Setosabatieria triangularis, Riera, Rodrigo, Núñez, Jorge & Brito, María Del Carmen, 2006

Riera, Rodrigo, Núñez, Jorge & Brito, María Del Carmen, 2006, Two new species of Comesomatidae Filipjev, 1922 (Nematoda: Chromadorida) from sandy bottoms of Tenerife, Canary Islands, Zootaxa 1126, pp. 53-61 : 58-60

Setosabatieria triangularis sp. nov.

( Figure 3 , Table 2 )

Type locality. Los Cristianos beach (Tenerife, Canary Islands).

Type material. Holotype. Adult male 1.7 mm long, mounted on a slide (coordinates 28º02´58´´N / 16º42´54´´W; 3 m depth) [TFMCBMNA/00011]. Collected by R. Riera, November 2000. Allotype, adult female, 2.1 mm long, mounted on a slide (coordinates 28º02´58´´N / 16º42´54´´W; 3 m depth) [DBAULL NE/TC1S11]. Collected by R. Riera, May 2000.

Paratypes. Adult male, 2.4 mm long, mounted on a slide (coordinates 28º02´58´´N / 16º42´54´´W; 3 m depth) [DBAULL NE/TC7S11]. Collected by R. Riera, November 2000. Collected by R. Riera, May 2000. Adult female, 1.6 mm long, mounted on a slide (coordinates 28º02´58´´N / 16º42´54´´W; 3 m depth) [DBAULL NE/TC7S12]. Collected by R. Riera, November 2000.

Meristic data. Cristianos subtidal: May, 1 female (Allotype), November, 1 female (f2), 2 males (Holotype and m2).

Etymology. The specific name refers to the triangular gubernaculum of this species.

Description.

Male: Body slender, attenuating towards both ends. Head round and slightly set off. Cuticle with very fine transverse striations, sometimes inconspicuous in the posterior half. Amphids are 68% of the corresponding body diameter in width, consisting of 2.5 turns, located at 6 m from the anterior end. Buccal cavity conical and small, without noticeable teeth. Inner labial setae lacking. Six outer labial setae 2 m long and 4 cephalic setae 1.6 cephalic diameters long, situated on the anterior part of the head. Subcephalic setae 13 m long, numerous, arranged in 6–9 rows and located at 21–60 m from the anterior end. Pharynx narrow and cylindrical. Ventral gland and nerve ring not seen.

The reproductive system is diorchic, with two opposed testes, almost inconspicuous. Spicules 1.7 anal diameters long, paired, arcuated and without marked capitulum. Gubernaculum 0.75 anal diameters long, with slender apophysis and distally compressed. 15 precloacal supplements 3 m wide, the posteriormost located at 21 m from the cloaca. Precloacal seta 7 m long, situated at 18 m from the cloaca. Tail 5.3 anal diameters long, cylindrical and with slightly swollen posterior tip. Subterminal setae 17 m long, located at 5 m from the posterior end. Caudal setae 25 m long. Spinneret conspicuous.

Female: They are similar to males. Tail length slightly shorter than in males (3.2–4.5 anal diameters). The reproductive system is didelphic, with two opposed and reflexed ovaries. Vulva located in the anterior half of the body, at the level of 45.7% of the total body length.

Discussion. Setosabatieria triangularis new species most closely resembles S. fibulata (Wieser, 1954) in the shape of copulatory apparatus, but S. triangularis new species differs in having amphids 2.5 turns, occupying 68% of the corresponding body diameter, while S. fibulata possess more developed amphids (90% cbd), with 4.25 turns. S. triangularis new species can be distinguished from the remaining species of the genus: S. hilarula (De Man, 1922) and S. jingjingae ( Guo & Warwick, 2001) in the number of amphid turns (3.25 in S.

hilarula and 3.5 in S. jingjingae ) and the size of the gubernaculum, very slender with a triangular apophysis in S. triangularis new species but narrower and slender in S. hilarula and S. jingjingae .

Ecology. This species was recorded in Los Cristianos subtidal from fine sands (150– 180 µm, median particle size). The organic matter content ranged from 0.006% to 1.01% and 19.32–27.35% carbonates.

Figures

FIGURE 3. Setosabatieria triangularis sp. nov. Holotype. Male. A. Anterior end. B. Posterior end. Scale, A = 13 m, B = 16 m.