Aplectana longa, Alcantara & Ferreira-Silva & Forti & Morais & Silva, 2021

Alcantara, Edna P., Ferreira-Silva, Cristiana, Forti, Lucas R., Morais, Drausio H. & Silva, Reinaldo J., 2021, A new species of Aplectana (Nematoda: Cosmocercidae) in the Marsupial frog Gastrotheca microdiscus (Amphibia: Hemiphractidae) from Brazil, Zootaxa 4908 (3), pp. 426-434 : 428-432

Species: Aplectana longa n. sp. Alcantara and Silva

urn:lsid:zoobank.org:act:19D094D4-5F84-4724-9F6D-CD6FE41CEE70

( Figs 2–4 )

General morphology: Large and slender worms. Females much longer than males. Lateral alae absent, Cuticle transversely striated. Triangular oral opening surrounded by one dorsal lip with two cephalic papillae, and two subventral lips with one cephalic papilla and one amphid each ( Fig. 4C ). Oesophagus divided into a short pharynx, a long corpus, a small isthmus, and a large valved oesophageal bulb. Excretory pore situated at the junction of isthmus and oesophageal bulb ( Fig. 2B , 4B ). Somatic papillae distributed in four rows (two ventral and two dorsal) along the body in both sexes.

Male: (based on one holotype and one paratype) Body length 5.6–6.5 mm (6.5 mm), width at midbody 356.9– 432.1 (356.9) ( Fig. 2A ). Oesophagus 584.8–605.3 (605.3) long and 50.2–60.7 (60.7) width at midbody, pharynx 49.7–61.2 (61.2) long and 28.6–39.9 (39.9) wide, corpus 430.4–554.3 (554.3) long, isthmus 44.8–51.2 (51.2) long, bulb 89.9–109.1 (89.9) long and 96.2–110.4 (96.2) wide. Nerve-ring 264–328 (328) and excretory pore 490.5–568 (568) from anterior end ( Fig. 2B ). Caudal papillae larger than somatic. Cloacal papillae arranged as follows: 9 pairs of precloacal papillae distributed in two rows, the first pairs close to cloaca smaller than the other 8 pairs; one unpaired precloacal papilla; 6 pairs of postcloacal, 5 ventral pairs and one laterodorsal pair. Papillae pattern: 9+1:0:6 ( Fig. 2C ). Spicules similar in length, 232.2–258.3 (232.2) long, thin, with lateral portion more sclerotized than medial portion, pointed at distal end and with slight dilation at proximal end (2C, 3A). Small gubernaculum, 55.1–56.9 (56.9) long, thin, weakly sclerotized, pointed at distal end and with a curved proximal end, presenting a small and punctiform papilla-like dilation ( Fig. 2C , 3B ). Tapered tail 347.1–359.3 (359.3) long, ending in a slender filament, 95 in length ( Fig. 2A,C ).

Female: (allotype and 7 paratypes). Females much longer than males. Body length 10.7–20.8 mm (10.7 mm), width at midbody 533.5–591.7 (533.5) ( Fig. 4A ). Oesophagus 565.6–715.8 (565.6) long and 54.8–73.2 (55.6) wide, pharynx 50.5–75.9 (50.5) long and 37.7–57.1 (37.7) wide, corpus 426.9–565.6 (426.9) long, isthmus 35.6– 59.9 (38.2) long, bulb 97.8–127.3 (102.7) long and 108.8–136.9 (108.8) wide. Nerve ring 301.2–381.6 (301.2) and excretory pore 538.1–670.7 (538.1) distance from anterior end ( Fig. 4B ). Vulva situated in the middle of the body, 5.1–9.9 mm (5.1mm) from anterior end ( Fig. 4A,F ). Didelphic and prodelphic gonads. Muscular ovijector, joining 2 uteri; 1 directed anteriorly and 1 posteriorly. Posterior region of uterus flexed anteriorly before reaching anal region. Ovaries directed anteriorly, both anterior to vulva ( Fig. 4A,F ). Eggs in uteri, thin-shelled, embryonated, numerous, and in various stages of development up to larvae, 100.1–121.3 (n = 50) long 43.9–77.7 (n = 50) wide ( Fig. 4E ). Tail conical 625.4–900.3 (644.7) with a terminal filiform prolongation 141.9–174.8 (141.9) ( Fig. 4A,D ).

Taxonomic summary. Type host: Gastrotheca microdiscus (Andersson in Lönnberg & Andersson, 1910) deposited at Museu de Zoologia “Prof. Ad„o José Cardoso”, Universidade Estadual de Campinas (Unicamp), Campinas, S „o Paulo, Brazil ( ZUEC-AMP 24039–24042 ); Collection date 31 August 2017 .

Type locality: Trilha da Represa, Parque Estadual Carlos Botelho (-24.062317°; -47.992336°), S„o Miguel Arcanjo, S„o Paulo.

Site of infection: Small intestine.

Type specimens: Holotype male ( CHIOC 38977 ); allotype female ( CHIOC 38978 ); paratypes ( CHIOC 38978 b; CHIBB 9195-9196 ).

Etymology: The epithet longa is from the Latin (huge, enormous, unusually large) and refers to the body size of the new species.

Remarks. Aplectana longa n. sp. differs from all congeneric species by the combination of a unique set of morphological characters including the following: 1) large body size in both sexes; 2) lateral alae absent; 3) a small, thin, weakly sclerotized gubernaculum present, pointed at the distal end and curved proximally at the end, with a small and punctiform papilla-like dilation, and 4) Caudal papillae arrangement (9+1:0:6).

The presence of lateral alae is reported in all Aplectana spp.. However, these alae are absent in Aplectana longa n. sp., distinguishing the new species from its congeneric species.

Aplectana longa n. sp. has a small gubernaculum. Among the 56 species of Aplectana described worlwide, 44 have a gubernaculum, including the following species: A. acuminata (Schrank, 1788) Railliet & Henry, 1916 , A. adaechevarriae Ramallo, Bursey and Goldberg, 2008 , A. albae Adamson and Baccam, 1988 , A. brygooi Baker, 1980 , A. brumpti Travassos, 1931 , A. capensis Baker, 1981 , A. chamaeleonsis (Baylis, 1929) Travassos, 1931 , A. courdurueri Chabaud & Brygoo, 1958 , A. degraaffi Baker, 1981 , A. duttaphryni Sou, Sow & Nandi, 2018 , A. elenae Baker and Vaucher, 1986 , A fujianae Bursey, Goldberg & Kraus, 2011 , A. haianensis Bursey, Goldberg & Grismer, 2018 , A. hamatospicula Walton, 1940 , A. herediaensis Bursey, Goldberg and Telford, 2006 , A. hylae Wang, 1980 , A. hylambatis , A. incerta Caballero, 1949 , A. itzocanensis Bravo Hollis, 1943 , A. krausi Bursey & Goldberg, 2007 , A. leesi Hristovki et Riggio, 1975 , A. linstowi Yorke et Maplestone, 1926 , A. lopesi Silva, 1955 , A. macintoshii (Stewart, 1914) Travassos, 1931 , A. membranosa , A. mexicana (Caballero, 1933) Ballesteros–Marquez, 1945 , A. micropenis Travassos, 1925 , A. nebulosa Piñeiro Gomez, González and Sanabria , A. nordestina Amorim, Silva, Morais, Silva and Ávila 2017 , A. novaeguineae Bursey, Goldberg & Kraus, 2011 , A. novaezelandiae Baker & Green, 1988 , A. paraelenae Baker and Vaucher, 1986 , A. paucipapillosa Wang, 1980 , A. praeputialis (Skrjabin, 1916) , A. pusilla Miranda 1924 , A. raillieti Travassos, 1925 , A. ranae (Walton, 1931) Baker, 1980 , A. ryšavýi Barus and Coy Otero, 1969 , A. samarensis Bursey, Goldberg, Siler and Brown, 2018 , A. travassosi (Gomes and Motta, 1967) Baker, 1980 , A. tucumanensis Ramallo, Bursey and Goldberg, 2008 , A. unehi Falcón-Ordaz, Monks, Pulido-Flores & Rodriguez-Amador, 2014, A. vellardi and A. zweifeli Moravec & Sey, 1986 ( Bursey et al. 2018, Amorim et al. 2017, Piñeiro Gomez et al. 2017). However, only A. degraaffi , A. brygooi , A. courdurueri , A. incerta , A. paraelenae , A. pusilla , A. macintoshii , A. leesi , A. linstowi , A. herediaensis , A. mexicana , A. hylae , A. nebulosa , and A. nordestina have a gubernaculum ranging similarly to Aplectana longa n. sp. ( Bursey et al. 2018, Amorim et al. 2017, Piñeiro Gomez et al. 2017). Nevertheless, the morphology of the gubernaculum of the new species is unique and different from all these species.

According to Piñeiro Gomez et al. (2017), Aplectana spp. can be divided into two groups, the first including species with one unpaired precloacal papilla and the second with species in which this papilla is absent. Aplectana longa n. sp. belongs to the first group. Relating to the species presenting gubernaculum and the unpaired precloacal papilla (group one), the new species has papillae formula (9+1:0:6) different from the species A. acuminata (numerous and variable + 1), A. albae (6–7+1:1:5), A. brygooi (8+1:0:6–7), A. capensis (numerous + 1), A. courdurueri (7+1:1:6), A. degraaffi (4–5 +1:3:6), A. elenae (8+1:1:5), A. hamatospicula (4+1:0:7), A. hylambatis (5–4+1:1–2:5–8), A. leesi (10–13+1:1:5), A. linstowi (10–12+1:0:6), A. macintoshii (numerous and variable + 1), A. membranosa (5+1:2:4), A. nebulosa (6–7+1:2:5), A. raillieti (8+1:0:5), A. novaezelandiae (numerous and irregular + 1), A. paraelenae (3+1:2:6), and A. zweifeli (8–10+1:0:9) ( Baker 1980, Piñeiro Gomez et al. 2017, Bursey et al. 2018, González et al. 2019). Only one species, A. chamaeleonsis ( Baker, 1980) , has the papillae formula identical to Aplectana longa n. sp. (9+1:0:6). However, the arrangement of precloacal papillae is very different from the new species. Aplectana chamaeleonsis has, on the anterior lip of the cloaca, 3 precloacal papillae pairs at the side of the unpaired papilla (see Baker 1980).

Figures

FIGURE 2. Male of Aplectana longa n. sp. (A) Male, entire, and lateral view. (B) Anterior end of the male lateral view. (C) Posterior end of male, lateral view. Scale bars: 500 µm (A) 200 µm (B), 250 µm(C). Note: Fig 2C—except for the last two postcloacal pairs and the unpaired precloacal papilla, the other papillae were represented only at on side of the body.

FIGURE 3. (A) spicules (arrow) and (B) gubernaculum (arrow) of Aplectana longa n. sp. Lateral view. Scale bars: 50 µm.

FIGURE 4. Female of Aplectana longa n. sp. (A) Female, entire, and ventral view. (B) Anterior end of female, lateral view. (C) Mouth, lips, papillae, and amphids, apical view. (D) Posterior end of female, ventral view. (E) Non-embryonated and embryonated eggs. (F) Vulva region, lateral view, showing the vulva, vagina, and ovijector, and the beginning on two uteri. Scale bars: 1 mm (A), 200 µm (B, C, D, F), 50 µm (E).