Monostaechas quadridens ( McCrady, 1859 )

Agís, José Ansín, Vervoort, Willem & Ramil, Fran, 2009, Hydroids of the family Halopterididae (Cnidaria, Hydrozoa) collected in the western Pacific by various French expeditions, Zoosystema 31 (1), pp. 33-61 : 53-54

Monostaechas quadridens ( McCrady, 1859) ( Fig. 9 ; Table 9)

Plumularia quadridens McCrady, 1859: 199 .

Monostaechas dichotoma Allman, 1877: 37 , pl. XXII, figs 1-5.

Monostaechas quadridens – Nutting 1900: 75, pl. XIII, figs 1-4. — Mammen 1967: 302, figs 98, 99. — Vervoort 1968: 61, 108, fig. 28a, b. — Millard 1975: 365, fig. 117D-F. — Calder 1983: 17, fig. 9. — Hirohito 1995: 249, fig. 84a-g. — Migotto 1996: 50, fig. 9i. — Schuchert 1997: 130, fig. 47a-e. — Ansín Agís et al. 2001: 171, fig. 7a-e. — Vervoort & Watson 2003: 364, fig. 88H-J.

Monostaechas fisheri f. simplex Billard, 1913: 16, text-fig. 7, pl. 1, fig. 10.

Monostaechas quadridens f. stechowi Leloup, 1935: 2, figs 2, 3.

Antennella diaphana diaphana Van Gemerden-Hoogeveen 1965: 49 [not Halopteris diaphana (Heller, 1868) ].

MATERIAL EXAMINED. — Chesterfield Islands. CHAL- CAL 1, stn CP 12, 20°34.30’S, 158°47.40’E, 67 m, 23.VII.1984, 1 fragment found between Macrorhynchia phoenica ( Busk, 1852) , no gonothecae ( MNHN). — Stn DC 39, 20°28.90’S, 158°48.70’E, 40 m, 23.VII.1984, several small stems, no gonothecae ( MNHN).

Philippines. MUSORSTOM 3, stn DR 117, 12°31.2’N, 120°39.3’E, 92-97 m, 3. VI.1985, 1 colony and some fragments, no gonothecae ( MNHN). — Stn CP 131, 11°36.6’N, 121°43.10’E, 111-113 m, 5. VI.1985, 2 mutilated stems c. 15 mm high, with male and female gonothecae ( MNHN).

New Caledonia. BIOCAL 1, stn CP 108, 22°02.522’- 22°02.735’S, 167°05.680’- 167°06.050’E, 335 m, 9.IX.1985, many colonies some with gonothecae ( MNHN). — Stn CP 110, 22°12.383’- 22°13.315’S, 167°06.434’- 167°09.936’E, 275-320 m, 9.IX.1985, 1 colony and 2 fragments, with male gonothecae and also 1 damaged female gonotheca ( MNHN).

CHALCAL 2, stn DW 76, 23°40.50’S, 167°45.20’E, 470 m, 30.X.1986, 1 colony with 3 stems on sponge, no gonothecae ( MNHN).

Norfolk Ridge. SMIB 4, stn DW 44, 24°56.0’- 24°46.5’S, 168°08.2’- 168°08.2’E, 270-300 m, 8.III.1989, bunch of c. 10 stems, some with a few hydrocladia, no gonothecae ( MNHN). — Stn DW 55, 23°21.4’- 23°21.4’S, 168°04.5’- 168°04.8’E, 215-260 m, 9.III.1989, many colonies on sponge and many fragments, with male and damaged female gonothecae ( MNHN). — Stn DW 56, 23°20.6’- 23°21.1’S, 168°05.2’- 168°04.7’E, 230-260 m, 9.III. 1989, 20 mm high colonies on worm tube, no gonothecae ( MNHN). — Stn DW 57, 23°21.5’- 23°21.0’S, 168°04.6’- 168°04.5’E, 210-260 m, 9.III.1989, 1 colony on Eudendrium sp. and 2 fragments, no gonothecae ( MNHN).

SMIB 5, stn DW 76, 23°41.2’S, 168°00.5’E, 280 m, 7.IX.1989, small fragment and 1 hydrocladia, no gonothecae ( MNHN). — Stn DW 95, 22°59.7’S, 168°19.8’E, 200 m, 14.IX.1989, several stems c. 20 mm high, with damaged gonothecae ( MNHN). — Stn DW 101, 23°21.2’S, 168°04.9’E, 270 m, 14.IX.1989, 2 fragments with male gonothecae ( MNHN).

DISTRIBUTION. — Monostaechas quadridens is widely distributed in tropical, subtropical and temperate waters of the great oceans ( Rees & Thursfield 1965; Schuchert 1997).

Our material was collected at Chesterfield Islands, Philippines, New Caledonia and Norfolk Ridge, between 40 and 470 m depth.

VARIABILITY

The material of SMIB 4, stn DW 44, DW 55, DW 56 and BIOCAL 1, stn CP 108 shows the axillar nematothecae displaced laterally towards left or right in the same hydrocladium ( Fig. 9B ).

Three internodes (one from material collected at CHALCAL 2, stn DW 76 and two at SMIB 4, stn DW 55) have two axillar nematothecae behind the adcauline hydrothecal wall; each of these axillar nematothecae is separately inserted on the internode and placed laterally.

REMARKS

In spite of the variations observed, the material examined has been included in Monostaechas quadridens because it agrees in morphology with that species: the branching pattern is a helicoid sympodium, the hydrothecae are cup-shaped and there is usually one axillar nematotheca.

Figures

FIG. 9.— Monostaechas quadridens (McCrady,1859):A, B, SMIB 4,stn DW 55,internodes;A, lateral view;B, frontal view;C, D, BIOCAL 1, stn CP 110, internodes with differently developed lateral nematothecae, lateral views. Scale bars: A, B, 0.1 mm; C, D, 0.2 mm.