Taxonomy and diversity of Hydrozoa (Cnidaria, Medusozoa) of La Paz Bay, Gulf of California
Author
Mendoza-Becerril, María A.
CONACYT-Centro de Investigaciones Biológicas del Noroeste S. C., Inst. Politécnico Nacional 195, La Paz, BCS 23096, México. m _ angelesmb @ hotmail. com; https: // orcid. org / 0000 - 0002 - 9449 - 0543
Author
Estrada-González, Mariae C.
Universidad Autónoma de Baja California Sur, Carretera al Sur km 5.5, La Paz, BCS 23080, México.
Author
Mazariegos-Villarreal, Alejandra
Centro de Investigaciones Biológicas del Noroeste S. C., Inst. Politécnico Nacional 195, La Paz, BCS 23096, México. amaza 04 @ cibnor. mx; https: // orcid. org / 0000 - 0001 - 8932 - 0462
Author
Restrepo-Avendaño, Luisa
Grupo de Investigación en Limnología Básica y Experimental y Biología y Taxonomía Marina (LimnoBasE y Biotamar), Instituto de Biología, Universidad de Antioquia, Apartado 1226, Medellín, 05001000, Colombia.
Author
Villar-Beltrán, Rogelio D.
Facultad de Ciencias Biológicas y Agropecuarias, Campus Tuxpan, km 7.5 Carretera Tuxpan-Tampico, Tuxpan, Veracruz 92850, México. biolm. rogelio. villar @ gmail. com; https: // orcid. org / 0000 - 0001 - 5459 - 9715
Author
Agüero, José
Medusozoa México, La Paz, BCS 23060, México. j _ zans @ yahoo. com; https: // orcid. org / 0000 - 0003 - 2565 - 0256
Author
Cunha, Amanda F.
Departamento de Zoologia, Instituto de Biociências, Universidade de São Paulo (USP), Rua do Matão, Travessa 14, 101, São Paulo 05508 - 090, Brazil. amanfcunha @ gmail. com; https: // orcid. org / 0000 - 0003 - 3276 - 2651
text
Zootaxa
2020
2020-07-01
4808
1
1
37
journal article
10.11646/zootaxa.4808.1.1
1175-5326
3927861
64E656F6-FBD7-4BA2-B399-B10A97CBEF72
Clytia linearis
(
Thornely, 1900
)
Figs. 8
A–H
Obelia linearis
Thornely 1900: 453
, pl. 44, fig. 6.
Clytia acutidentata
Fraser 1938a: 28
, pl. 7, fig. 29.—
Fraser 1938b: 109
.—
Fraser 1948: 206
.
Gonothyraea serialis
Fraser 1938a: 35
, pl. 8, fig. 37.—
Fraser 1938c: 133
.—
Fraser 1948: 212
.
?
Clytia striata
.—
Álvarez-Léon & Wedler 1982: 27
, figs.
2g
, 5e [not
Clytia striata
(
Clarke, 1907
)
].
Clytia linearis
.—
Calder 1996: 258
, fig. 2.—
Humara-Gil & Cruz-Gómez 2018: 458
, fig. 3.
Type
locality.
Papua New Guinea
:
Blanche Bay
,
New Britain
(
Thornely 1900
)
.
Material examined.
Medusa—PB7_1b, sampling site 1 (2), mature, females 27°C; PB7_20, sampling site 2 (2), mature, one female and one male, 27°C. Polyp—PB7_27, sampling site 1 (1), mature, 27°C, on cirripeds; PB7_ 32, sampling site 2 (1), immature, 27°C, on
Sargassum
; PB7_38, sampling site 3 (1), immature, 26.5°C, on alga.
Description.
Medusa—Umbrella slightly flattened, hemispherical (
1.5–2.3 mm
wide,
0.5–1.6 mm
high), with narrow velum. Manubrium short and quadrangular (
0.3 mm
long,
0.3–0.9 mm
wide), without peduncle, mouth with four simple lips. Circular canal and four radial canals narrow. Gonads oval (
0.1–0.6 mm
long), with median groove and without peduncle, located on the middle of radial canals in small specimens or on the distal portion of radial canals in large specimens. Eight to 16 hollow marginal tentacles, each associated with a tentacle bulb. Eight to 15 ectodermal closed statocysts, each with one statolith, alternating with tentacle bulbs.
Polyp—Colonies erect, sympodial, occasionally branching. Erect stems up to
12 mm
high, monosiphonic, arising from a creeping hydrorhiza. Internodes 768.4 μm long, slightly curved, each with 4–7 annulations at the base; pedicel with distal hydrotheca. Internodes with upward curved apophysis, adjacent to hydrothecal pedicel, given off the next internode in alternate directions. Pedicels 439.0 μm long, with 5–16 annulations along its whole length. Hydrotheca cylindrical, 822.8 μm long, 476.3 μm wide at margin, 154.6 μm wide at diaphragm, with thin perisarc. Margin with 12–15 acute triangular cusps, often folded inwards, with pleats extending from the tips of the cusps downwards to the upper part of the hydrothecal wall. Hydrothecal diaphragm thin, transverse. Gonotheca cylindrical, smooth, arising from the base of hydrothecal pedicels. Gonothecae pedicels short, with 3–4 annulations. Gonotheca 918.5 μm long, 417.4 μm in maximum diameter, with a small constriction near the aperture (297.3 μm wide), and truncated on top. Up to eight young medusae inside the gonothecae.
Nematocysts (length x diam.). Medusa—Microbasic b-mastigophore
type
A (7.9–9.1 x
1.6–2.1 µm
). Polyp—Mi-crobasic b-mastigophore
type
A (4.9–6.5 x
1.7–2.2 µm
), microbasic b-mastigophore
type
B (8.7–9.8 x
2.5–3.04 µm
).
More detailed description in
Calder (1991a)
and
Lindner & Migotto (2002)
.
Taxonomic status.
Accepted. AphiaID 117370.
Remarks.
Clytia striata
(
Clarke, 1907
)
was included in the synonym of
C. linearis
(Thorneley, 1900)
by
Calder (1991a)
, as well as
Clytia acutidentata
Fraser, 1938a
and
Gonothyraea serialis
Fraser, 1938b
from the northeastern Pacific (
Calder 1991a
;
Calder
et al.
2009
). However, the shape of the hydrothecal cusps and the fact that
C. striata
have been frequently reported in association with pteropods (
Clarke 1907
;
Vervoort 1946
) suggest they might be different species. The description and figure of
C. striata
from
Álvarez-León & Wedler (1982)
closely agrees with
C. linearis
(Thorneley, 1900)
, but as the status of
Clytia striata
(
Clarke, 1907
)
is still not clear, a more detailed study is needed to confirm its identification. Specimens of
C. linearis
recorded by
Humara-Gil & Cruz-Gómez (2018)
are smaller in size (colonies
1.4–2.3 mm
high and hydrothecae
270 µm
long) when compared with our specimens and descriptions from the literature (colonies up to
21.5 mm
high and hydrothecae
500–1200 µm
long) (
Calder 1991a
;
Lindner & Migotto 2002
; current study). Although their description could be based on early stages of development (
Humara-Gil & Cruz-Gómez 2018
), it is also possible that their record represents a different species, but this hypothesis needs to be further investigated.
The diameter of the umbrella, the number of tentacles, and the position of the gonads varied among our medusae specimens, suggesting they represent different stages of development. Considering these variations, as well as the shape of the gonads, they agree with the description of
C. linearis
(Thorneley, 1900)
of
Lindner & Migotto (2002)
. However, it is important to acknowledge that the medusae of
Clytia
Lamouroux, 1812
are usually challenging to identify due to the paucity of diagnostic characters that frequently overlap among different species, as a result of their ontogenetic variation. Therefore, we stress the importance of additional life cycle studies with species of
Clytia
to uncover potential morphological and genetic variation of their medusa stage, contributing to species delimitation.
Distribution.
Species widely distributed in warm waters of all oceans, occasionally occurring in temperate waters (
Calder 1991a
;
Lindner & Migotto 2002
). In Mexican Pacific, only the polyp phase was reported for the coasts of Baja California (
Isla
Partida) (
Fraser 1938b
), Baja California Sur (Rocas Alijos) (
Calder 1996
), Sinaloa (Mazatlán) (
Álvarez-León & Wedler 1982
), Jalisco (Tenacatita Bay) (
Fraser 1938c
), Colima (Socorro Island) (
Fraser 1948
), Guerrero (White Friars Islands) (
Fraser 1938a
), and Oaxaca (Corralero Bay and Santa Cruz Bay) (
Humara-Gil & Cruz-Gómez 2018
).