Symplectoscyphus semper Galea & Schories

Galea, Horia R., Schories, Dirk, Försterra, Günter & Häussermann, Verena, 2014, New species and new records of hydroids (Cnidaria: Hydrozoa) from Chile, Zootaxa 3852 (1), pp. 1-50 : 36-37

Symplectoscyphus semper Galea & Schories , sp. nov.

(Plate 3C; Fig. 7G–J; Table 9)

Material examined. Taltal, lat. -25.38333, long. -70.51667, 24.iv.2012, 26 m, sample 07: a colony composed of numerous broken stems and cladia, fragments up to 3 cm high, some bearing gonothecae (holotype: MHNG-INVE- 86229).

Description. Colony fragmentary, very brittle, seems to have had originally a coplanar appearance (Pl. 3C). Less damaged stems monosiphonic, with occasionally a few basal constrictions above origin from stolon, followed by a smooth, straight portion devoid of hydrothecae. Remainder of stem divided into geniculate internodes delimited by rather weak constrictions of the perisarc. Each internode, usually with two alternating hydrothecae, a lateral apophysis opposite to the distal hydrotheca, as well as an axillar hydrotheca (Fig. 7G1). Cladia regularly alternate, borne of stem apophyses and delimited basally from stem by transverse nodes. Cladia straight, occasionally divided into internodes (Fig. 7G2); up to second order branches arising irregularly. Internodes of stem 510−625 µm long, those of cladia 460−535 µm long. Hydrothecae alternate on stem and branches, more approximate on the latter. Hydrotheca tubular, less than half adnate (free adaxial side 205−235 µm, adnate part 335−380 µm), conspicuously bent outwards and slightly upwards (Fig. 7H); abcauline wall concave, 290−315 µm long; base of hydrotheca 170−195 µm wide, and 215−225 µm wide at aperture. Gonothecae, presumably female, nearly tubular, tapering below, provided with 10−12 deep, transverse, independent ridges directed upwards; distalmost ridge either hidden by the rather well-developed, precedent one (Fig. 7I), or more or less exposed (Fig. 7J); total length 1815−1975 µm, and 640−705 µm wide in middle. A terminal plateau gives rise to a moderately long funnel (210−230 µm), widening gradually from base (150−160 µm wide) towards the distal aperture (210−225 µm wide).

Remarks. A thorough study of the relevant literature showed that no other species of the genus possesses such tubular gonothecae, with well-developed transverse ridges, whose free parts are almost adpressed to the thecal wall. This species somewhat recalls the widely-spread S. filiformis ( Allman, 1888) , but its hydrothecae are bigger in comparison and more approximated, and its gonothecae are almost two times longer. A tabulated list of all symplectoscyphids provided with transversely ridged (not spirally grooved) gonothecae is given in Table 9.

Etymology. From the Latin semper , meaning continuous, making reference to the constant rate of discovery of new species belonging to this widely speciose genus.

Distribution in Chile. Taltal (present study).

World records. Only known from Chile.