Plumularia contraria, Agís & Vervoort & Ramil, 2014

Agís, José Ansín, Vervoort, Willem & Ramil, Fran, 2014, Hydroids of the families Kirchenpaueriidae Stechow, 1921 and Plumulariidae McCrady, 1859 (Cnidaria, Hydrozoa) collected in the Western Pacific Ocean by various French Expeditions, Zoosystema 36 (4), pp. 789-840 : 800-813

Plumularia contraria n. sp.

( Figs 6 , 7 ; Table 6)

MATERIAL EXAMINED. — New Caledonia. MUSOR- STOM 4, stn CP 172, 19°01.2’S, 163°16.0’E, 275- 330 m, 17.IX.1985: one colony 83 mm height, without gonothecae, paratype ( RMNH 41612). — Stn CP 178, 18°56.3’S, 163°12.9’E, 520 m, 18.IX.1985: one spirally built colony 150 mm long, no gonothecae, holotype (MNHN-IK-2012-14253).

ETYMOLOGY. — The specific name contraria refers to the orientation of the hydrothecal aperture towards the hydrocladial axis, unusual in this genus.

DISTRIBUTION. — This species is known only from two localities in New Caledonia and was collected between 275 and 520 m depth.

DESCRIPTION

Colony examined without basal part. Stem branched and polysiphonic (with exception of apical part of colony), composed of one central primary tube bearing hydrocladia in distal part and surrounded by several auxiliary tubes, number of auxiliary tubes reduced towards distal parts. Only primary tube bearing apophyses and divided into internodes by transverse nodes only visible in apical zone of colony. Each internode with several apophyses (usually three in apical part) and three or four nematothecae, in one or two rows respectively, between two consecutive apophyses.

Branches spirally arranged, polysiphonic in older parts, and arising between apophyses and stem (axilar branched). The base of the branch also originates in its upper part a secondary tube directed towards the apical part of the colony that adheres to the main axis, which helps to maintain the polysiphonic structure. Basal part of branch with several nematothecae placed in two rows, rest of branch with apophyses alternately directed left and right, with two or four nematothecae between two consecutive apophyses. Each apophysis with a small mamelon on superior surface and three nematothecae: two in the axil and one unpaired above mamelon; a perisarcal ring at distal end.

Hydrocladia inserted on apophyses, arranged alternately left and right and slightly frontally. Hydrocladia composed of a succession of thecate internodes with oblique nodes. Each internode with one hydrotheca and four nematothecae: one mesial inferior, two lateral and one supracalycine. Hydrotheca deep, tubular, adcauline wall fully adnate, abcauline wall straight with distal part curved towards hydrocladium,with a well developed internal septum in the middle of its length inclined distally. Aperture of hydrotheca oriented to hydrocladial wall, nearly vertical; rim smooth with a slight elevation or undulation on the adcauline side.

The mesial inferior and suprahydrothecal nematothecae are placed on an elevation and lateral nematothecae inserted over small apophyses. All

A

SMIB 5

stn DW 101 Height of colony (in mm) 7 Stem internode, length 240-360 Diameter at node 30-70 First hydrocladial internode, length 100-140 Length thecate hydrocladial internodes 230-270 Length athecate hydrocladial internodes 200-240 Diameter at node 25-35 Hydrotheca Length abcauline wall 55-60 Length adcauline wall 60-70 Diameter at rim 65-70 Mesial nematotheca, length 45-50 Diameter at rim 20-25 Lateral nematotheca, length 60-70 Diameter at rim 25-30

nematothecae mobile, two-chambered and with adcauline wall of upper chamber deeply scooped.

In each hydrocladial internode are variable numbers of internal septa, between four and eight, in the apical and lower parts respectively.

Hydrocladia of stem differing from those of branches in starting with a short athecate internode bearing one nematotheca in the basal part, arising at an elevation, and with an internal septum in distal part. Nematotheca having same morphology as the others.

Gonothecae not observed.

REMARKS

Plumularia contraria n. sp. shows some similarities to P. elongata Billard, 1913 , in the morphology of the hydrothecae, in particular in its tubular form, in the presence of an intrathecal septum, and with the hydrothecal orifice oriented towards the hydrocladial axis. Nevertheless, both species clearly differ in the shape of the colony and the number of nematothecae on the thecate internodes. In P. contraria n. sp. the colony has a geniculate appearance with the lateral branches spirally arranged, whereas in P. elongata the ramifications are pinnate and always in the same plane, giving it a characteristic regular structure. Moreover, the apophyses and the hydrocladia are arranged latero-frontally in P. contraria n. sp. but in the same plane in P. elongata . In P. contraria n. sp. the suprahydrothecal nematotheca is a constant feature but it is always absent in P. elongata . There are also differences in the hydrothecal aperture: in P.contraria n. sp. the hydrothecal margin is straight and nearly parallel to the hydrocladial wall, whereas in P. elongata the margin is sinuous and depressed towards the adcauline side.

Plumularia cf. filicula Allman, 1877 ( Fig. 8 ; Table 7)

Plumularia filicula Allman, 1877: 29 , pl. 18, figs 1, 2. — Nutting 1900: 58, pl. 2 fig. 2. — Fraser 1944: 344, pl. 74 fig. 332. — Ramil & Vervoort 1992: 183, fig 47a-e.

Plumularia filicula – Hirohito 1983: 68, fig. 35; 1995: 275, fig. 94a (doubtful records).

Non Plumularia filicula – Vervoort & Watson 2003: 393, fig. 95C-F.

MATERIAL EXAMINED. — Norfolk Ridge. SMIB 5, stn DW 101, 23°21.2’S, 168°04.9’E, 270 m, 14.IX.1989, one colony with three plumes c. 7 mm high, no gonothecae ( MNHN).

DISTRIBUTION. — Plumularia filicula is a species with an amphi-Atlantic distribution, being reported from the Atlantic coast of the United States and from the Ibero-Moroccan Gulf ( Ramil & Vervoort 1992), between 146 and 1318 m. The records in the Pacific Ocean are considered dubious or excluded (see Remarks).

Our material was collected on the Norfolk Ridge at 270 m.

DESCRIPTION

Hydrorhiza tubular,adhering to substrate; hydrocauli monosiphonic, unbranched, divided into internodes by straight nodes, geniculate in younger parts. Cauline internodes all have a distal apophyses and one nematotheca in middle of opposite wall. Apophyses alternately directed left and right, with mamelon on superior surface and with two axillary nematothecae.

Hydrocladia with first internode having one nematotheca in the middle and a perisarc ring at each extremity.Rest of hydrocladium a succession of thecate and athecate internodes, separated by oblique nodes; thecate internodes with basal oblique and distal slightly oblique nodes, athecate internodes reverse. Each thecate internode with hydrotheca and three nematothecae: one mesial inferior and two lateral. Hydrotheca cup-shaped, widening towards margin, adcauline wall fully adnate, abcauline wall straight, aperture circular, slightly tilted downwards, rim smooth. Internal perisarc ring with varied development sometimes occurring at the extremes. All nematothecae bithalamic, movable and conical. Athecate internodes with two nematothecae, one in the lower half and the other in the upper half; one basal and one distal perisarcal ring of much varied development.

Gonothecae not observed.

VARIABILITY

Sometimes one athecate internode with a single nematotheca placed in the middle was observed; two consecutives internodes, each with only one nematotheca, may also occur.

REMARKS

The morphology of our colony agrees well with existing descriptions of this species. We found only minor differences in the length of hydrocladial internodes, hydrothecae and nematothecae, but the absence of gonothecae made an accurate identification not possible.

The colonies from Japan ( Hirohito 1983, 1995) are all devoid of gonothecae, and for this reason we consider the identification doubtful.

Nevertheless, the material described by Vervoort & Watson (2003) from New Zealand belongs, in our opinion, to a different species, because the morphology of gonotheca, provided with two nematothecae on the distal part, is quite different from those described by Allman (1877, type material) and by Ramil & Vervoort (1992, East Atlantic material). A similar opinion was expressed by Schuchert (2013b).

Plumularia habereri Stechow, 1909 ( Figs 9-13 ; Tables 8, 9)

Plumularia habereri Stechow, 1909: 77 , pl. VI, fig. 4; 1913: 91, figs 59, 60. — Ryland & Gibbons 1991: 532, fig. 5.

Plumularia habereri var. attenuata Billard, 1913: 42 , fig.34.

Plumularia habereri var. mucronata Billard, 1913: 46 , fig. 40, pl. II, fig. 24.

Not Plumularia habereri – Van Gemerden-Hoogeveen 1965: 60, figs 34-36 [record included in Denthitheca dendritica ( Nutting, 1900) ].

Dentitheca habereri – Hirohito 1995: 259, fig. 87a- e. — Stechow 1923a: 18; 1923b: 227. — Kirkendale & Calder 2003: 167.

Not Plumularia habereri – Schuchert 2003: 211, fig. 60 (record included in Plumularia elongata Billard, 1913 ). Not Dentitheca habereri – Di Camillo et al. 2010: 84, figs 2, 3, 5, 6 (record included in Plumularia elongata Billard, 1913 ).

MATERIAL EXAMINED. — Chesterfield Islands . CHAL- CAL 1 , stn DC 29, 19°30.60’S, 158°31.10’E, 100 m, 19.VII.1984: single large, broken colony and some fragments up to 140 mm ; no gonothecae ( MNHN) ( RMNH, three slides).

New Caledonia. LAGON, stn 0110bis, 22°23.8’S, 166°47.0’E, 40 m, 22.VIII.1984: four large colonies (one broken) c. 220 mm high, no gonothecae observed ( MNHN). — Stn 0114, 22°23.6’S, 166°49.6’E, 37 m, 22.VIII.1984: one colony c. 150 mm high and some fragments, without gonothecae ( MNHN). — Stn 0116, 22°25.2’S, 166°43.7’E, 43 m, 22.VIII.1984: single 130 mm high colony in two pieces ; no gonothecae ( MNHN) ( RMNH, two slides). — Stn 0127, 22°30.6’S, 166°45.9’E, 55 m, 23.VIII.1984: large flabellate colony 180 × 140 mm ; no gonothecae observed ( MNHN) ( RMNH, one slides).— Stn 0354, 22°32.0’S, 167°02.1’E, 78 m, 29.XI.1984: one fragmented colony c. 170 mm high ; no gonothecae ( MNHN). — Stn 0358, 22°31.4’S, 167°05.2’E, 50 m, 29.XI.1984: single colony 110 × 90 mm ; without gonothecae ( MNHN). — Stn 0373, 22°27.5’S, 167°10.5’E, 52-57 m, 21.I.1985: two colonies, 35-80 mm, and one fragment, no gonothecae ( MNHN). — Stn 0374, 22°30.2’S, 167°08.9’E, 70-72 m, 21.I.1985: single large colony (c. 300 × 300 mm) broken in several fragments ; no gonothecae observed ( MNHN) ( RMNH, one slides). — Stn 0379, 22°31.4’S, 167°10.8’E, 70 m, 21.I.1985: large colony c. 160 mm high and some fragments, no gonothecae ( MNHN) ( RMNH, two slides). — Stn 0387, 22°28.2’S, 167°13.4’E. 62- 65 m, 22.I.1985: two colonies, 115-150 mm high, without gonothecae ( MNHN). — Stn 0398, 22°37.0’S, 167°11.8’E, 71 m, 23.I.1985: forked, fan-shaped colony c. 80 × 120 mm ; no gonothecae ( MNHN) ( RMNH, two slides). — Stn 0426, 22°43.1’S, 167°19.9’E, 53 m, 25.I.1985: 120 mm high, forked stem and some fragments ; no gonothecae ( MNHN). — Stn 0477, 18°20.3’S, 163°05.5’E, 36 m, 28.II.1985: two large colonies and many fragments (c. 150 × 150 mm) ; no gonothecae observed ( MNHN). — Stn 0491, 18°56.0’S, 163°20.0’E, 450-460 m, 03.II.1985: c. 120 mm high colony ; no gonothecae ( MNHN).

Philippines. MUSORSTOM 3, stn DR 117, 12°31.2’- 12°31.3’N, 120°39.3’- 120°39.5’E, 92-97 m, 03. VI.1985: two broken colonies with many fragments up to 90 mm, no gonothecae ( MNHN).

New Caledonia. LAGON, stn 0600, 22°17.9’S, 167°04.4’E, 62-65 m, 05.VIII.1986: large branched colony (150 mm high) ; no gonothecae ( MNHN). — CHAL- CAL 2 , stn DW 80, 23°26.70’S, 168°01.80’E, 160 m, 31.X.1986: two branched colonies, 40-45 mm, without gonothecae. ( MNHN) ( RMNH, two slides) .

Coral Sea. CORAIL 2, stn CP 25, 20°25.00’S, 161°05.00’E, 70- 67 m, 22.VII.1988: several fragments, 86 mm high, one with three gonothecae (possibly immature) ( MNHN).

New Caledonia. Lagoon, Canal Woodin, 25-40 m, 13.IV.1995. Leg.Dr Richer de Forges Noumea. Coelenterate 27624: large colony 240 mm, without gonothecae. ( MNHN)

ADDITIONAL MATERIAL. — Type material of Plumularia habereri Stechow, 1909 : ZSM 20041623 . Sagami Bay , V-1901, one slide ; ZSM 20041622 , ZSM 20041625 , ZSM 20051002 . Between Ito and Hatsu-Shima Island, depth 150 m, III-1903, three slides .

Syntype material of Plumularia habereri var. attenuata Billard, 1911 : Siboga Expedition. Stn 144: MNHN H.L. 1267, one slide.

Syntype material of Plumularia habereri var. mucronata Billard, 1911 : Siboga Expedition. Stn 80: MNHN H.L. 1272, one slide.

DISTRIBUTION. — P. habereri is known from Japan ( Stechow 1909, 1913, 1923b), Indonesia ( Billard 1913), Fiji ( Ryland & Gibbons 1991) and Guam ( Kirkendale & Calder 2003). Their presence in Tulear, Madagascar ( Di Camillo et al. 2010: Table 1) must be confirmed. The depth range varies between 17 and 150 m.

Our material comes from Philippines, Coral Sea, Chesterfield Island and New Caledonia, and was collected between 25 and 460 m depth, extending their bathymetrical distribution to the upper bathyal.

DESCRIPTION

Hydrorhiza composed of stolonial fibres mixed with sediment from which emerges one polysiphonic and branched axis; branches arising laterally from secondary tubes.

Stem divided into internodes by straight nodes visible only in distal part of stem and branches; each internode with several apophyses. Nematothecae placed in secondary tubules. Apophyses with a well developed mamelon on superior surface and three nematothecae: two axillary and one over mamelon slightly displaced laterally.

Hydrocladia inserted on apophyses, alternately directed left and right on stem and branches. Hydrocladia formed by a succession of thecate internodes separated by oblique nodes that may not be visible in the first internodes.

Each hydrocladial internode with one hydrotheca and three nematothecae: one mesial inferior above a well developed elevation and two laterals. Hydrotheca cup-shaped, more or less deep, adcauline wall straight and fully adnate, abcauline wall straight, rim smooth and with adcauline side curved down. Mesial inferior and lateral nematothecae with adcauline wall of superior chamber deeply scooped. All nematothecae movable, two chambered and conical. In each internode at least two internal thickenings located near the basal and distal ends, in some internodes six perisarcal rings have been observed: two under, three behind and one above the hydrotheca.

Gonothecae, perhaps not fully developed, inserted on apophyses, pear-shaped and with distal end truncated.

REMARKS

Plumularia habereri was described by Stechow (1909) from two samples collected in Sagami Bay ( Japan), in May of 1901 (flask without number) and March of 1903 (Locality Nr 4781, between Ito and Hatsushima Island) ( Stechow 1909: 78). Later Billard (1913), using the material collected by the Siboga Expedition, described five varieties inside P. habereri : P. habereri var. attenuata , P. habereri var. elongata , P. habereri var. subarmata Billard, 1913 , P. habereri var. mediolineata Billard, 1913 and P.habereri var. mucronata . Plumularia habereri var. attenuata coincides with the material described by Stechow (1909) as P.habereri ; P.habereri var. elongata is clearly distinct, especially in the morphology of the hydrothecae; the rest of the varieties display some variations that in our opinion can be assigned to one of these two forms.

Schuchert (2003) indicates that most of these forms are quite different from that described from the type locality, but includes all of them under the binomen P.habereri since they can not be considered as subspecies because of their sympatric origins. Nevertheless he indicates that some of these varieties, and especially P. habereri var. mediolineata to which his material corresponds, might represent different species.

As part of this work we reviewed some of the type material of P. habereri from the two localities reported by Stechow (1909), deposited in the Zoologische Staatssammlung München ( ZSM 20041622, 20041623, 20041625, 20051002) (Rutensteiner et al. 2008: 20), as well as the syntypes of all varieties described by Billard (1913), deposited in the MNHN ( Van Praët 1979: 923, 924). We conclude that two different species are represented: Plumularia habereri Stechow 1909 and Plumularia elongata Billard 1913 (described as P. habereri var. elongata Billard, 1913 ). In Van Praët’s paper, P. habereri var. mucronata was not included, but the syntype of it is also in collections of MNHN ( MNHN H.L. 1272).

Plumularia habereri is distinguished by the morphology of its hydrothecae, having the abcauline wall straight, the opening directed upwards, and with the hydrothecal margin straight and perpendicular to the hydrocladial axis but cut obliquely downwards in the adcauline side. In both the oldest parts of the colony of this species and in the youngest or juvenile parts, the morphology of the hydrothecae does not vary. Moreover, in neither the type material nor in numerous colonies examined from the Philippines, the Coral Sea, and the New Caledonia region, have we observed the characters of P. elongata . These include curvature of the abcauline wall, inclination of hydrothecal rim towards the hydrocladia, and presence of an intrathecal septum (see below).

Plumularia habereri var. mucronata , whose distinguishing features are the greater development of the projection on which the mesial inferior nematotheca is placed and disposition of lateral nematothecae on small domes ( Billard 1913), is included here in P. habereri . Examination of the syntype reveals that while the mesial inferior projection is more developed than in material identified as P. habereri var. attenuata , this character is similar to that observed in type material of the P. habereri . Moreover, we have not observed the existence of the small lateral domes described by Billard (1913), and insertion of the lateral nematothecae are, in all aspects, similar to the rest of the studied material.

The descriptions and figures of Ryland & Gibbons (1991) and Hirohito (1995 as Dentitheca habereri ) closely correspond with this species. We also consider valid the record of Kirkendale & Calder (2003 as Dentitheca habereri ) because they indicate that their material is identical to hydroids described by Stechow (1909) and Hirohito (1995).

Plumularia habereri var. mediolineata , P. habereri var. subarmata and the records of P. habereri of Schuchert (2003) and Di Camillo et al. (2010) belong to P.elongata (see below). Records of this species from the Caribbean (Van Gemerden-Hoogeveen 1965, Flórez González 1983, Bandel & Wedler 1987) were included in Dentitheca dendritica ( Nutting 1900) by Calder & Kirkendale (2005) and we agree. Dentitheca dendritica comes close to P.habereri , but, like Calder (2013), we hesitate in synonymizing the two. Their wide geographic separation makes a comparative study necessary before reaching a final conclusion. Regarding referral of this species to Plumularia or Dentitheca (Stechow, 1919) , a matter of discussion in recent years, review of the type material of Dentitheca hertwigi ( Stechow, 1909) (see below), type species of the genus ( Stechow 1923b, Millard 1975), has convinced us, in agreement with Schuchert (2003) and Bouillon et al. (2006), that it must be placed in Plumularia because it lacks the two large triangular lobes characteristic of Dentitheca .

Figures

FIG. 6. — Plumularia contraria n. sp., MUSORSTOM 4; A, stn CP 172 (paratype),colony; B-E, stn CP 178 (holotype):B, C, internodes, frontal view;D, first internode of hydrocladia,lateral view;E, last internode of hydrocladia,lateral view.Scale bars:A,1 cm;B-E,0.1 mm.

FIG. 7. — Plumularia contraria n. sp., MUSORSTOM 4; A, B, stn CP 178 (holotype): A, basal internodes, lateral view; B, apophyse and first internode; C, stn CP 172 (paratype), branch. Scale bars: 0.1 mm.

FIG. 8. — Plumularia cf. filicula Allman, 1877, SMIB 5, stn DW 101: A, colony; B, hydrocladia with first athecate internode without nematotheca, lateral view; C, two consecutives athecate internodes on distal part of hydrocladia, each one with one nematothecae; D, apical part of hydrocladia, frontal view; E, internode of stem with hydrocladia, lateral view. Scale bars: A, 1 mm; B-E, 0.1 mm.

FIG. 9. — Plumularia habereri Stechow, 1909: A, LAGON, stn 0373, colony; B-E, CHALCAL 1, stn DC 29; B, detail of branch; C, internode with renovations after damaged; D, internode, frontal view; E, basal internodes of hydrocladia, lateral view. Scale bars: A, 1 cm; B-E, 0.1 mm.

FIG. 10.— Plumularia habereri Stechow,1909,A, B, LAGON,stn 0127:A, internodes,lateral view; B, internode from half of hydrocladia, lateral view; C-E, LAGON,stn 0116:C, internode from distal part of hydrocladia,lateral view; D, internode in frontal view; E, internode, lateral view; F, G, CORAIL 2, stn CP 25, gonothecae. Scale bars: 0.1 mm.

FIG. 11. — Plumularia habereri Stechow, 1909, type material: A-C, ZSM 20041622: A, basal internodes of hydrocladia, lateral view; B, internode, frontal view;C, internode from middle of hydrocladia,lateral view;D-E, ZSM 20041623:D, first internodes of hydrocladia, lateral view; E, distal internodes of hydrocladia, lateral view. Scale bars: 0.1 mm.

FIG. 12. — Plumularia habereri Stechow, 1909, syntype of Plumularia habereri var. attenuata Billard, 1913; SIBOGA EXPEDITION, stn 144, MNHN H.L. 1267: A, first internodes of hydrocladia, lateral view; B, internode, frontal view. Scale bars: 0.1 mm.

FIG. 13.— Plumularia habereri Stechow,1909,syntype of Plumularia habereri var.mucronata Billard,1913;SIBOGA EXPEDITION,stn 80, MNHN H.L. 1272, internodes, lateral view. Scale bar: 0.1 mm.