Xiphoniscus adisi Grangeiro & Souza & Christoffersen 2017, sp. nov.
Creators: name: Grangeiro, Daniela C.
name: Souza, Leila A.
name: Christoffersen, Martin L.
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Isopoda
Philosciidae
Xiphoniscus
Xiphoniscus adisi

description: Xiphoniscus adisi sp. nov.
(Figs 1−6)
Material examined. Holotype. male, Brazil, Amazonas State, Tarumã Mirim river: secondary forest, 03º02’S, 60º17’W, 17/II/1982, J. Adis et al. col. (INPA 2111).
Paratypes. 1 female, Brazil, Amazonas State, Tarumã Mirim river: secondary forest, 03º02’S, 60º17’W, 17/II/ 1982, J. Adis et al. col. (INPA 2112); 1 male, Brazil, Amazonas State, Tarumã Mirim river: secondary forest, 03º02’S, 60º17’W, 01/II/1982, J. Adis et al. col. (INPA 2113); 1 male, 1 female, Brazil, Amazonas State, Tarumã Mirim river: secondary forest, 03º02’S, 60º17’W, 25/VIII/1982, J. Adis et al. col. (MNRJ 25222); 1 male, 4 female, Brazil, Amazonas State, Tarumã Mirim river: secondary forest, 03º02’S, 60º17’W, 20/XII/1982, J. Adis et al. col. (INPA 2114); 1 male, 1 female, Brazil, Amazonas State, Tarumã Mirim river: secondary forest, 03º02’S, 60º17’W, 30/XII/1982, J. Adis et al. col. (MNRJ 25223).
Diagnosis. Eyes with 6 ommatidia. Molar penicil of mandible with five branches, one larger and four smaller. Pereonite 2 with coxal plate elongate caudally, reaching pereonite 3 and overlapping it. Apex of male pleopod 1 endopodite with three teeth.
Description. Largest male, 3 mm in length and 0.9 mm in width; largest non-ovigerous female, 2.7 mm long and 0.89 mm wide. Habitus elongate and narrow; not pigmented. Smooth tergal surface with small setae covering cephalothorax, pereon and pleon (Fig. 1B). Cephalothorax with frontal lobe weakly developed; lateral lobes inconspicuous. Linea frontalis thin; linea supraantennalis strongly marked at extremities and lightly marked near the center. Eyes with six ommatidia (Fig. 1A). Pereon with noduli laterales flagelliform, more dorsally inserted on coxal plate IV (Fig. 1A); gland pores absent. Pleon narrower than pereon; pleon epimera 3–5 small. Pleotelson broad, triangular, with slightly rounded tip and straight sides.
First antenna with median article shortest, proximal article longest and distal article with two apical and five subapical aesthetascs (Fig. 1C).
Second antenna with short setae and simple spines; flagellum triarticulate: distal article longest, proximal and median articles subequal; apical organ longer than distal article, with short free sensillae (Fig. 1D).
Mandibles with molar penicil with five branches, one larger and four smaller. Right mandible with two penicils and many setae on lacinia mobilis and one more penicil between molar and incisive processes (Fig. 2A). Left mandible with two penicils and many small setae on lacinia mobilis (Fig. 2B).
First maxilla mesal endite with 2 equal penicils; lateral endite with 4 teeth (one of which smaller) + 5 cleft teeth (Fig. 2E).
Second maxilla lateral lobe with distal margin rounded and about twice as long as the medial lobe, latter with simple setae, one group of 6 long ones and 2 setae near lateral lobe (Fig. 2D).
Maxilliped basipodite with spines and tricorn-like setae; endite with one tooth near the laterodistal edge, strong tooth caudally and rostral surface bearing setal tuft; palp with long lateral setae, proximal setal tuft reduced to single seta, medial tuft composed of many setae and medial spine present on proximal article (Fig. 2C).
Pereopods with simple setae (Fig. 4A, B), except for setae on carpus of pereopod 1 with shredded apex; dactyli with diminute inner claw. Pereopod 1 carpus on frontal face with a dense, longitudinal brush (Fig. 4A).
Pleopods respiratory fields absent. Exopod of pleopod 5 triangular, with two sensory setae laterally (Fig. 3E). Uropods endopodite and exopodite almost the same size, despite the endopodite subapical insertion.
Male sexual characters – pleopod 1 exopod broad, almost triangular, with rounded apex; endopod with distal part projected outwards, truncate apically, with apex bearing three lateral teeth directed proximally (Fig. 3A, B). Pleopod 2 exopod triangular, with two setae laterodistally and row of small setae along the medial margin; endopod long in relation to exopod (Fig. 3C, D). Exopod of pleopod 5 without a row of pectinate setae (Fig. 3E) (present in female) (Fig. 5B).
Etymology. The species name is a homage to Dr. Joachim Ulrich Adis (in memoriam) for steadily supplying material from the Amazon.
Remarks. Xiphoniscus mirabilis and X. adisi sp. nov. strongly resemble each other in the shape of endopod of pleopod 1 of the male (in both species the distal portion of the endopod is turned outwards and has spines) and in coxal plate 2 of the male, which is elongate, shaped like a spine in both species. The coxal plate shaped like a spine is an autapomorphy of Xiphoniscus. Xiphoniscus adisi sp. nov. differs from X. mirabilis in: 1) Coxal plate prolonged, reaching posterior edge of pereonite III and overlapping it (Fig. 1A, B), versus reaches the medial part of pereonite IV, extending parallel to its lateral edge in X. mirabilis, although the illustration provided by Leistikow (2000b) shows the prolongation of coxal plate reaching the posterior edge of pereonite 3 only. 2) Six ommatidia (Fig. 1A), versus 7 −8 in X. mirabilis. 3) First antenna with 2+5 aesthetascs (Fig. 1C), versus 2+ 6 in X. mirabilis. 4) Molar process of the mandible with 5 penicils: 1+4 (Fig. 2A, B), versus 4: 1+ 3 in X. mirabilis. 5) Lateral endite of first maxilla with 4+5 teeth (Fig. 2E), versus 4+ 4 in X. mirabilis. 6) Second maxilla without trichiform setae or pectinate scales on lateral lobe, and with group of 6 long setae on medial lobe (Fig. 2D), versus with trichiform setae and pectinate scales on lateral lobe, and without long setae on medial lobe in X. mirabilis. 7) Maxilliped endite with one tooth near the laterodistal edge; a knob-like penicil on rostral surface was not seen (Fig. 2C) versus endite with two teeth caudally and knob-like penicil rostrally in X. mirabilis. 8) Endopod of male pleopod 1 with apex truncate (Fig. 3A), versus apex acute in X. mirabilis. 9) Three teeth in the apex of pleopod 1 endopod, versus four teeth in X. mirabilis. 10) The position of noduli laterales (Fig. 6).
Both X. adisi sp. nov. and X. mirabilis occur in the Amazon (Fig. 7), in Brazil and in Ecuador (Puyo), respectively. Sigrist & Carvalho (2009) note that the Amazon is considered a hybrid area, as shown in phylogenetic studies. The Amazonian region can be divided into three main subregions, corresponding to endemic areas: Northern Amazon, Southwestern Amazon and Southeastern Amazon (Fig. 7). X. adisi sp. nov. occurs in the Northern Amazon subregion and X. mirabilis in the Southwestern Amazon subregion. X. mirabilis was recorded by Vandel (1968) at an altitude of 800 m in Puyo and of 2.300 m in Baños, both cities located in Ecuador. X. adisi sp. nov. was collected in a secondary forest in the Tarumã-Mirim river. This river (a brook) is located 68 m above sea level (Google Earth). It is a tributary of the Negro river, in the vicinity of Manaus, Brazil, and is seasonally flooded by black waters (Ferreira & Parolin 2011).
The character “prolonged coxal plate II” or “coxal plate shaped like a spine”, which is an autapomorphy of Xiphoniscus, reveals new states with the addition of X. adisi sp. nov. to the genus. The possible states of this character refer to the size and position of this coxal plate, which are different in the two species. The discovery of new Xiphoniscus species should lead to this character's unfolding into many states and enable proper polarization for the establishment of relationships between the species based on synapomorphies.
description: Published as part of Grangeiro, Daniela C., Souza, Leila A. & Christoffersen, Martin L., 2017, New species of Xiphoniscus and new record of Androdeloscia escalonai (Isopoda, Scutocoxifera, Oniscidea, Philosciidae) from Brazilian Amazon in Zootaxa 4350 (2), DOI: 10.11646/zootaxa.4350.2.11, http://zenodo.org/record/1053082