Daptonema matrona, Neres & Fonseca-Genevois & Torres & Cavalcanti & Castro & Silva & Rieger & Decraemer, 2010

Neres, Patricia Fernandes, Fonseca-Genevois, Verônica Gomes Da, Torres, Rodrigo Augusto, Cavalcanti, Mariana Da Fonseca, Castro, Francisco José Victor De, Silva, Neyvan Renato Rodrigues Da, Rieger, Tania Tassinari & Decraemer, Wilfrida, 2010, Morphological and molecular taxonomy of a new Daptonema (Nematoda, Xyalidae) with comments on the systematics of some related taxa, Zoological Journal of the Linnean Society 158 (1), pp. 1-15 : 4-8

publication ID	https://doi.org/ 10.1111/j.1096-3642.2009.00528.x
persistent identifier	https://treatment.plazi.org/id/71735D29-D356-3E61-3259-F980FC394BC4
treatment provided by	Felipe
scientific name	Daptonema matrona
status	sp. nov.

Treatment

DAPTONEMA MATRONA SP. NOV.

Description

Material studied: 11 males; 11 females.

Material type: Material type: Holotype and allotype deposited in the National Museum of Rio de Janeiro. Paratypes slide deposited in the Laboratório de Meiofauna Departamento de Zoologia , Universidade Federal de Pernambuco, Recife, Brazil .

Type specimens: Male holotype MNRJ 337 View Materials ; Female allotype: MNRJ 338 View Materials ; male paratypes 123–132 NM LMZOO-UFPE; female paratypes 133–142 NM LMZOO-UFPE .

Locality: Pina Basin (Recife, Pernambuco, Brazil): estuarine intertidal silt-clay sediments.

Measurements: See Tables 1 and 2.

Etymology: The species’ Latin name (matrona = mother family) is based on the method of reproduction by the female i.e. intra-uterine hatching and development.

Holotype: Elongated body, hardly narrowed anteriorly ( Figs 1A View Figure 1 , 2A View Figure 2 ); cephalic and pharynx base diameter corresponding to 40 and 84% of the maximum body diameter, respectively. Cuticle transversely striated, striations relatively fine (1.8 Mm) ( Figs 1B View Figure 1 , 3B View Figure 3 ). Somatic setae short and distributed along the body but more concentrated/numerous in the neck and caudal regions ( Fig. 1A View Figure 1 ). Head rounded with six distinct lips, each one with a labial papilla ( Fig. 3A View Figure 3 ). Twelve cephalic setae in six pairs, the longer ones measuring 3 Mm (12% of the cephalic diameter) and the shorter ones 1.8 Mm (7% of the cephalic diameter) ( Fig. 1B View Figure 1 ; Table 1).One circle of subcephalic setae ( Fig. 1B View Figure 1 ). Buccal cavity conical, with an annular reinforcement delimiting the stoma from the anterior part of the cavity ( Fig. 1B, C View Figure 1 ). Amphidial fovea circular, 21.8% of corresponding body diameter and located 13.2 Mm behind anterior end ( Figs 1B View Figure 1 , 2C View Figure 2 , 3C View Figure 3 ). Secretory–excretory pore at 42 Mm and the nerve ring at 81.6 Mm from the anterior end ( Table 1). Pharynx cylindrical, surrounding stoma ( Figs 1C View Figure 1 , 2B, D View Figure 2 ). Cardia with irregular form and partially inserted in the intestine ( Fig. 1G View Figure 1 ). Ventral gland not visualized. Single testis located on the left of the intestine, reaching almost to the base of pharynx ( Fig. 1A View Figure 1 ). Five ejaculatory glands extending 354.5 Mm anteriorly to the anal opening ( Fig. 1D View Figure 1 ). Spicules cephalate proximally, 0.7¥ anal body diameter long and almost straight ( Figs 1F View Figure 1 , 2E View Figure 2 ). Gubernaculum without apophysis ( Fig. 1F View Figure 1 ) and with the distal region wingshaped ( Fig. 3D View Figure 3 ). Four pairs of setae posteriorly to the anal opening, next to the cylindrical region of the tail, on the ventral side ( Fig. 1E View Figure 1 ). Tail conical–cylindrical 4.8¥ anal body diameter long, the cylindrical region corresponding to 30.7% of the total tail length, with two terminal setae (9 Mm) ( Fig. 1E View Figure 1 ; Table 1). Three caudal glands present ( Figs 1E View Figure 1 , 2F View Figure 2 ).

Allotype: Female largely similar to male ( Fig. 4 View Figure 4 ) but showing sexual dimorphism in size of amphidial fovea, i.e. smaller than in male. Amphidial fovea round, its diameter 14.5% of corresponding body width and located 13.2 Mm or 0.46 cephalic diameters from anterior end ( Fig. 4B View Figure 4 ; Table 2). Secretory– excretory pore at 40.2 Mm and the nerve ring 100.8 Mm behind anterior end ( Table 2). Single ovary located left of intestine and extending almost to base of pharynx. A short prevulval uterine sac (spermatheca) in the second third of the body length. Vulva close to anus, i.e. at 73.8% of total body length from anterior end ( Fig. 4A View Figure 4 ). Reproduction apparently by ovoviviparity. Up to 45 eggs as well as first and second stage juveniles observed within the uterus of a single specimen.

GENETIC AND PHYLOGENETIC ANALYSES

Neighbour-joining topology revealed the existence of two large genetic groupings ( Fig. 5 View Figure 5 ). The first characterized by the lineage of the genus Theristus and Daptonema normandicum , the latter of which is genetically closer to Theristus agilis . Such a grouping emerged as a genetic sibling lineage to the other grouping, which united Theristus acer and Theristus sp. The second large genetic grouping revealed the genetic unity of the remaining species of Daptonema and a Metadesmolaimus sp. Daptonema matrona sp. nov. emerged as a genetic sibling lineage of Daptonema oxycerca and Daptonema procerum . Such a grouping emerged as the genetic sibling lineage to the other remaining group composed of Daptonema hirsutum , Daptonema setosum + Daptonema sp. , besides Metadesmolaimus sp. ( Fig. 5 View Figure 5 ). Daptonema hirsutum and D. setosum presented identical sequences. Daptonema oxycerca + D. procerum are genetically close lineages.

Maximum parsimony topology was represented by the consensus of 28 153 equally parsimonious trees. A total of 1416 characters was analysed, 945 of which were constant, 270 were parsimoniously informative, and 201 were parsimoniously non-informative. The length of the consensus tree was 887 steps; retention and consistency indexes were 0.7934 and 0.7193, respectively. The analysis revealed the existence of two monophyletic clades ( Fig. 6 View Figure 6 ). The first clade was formed by Daptonema normandicum and the Theristus sp ecies, in which Theristus agilis and D. normandicum emerged as an evolutionary sibling lineage to the other grouping, which united T. acer and Theristus sp. The second clade was formed by the other Daptonema species , including the new species and Metadesmolaimus sp. Daptonema matrona sp. nov. was characterized as an evolutionarily distinct branch and a sibling group of the other congeneric species, with the exception of D. normandicum . Daptonema procerum and D. oxycerca were revealed to be sister groups. This evolutionary unit also emerged as a sister group of D. setosum , Daptonema sp. , D. hirsutum + Metadesmolaimus sp. ( Fig. 6 View Figure 6 ). The analysis also revealed a putative synonymy involving D. hirsutum and D. setosum as well as a well-supported monophyletic unit (98/97) encompassing diverse species of Daptonema and Metadesmolaimus sp. ( Fig. 6 View Figure 6 ).

Bayesian inference topology resulted from the majority rule consensus of 10 001 trees with a standard deviation of 0.005222, resulting from 1 000 000 generations computed in four Markov chains. The analysis also revealed the existence of two monophyletic groupings ( Fig. 7 View Figure 7 ). The first was formed by D. normandicum and the Theristus sp ecies (like that revealed in the MP topology), in which T. agilis and D. normandicum emerged as sister taxa to the other grouping, which united T. acer and Theristus sp. In the second grouping ( Fig. 7 View Figure 7 ) formed by the remaining species of Daptonema + Metadesmolaimus sp. , D. matrona sp. nov. exhibited the same phylogenetic status as seen in the MP topology, constituting a sibling group of D. oxycerca , D. setosum , D. procerum , D. hirsutum + Metadesmolaimus sp. Daptonema procerum and D. oxycerca were also revealed to be a sibling group of D. setosum , Daptonema sp. , D. hirsutum + Metadesmolaimus sp. ( Fig. 7 View Figure 7 ). The analysis also revealed two polytomies – the first involving D. hirsutum and D. setosum (as found in the previous analyses) and the second between D. procerum and D. oxycerca ( Fig. 7 View Figure 7 ).