Spirinia elongata, Castro & Bezerra & Silva & Fonsêca-Genevois, 2006

Castro, Francisco José Victor De, Bezerra, Tânia Nara Campinas, Silva, Maria Cristina Da & Fonsêca-Genevois, Verônica, 2006, Spirinia elongata, sp. nov. (Nematoda, Desmodoridae) from Pina Basin, Pernambuco, Brazil, Zootaxa 1121 (1121), pp. 53-68 : 60-65

Species: Spirinia elongata sp. nov.

Male

Cylindrical elongated body with rounded head and conical tail (L= 1368–2079 µm). The cuticle is annulated (0.67–1µm) less obvious in the head region than in the tail. The internal labial sensilla are not visible. Six papilliform labial sensilla, four cephalic setae and four sub­cephalic setae present. The cephalic setae 3–5 µm are placed laterally on the median portion of amphideal fovea. The sub­cephalic setae 3.5–5 µm are situated on the neck region, posterior to the amphids. The somatic setae are shorter 2.5–4 µm present up to bulb region. The amphideal fovea is ventrally rounded in “loop” with external circular line. The buccal cavity has one very small subventral tooth and two small dorsal teeth and, that are dificult to see. The muscular pharynx has a developed terminal bulb occupying 62–86 % of the total corresponding body width, with cuticularized lumen and median plasmatic interruption. The nerve ring occupies 52–63 % of the total pharynx length. The specimens possess one anterior testis in to the left of intestine. The spicules are curved 52– 67 µm and the capitulum developed and velum sclerotized. The gubernaculum 24–28 µm is a laminar­like shape and enveloped by the distal portion of spicule. One pair of seta is laterally present in the precloacal region in front of the spicules. The tail is filliform and the annulations 0.67–1 µm are more evident on this region.Three caudal glands are visible. The two juveniles measured were in third and fourth stage. The morphological differences between juveniles were not seen

Female

The females are very similar to males, although some minor morphological differences can be observed. There is no apparent sexual dimorphism. The specimens size ranges from 1524 µm to 1762 µm. The size of cephalic setae varied from 3.5–5 µm and the sub­cephalic setae from 3–5 µm. The somatic setae are shorter 2.5–3.5 µm. The nerve ring occupies 52–67 % of the total pharynx length. The specimens possess two opposed and reflexed ovaries. The vulva occupies 37.5–42 % of the total body length.

Discussion

The new species closely resemble Spirinia septentrionalis described by Gerlach (1957) and Pastor de Ward (1988). However, the species was first described by Cobb (1914) and also by Wieser (1954). The geographic distribution of S. septentrionalis comprise: Antartida, Chile, Brazil, Hawaii and Argentina. The main morpholmetrical differences are shown in table 4.

The species described by Gerlach, formely known as S. parasitifera was only based on one males morphological features. Despite some morphological similarities, the new species has different features such as sub­cephalic setae, somatic setae all over the body and number and position of the teeth.

Although the reproductive system of specimens described by Pastor de Ward was similar to the new Brazilian species, the glands present in the two portions of the vulva were not seen.

The S. septentrionalis described by Wieser does not have subcephalic setae, but has somatic setae on the cervical region. The presence of the two dorsal teeth and one very small subventral tooth were observed in the new species, however, the specimen described by Wieser only had one dorsal tooth that was barely visible.

The subscephalic setae has a similar number of Spirinia gerlachi (Luc and De Coninck, 1959) Gerlach, 1963 and Spirinia schneideri (Villot, 1875) Gerlach, 1963 but both species are distinguished from S. elongata by the number and position of the teeth.

Based on morphological features Spirinia elongata differs from Spirinia species by the position of three teeth (two dorsal and one ventral).

According to Vincx and Gourbault (1989) among the nine valid species only Spirinia gerlachi (Luc and De Coninck, 1959) had one dorsal and two subventral teeth. Although the Brazilian species also has three teeth, they are differently positioned. S. elongata morphological features (number of subcephalic setae and presence and position of teeth) are compared with those of the other valid species in table 5.

species (NeMys database—http://intramar.rug.ac.be/taxondata).

Valid Species Subcephalic setae Presence and position od the teeth

Spirinia gerlachi (Luc & De Coninck, 1959) Not mentioned 1 dorsal and 1 ou 2 (?)

Gerlach, 1963 subventral teeth

Spirinia gnaigeri Ott, 1977 2 circles of 8 2 small subventral subcephalic setae

Spirinia granullata Allgén 1929 Not mentioned Not mentioned

Spirinia flagellata Vitiello, 1975 Not mentioned Not mentioned

Spirinia hamata Wieser, 1967 Not mentioned 3 teeth

Spirinia megamphida Vincx & Gourbault, 1989 Not mentioned Without teeth

Spirinia mokii Coles, 1987 4 cervical setae Without teeth

Spirinia laevioides Gerlach, 1963 Not mentioned 1 dorsal tooth

Spirinia papillata Vincx & Gourbault, 1989 8 cervical setae 1 dorsal and probably 2 ventralsublateral

Spirinia laevis (Bastian, 1865) Gerlach, 1963 2 cervical setae 1 dorsal tooth

Spirinia parasitifera (Bastian, 1865) Gerlach 1963 Not mentioned 1 dorsal e 2 subventral

Spirinia schneideri (Villot, 1875) Gerlach, 1963 4 subcephalic setae 1 dorsal tooth

Spirinia septentrionalis (Cobb, 1898) Gerlach, Not mentioned 1 dorsal tooth

1963

Spirinia tenuicaudata (Allgén, 1959) Gerlach, 1963 Not mentioned Not mentioned