Chromadora serrambi, 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 : 50-56

Chromadora serrambi sp. nov.

( Figures 1–4 , Table 1)

http://zoobank.org/ 4FDD4AB1-F6F8-4A3A-89F8-7EDB0330B8A2

Type material. Holotype male ( MOUFPE 0001 ), paratype female ( MOUFPE 0002 ), others paratypes: 5 males (443–447 NM LMZOO-UFPE) and 5 females (448–452 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 ‘serrambi’ is given because this species was found in a coral reef located on Serrambi beach. In addition, the species has a unique characteristic (autapomorphy) and for this reason the collection site was chosen for its name.

Description. Holotype (Male). Body cylindrical, 597 µm long. Maximum body diameter 23 µm, anterior region attenuated, head diameter 9 µm (45% 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. This pattern is homogeneous throughout the body extension. Cephalic arrangement 6+6+4, inner and outer labial sensilla papilliform; cephalic setiform sensilla measuring 0.7 times head diameter. Amphideal fovea difficult to see (the same condition was observed in all analyzed specimens). Buccal cavity armed with three solid teeth, one dorsal and two ventral, dorsal tooth larger and curved. Secretory–excretory pore located 9 µm from anterior end (0.7 times head diameter). Secretory–excretory gland posterior to pharynx with two cells present, one well developed measuring 46 µm (proximal) and one of reduced size (7 µm). Ocelli situated 19 µm from anterior end and nerve ring located 65 µm from anterior end, posterior to middle of pharynx length. Pharynx with rounded bulb, occupying 23% of pharynx length; anterior muscle interruption can be viewed. The reproductive system with a single outstretched testis. Spicules 1.3 times the cloacal body diameter, curved and cephalated. Gubernaculum narrow, occupying 68% of spicule length, with expanded distal portion, embracing the spicules. Pre-cloacal supplements absent. Tail conical-elongated measuring 6.1 times cloacal body diameter, with a small spinneret (4 µm).

Paratypes (Females). Very similar to male. 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 anteriorly to mid-body region (47–48.7% of total length). Tail 5.8–7.4 times anal body diameter.

Diagnosis. Chromadora serrambi sp. nov. is characterized by a simple bulb, cephalic setae 0.6–0.7 times head diameter in male and 0.7–0.9 in female. Secretory-excretory pore 0.7–0.9 times head diameter from anterior end. Ocelli present. Spicules 1–1.3 times cloacal body diameter. Gubernaculum narrow (60–68% of spicule length), with expanded distal portion, embracing the spicules. Precloacal supplements absent. Tail conical-elongated with a small spinneret (5.5–6.4 times cloacal body diameter in male and 5.8–7.4 times anal body diameter in female).

Differential diagnosis (Relationships). Chromadora serrambi sp. nov. is the only Chromadora species where pre-cloacal supplements are absent which facilitates its identification. In relation to the gubernaculum, C. macrolaimoides presents a similar shape (distal expansion), however it seems to be less developed (smaller and less sclerotized) in the new species (11–14 µm vs. 18–23 µm). The anterior region (position of the ocelli and secretoryexcretory pore, bulb shape) is similar to that observed in C. nudicapitata redescribed by Kito (1978a,b).

Figures

FIGURE 1. Chromadora serrambi sp. nov. holotype male: (A) overview, (B) anterior region (buccal cavity, cephalic setae, secretory-excretory pore, ocelli and cuticle), (C) anterior region (pharynx posterior bulb and secretory-excretory gland), (D) posterior end (tail and cuticle), (E) spicules and gubernaculum.

FIGURE 2. Chromadora serrambi sp. nov. holotype male: (A) anterior region, (B) anterior region (cuticle), (C) anterior region (buccal cavity, arrow marks secretory-excretory pore), (D) posterior end (tail), (E) posterior end (cuticle), (F) pharynx posterior bulb and secretory-excretory gland, (G) spicules and gubernaculum.

FIGURE 3. Chromadora serrambi sp. nov. paratype female (MOUFPE 0002): (A) overview, (B) anterior region (buccal cavity, cephalic setae, secretory-excretory pore, ocelli and cuticle), (C) anterior region (pharynx posterior bulb and secretory-excretory gland), (D) posterior end (tail and cuticle).

FIGURE 4. Chromadora serrambi sp. nov. paratype female (MOUFPE 0002): (A) anterior region (pharynx posterior bulb and secretory-excretory gland), (B) anterior region (cuticle), (C) anterior region (buccal cavity, arrowhead marks secretory-excretory pore), (D) posterior end (tail), (E) posterior end (cuticle), (F) reproductive system (arrow marks vulva).