observed on only one side of the gonothecae. The gonothecal cavity, filled with a mass of developing spermatocytes, was communicated with each cusp by fine canals.

Remarks. Diphasia leonisae n. sp. comes close to D. margareta on the basis of the morphology of the female gonothecae, with four external ridges carrying spines and a characteristic internal marsupium. Nevertheless, it differs from D. margareta and all related species on the basis of the morphology of the male gonotheca: triangular, laterally compressed and provided with several apical apertures along its distal border. Other differences with D. margareta are related to the habitus of the colony, which develops as a scorpioid sympodium; the hydrotheca is adnate over 3/4 of its total length and devoid of an internal ledge on the abcauline side; presence of supplementary spines on female gonothecae disposed between the external ridges.

The abcauline basal chamber observed under each hydrotheca is a feature shared with the other Diphasia species studied by us, but only observable in a strictly lateral view (fig. 9C).

Differences with the other species of the D. margareta group described in this report have been discussed below.

CCLME-1110 CCLME-1110 Stn BT213 Stn BT205

Figures

FIGURE 4. Diphasia margareta (Hassall, 1841). A–C, stn MO72; A, colony; B, part of hydrocladium; C, female gonotheca. D–E, stn MO78, male gonothecae. F, stn MUDR11, part of axis with insertions of hydrocladia.Scales:a, 2 cm; b–f, 0.5mm.

FIGURE 5. Diphasia margareta (Hassall, 1841). A–D, stn BS152; A, part of hydrocladium; B, female gonotheca; C–D, male gonothecae. Scales: a–d, 1 mm.

FIGURE 6. Diphasia margareta (Hassall, 1841). A–C, stn DE98; A, part of hydrocladium; B, female gonotheca; C, male gonotheca.D, Bergen Museum Nr.301, basal part of hydrocladium.Scales:a–d, 1 mm.

FIGURE 7. Diphasia margareta (Hassall, 1841). A–B, Bares, Spain; A–B, part of hydrocladium. C, stn SL–6, part of hydrocladium.Scales: a–c, 0.5 mm.