Egmundella humilis Fraser, 1936

Galea, Horia R., 2013, New additions to the shallow-water hydroids (Cnidaria: Hydrozoa) of the French Lesser Antilles: Martinique, Zootaxa 3686 (1), pp. 1-50 : 13

Egmundella humilis Fraser, 1936

( Fig. 3 H, I; Table 2 )

Egmundella humilis Fraser, 1936: 50 , pl. 1 fig. 2.― Hirohito, 1995: 84, fig. 24A–C.? Lovenella sp. Millard & Bouillon, 1973: 42, fig. 5E, F.

? Egmundella modesta Millard & Bouillon, 1975: 5 , fig.1E–H.― Vervoort, 2006: 224, figs 7.3, 8.3, 9D–H.

Material examined. Stn. 6, 18.i.2012, 15– 18 m, M007: small, sterile colony on stolon of Clytia gracilis (M. Sars, 1850) . Stn. 14, 20.ii.2012, 10– 13 m, M231: minute, sterile colony on stolon of Hincksella formosa ( Fewkes, 1881) .

Description. Small, stolonal colonies composed of hydrothecae borne singly on top of basally wrinkled pedicels of varied length. Hydrothecae tubular, walls smooth, rounded basally and provided with a thin diaphragm; a belt of desmocytes above; operculum composed of an indeterminable number of interconnected triangular flaps delimited from the rim by crease line. Nematothecae exclusively stolonal, ovoid to globular, with small, rounded, distal aperture; lumen filled with several large, banana-shaped nematocysts.

Remarks. When Millard & Bouillon (1975) described Egmundella modesta from the Seychelles, they did not compare their new species with E. humilis Fraser, 1936 , described earlier from Japan. Conversely, the latter nominal species was redescribed by Hirohito (1995), who also discovered its gonosome, though he did not discuss its affinities with E. modesta . Vervoort (2006), too, did not comment on the relationship between his Mauritanian hydroid assigned to E. modesta and Fraser's species.

From the available accounts of the two nominal species, it is obvious that their trophosomes are indistinguishable morphologically, and that their dimensions fall within a common range of variation ( Table 2 ).

Present study Fraser (1936) Millard & Bouillon (1973), Millard & Vervoort

as? Lovenella sp. Bouillon (1975), (2006),

Praslin Mahé as E. modesta as E. modesta

Pedicel

I assign the present material to Fraser’s species, which would have priority if proven conspecific with E. modesta , but this assignment is tentative given that the gonosome of E. modesta is unknown.

Another species occurring in the Caribbean is E. superba Stechow, 1921 , but it has much taller pedicels, while its hydro- and nematothecae are two times bigger ( Stechow 1921, Calder 1991).

Geographical distribution. Japan ( Fraser 1936, Hirohito 1995), the Seychelles ( Millard & Bouillon 1975, as E. modesta ), Mauritania ( Vervoort 2006), Martinique (present study).

Figures

FIGURE 3. A, B: Clytia hemisphaerica (Linnaeus, 1767) ― hydro- (A) and gonotheca (B). C, D: Clytia noliformis (McCrady, 1859) ― hydro- (C) and gonotheca (D). E:? Gastroblasta sp. ― hydrotheca. F, G: Orthopyxis sargassicola (Nutting, 1915) ― hydro- (F) and gonotheca (G). H, I: Egmundella humilis Fraser, 1936 ― hydro- and nematothecae from samples M 231 (H) and M 007 (I). J – P: Relative sizes of the hydrothecae of the hebellids discussed in the text. J, Q, R: Anthohebella communis (Calder, 1991) ― hydrothecae (J, Q) and gonotheca with medusoid gonophore (R). K, S, T: Hebella dyssymetra Billard, 1933 ― hydrothecae. L, U – Y: Hebella scandens (Bale, 1888) ― hydrothecae (L, U); gonotheca seen laterally (V) and apically (X), showing the four-flapped operculum; gonophore (Y). M, Z: Hebella sp. 1 ― hydrotheca. N: Hebella sp. 2 ― hydrotheca. O: Hebella sp. 3 ― hydrotheca. P: Hebella sp. 4 ― hydrotheca. Scale bars: 200 µm (H, I, Z), 300 µm (A – E, S, T), 500 µm (Q, R, U – Y), 1 mm (F, G, J – P).

Tables

TABLE 2. Measurements of Egmundella humilis Fraser, 1936 (in µm).

- length	75–240	<400	70–320	20–220	140–710	184–252
- diameter at base	40–55	–	–	–	30–50	73–78
Hydrotheca
- length	120–305	<400	230–270	140–200	200–330	364–409