Chromadora pernambucana, Neres & Santos & Esteves, 2021

Neres, Patrícia Fernandes, Santos, Paulo Jorge Parreira Dos & Esteves, André Morgado, 2021, New chromadorid nematodes from Brazilian coral reefs: a taxonomic contribution to Chromadora Bastian, 1865, Zootaxa 5032 (1), pp. 47-79 : 56

Chromadora pernambucana sp. nov.

( Figures 5–8 , Table 2)

http://zoobank.org/ 569F0CD3-628F-4D7C-8E0D-776A76793B21

Type material. Holotype male ( MOUFPE 0003 ), paratype female ( MOUFPE 0004 ), others paratypes: 5 males (453–457 NM LMZOO-UFPE) and 5 females (458–462 NM LMZOO-UFPE).

Type Locality. Serrambi beach (S 8°33’31.5” W 35°00’16.7”), located on the southern coast of the State of Pernambuco, in the Northeastern region of Brazil .

Etymology. The specific epithet ‘pernambucana is given because this species was found in Serrambi beach, Pernambuco State (Northeastern Brazil).

Description. Holotype (Male). Body cylindrical 608 µm long. Maximum body diameter 23µm, anterior region attenuated, head diameter 9 µm (42% of body diameter in pharynx end). Annulated cuticle with transversal rows of small dots. Lateral longitudinal differentiation represented by four rows of larger and more spaced dots. In tail region, these larger dots appear to be closer to each other, forming an almost a longitudinal line. Cephalic arrangement 6+6+4, inner and outer labial sensilla papilliform; cephalic setiform sensilla measuring 0.4 times head diameter. Amphideal fovea transversely elliptical occupying 44.4 % of corresponding body diameter, located 3 µm from anterior end. Buccal cavity armed with three solid teeth, one dorsal and two ventral, dorsal tooth larger. Secretory–excretory pore at cephalic setae level (3 µm from anterior end). Secretory–excretory gland posterior to pharynx with two cells present, one well developed measuring 72.5 µm (proximal) and one of reduced size (10.5 µm). Ocelli not observed (the same was found in all analyzed specimens). Nerve ring located 66 µm from anterior end, posterior to middle of pharynx length. Pharynx with terminal bulb (17.5 µm in diameter), occupying 24.5% of pharynx length. The reproductive system with a single outstretched testis. Spicules curved 1.4 times the cloacal body diameter. Gubernaculum almost the size of the spicule (83% of spicule length), embracing it in its posterior half; distal portion pointed. Three pre-cloacal supplements, two cup-shaped (2 µm) little sclerotized, located 8 µm and 18.5 µm from the cloaca, and one papilla-shaped situated just before the cloaca. Post-cloacal supplement (papilla like) 50 µm from cloaca (0.6 times tail length). Tail conical measuring 4.8 times cloacal body diameter, with a small spinneret (3 µm).

Paratypes (Females). Very similar to male, but its tail is slightly larger 5.3–6.2 times anal body diameter. Reproductive system amphidelphic with reflexed ovaries with branches bent in opposite directions. Anterior gonad to the right of the intestine and the posterior gonad to the left of the intestine. Vulva located next to mid-body region (49–51% of total length).

Diagnosis. Chromadora pernambucana sp. nov. is characterized by simple bulb, cephalic setae 0.4–0.5 times head diameter. Secretory-excretory pore at cephalic setae level. Ocelli not observed. Spicules 1.3–1.4 times cloacal body diameter. Gubernaculum almost the size of the spicule (73–84% of spicule length), embracing it in its posterior half; distal portion pointed. Three pre-cloacal supplements, two cup-shaped, weakly sclerotized and one papillashaped situated just before the cloaca. Distance between supplement one (S1) and supplement two (S2) 0.13–0.22 times tail length and between S2 and papilla (supplement 3 – S3) 0.07–0.2 times tail length. Post-cloacal papilla next to tail end (0.6–0.8 times tail length). Tail conical with a small spinneret (4.5–5.1 times cloacal body diameter in male and 5.3–6.2 times anal body diameter in female).

Differential diagnosis (Relationships). Chromadora pernambucana sp. nov. it is differentiated from other species of the genus by the shape of the gubernaculum, which extends to middle its length, embracing the spicules, and with a distal region point; in addition, it has three supplements of which two are cup-shaped (small and slightly sclerotized) and another pre-cloacal papilla very close to the cloaca. Chromadora micropapillata also presents this papilla proximate and anterior to the cloaca, but these species differ in the shape of the gubernaculum.

Figures

FIGURE 5. Chromadora pernambucana sp. nov. holotype male: (A) overview, (B) anterior region (buccal cavity, cephalic setae, secretory-excretory pore and cuticle), (C) anterior region (pharynx posterior bulb and secretory-excretory gland), (D) posterior end (tail and cuticle), (E) pre-cloacal supplements, spicules and gubernaculum.

FIGURE 6. Chromadora pernambucana sp. nov. holotype male: (A) anterior region and secretory-excretory gland, (B) anterior region (buccal cavity), (C) pharynx posterior bulb, (D) posterior region (spicules, gubernaculum and pre-cloacal supplements, arrow marks papilliform pre-cloacal supplements), (E) posterior end (tail, arrow marks post-cloacal papilla), (F) posterior end (cuticle).

FIGURE 7. Chromadora pernambucana sp. nov. paratype female (MOUFPE 0004): (A) overview, (B) anterior region (buccal cavity, cephalic setae, secretory-excretory pore and cuticle), (C) anterior region (pharynx posterior bulb and secretory-excretory gland), (D) posterior end (tail and cuticle).

FIGURE 8. Chromadora pernambucana sp. nov. paratype female (MOUFPE 0004): (A) anterior region and secretory-excretory gland, (B) anterior region (buccal cavity), (C) anterior region (cuticle), (D) pharynx posterior bulb, (E) posterior end (tail), (F) reproductive system.