Circoniscus ornatus, (VERHOEFF, 1941)

Schmidt, Christian, 2007, Revision of the Neotropical Scleropactidae (Crustacea: Oniscidea), Zoological Journal of the Linnean Society 151, pp. 1-339 : 68-69

CIRCONISCUS ORNATUS ( VERHOEFF, 1941)

Parcirconiscus ornatus Verhoeff, 1941 – Schmalfuss (2003 *).

Circoniscus gaigei – Andersson (1960); Lemos de Castro (1967); Schmalfuss (1980); Souza & Lemos de Castro (1991); Schultz (1995 *); Warburg et al. (1997); Souza-Kury (1998 *); Leistikow & Wägele (1999 *).

Circoniscus amazonicus Brasil Lima, 1996 – Souza- Kury (1998*); Leistikow & Wägele (1999 *); Schmalfuss (2003 *) – syn. nov.

Not: syn. of Circoniscus gaigei – Schmalfuss (1980); Leistikow & Wägele (1999 *).

Material examined

Type specimens: One ♀ without cephalothorax, broken in two halves and covered with mycelia, and five microscopic slides: (1) ♂ cephalothorax frontal, mouthparts, second antenna; (2) ♂ coxal plates 1 and 2 and pereiopods 1 and 2; (3) pleon segment 5 + pleotelson + uropods of ♂; (4) coxal plates and pereiopods 7 and pleopods 1–5 of ♂; (5) cephalothorax, mouthparts, second antenna [syntypes, Guyana (now: Suriname): Paramaribo, leg. A. Heyne, ZSM).

Other samples: Two ♂, two ♀ (paratypes of Circoniscus amazonicus ; Brazil, Amazonas, Rio Solimões, Ilha Marchantaria, 59°58′ W, 3°15′ S, leg. Chr. Martius, 22 April 1986, MNRJ 6845); two ♂, one ♀ ( Peru, Dept. Huánuco, Rio Yuyapichis, 9°37′ S, 74°56′ W, altitude 260 m, leg. M.v. Tschirnhaus, September 1981, cCS 137); six ♂, five of them broken into fragments, and three ♀ ( Brazil, Pará, Belém, Fazenda Velha, leg. O. Roppa, 11 November 1963, MNRJ 8512); one ♀ ( Peru, Panguana, ‘102-105 A1-3 Ex’, leg. Hanagarth, 23 November 1975, SMNS); one ♂ [ Peru, Panguana, ‘8 S A1 Ex yar’, leg. Hanagarth, 16 November 1975, SMNS); one ♂, one ♀ m (> habitus drawing], Peru, Panguana, ‘Caña breva Ex2’, leg. Hanagarth, 2 July 1975, SMNS]; six ♂, one immature ♂, four ♀ m, ten ♀, 14 juvenile /immature ( Peru, Panguana, ‘KL 1,2,3,4,5,6,7’, leg. Hanagarth, 20 September 1975 to 10 January 1976, SMNS); three ♂, one immature ♂, four ♀ m, three ♀, ten juvenile /immature ( Peru, Panguana, ‘Ku 1,2,4,5,8,11,12,13’, leg. Hanagarth, 1 May to 27 December 1975, SMNS); ten ♂, eight immature ♂, ten ♀ m, 12 ♀, 78 juvenile /immature ( Peru, Panguana, ‘Y 2,3,4,5,6,7,8,9,11’, leg. Hanagarth, 26 June to 27 December 1975, SMNS); five ♂, one immature ♂, seven ♀ m, nine ♀ without marsupium, nine juvenile /immature ( Peru, Panguana, ‘Ku 1,2,4,5,6,7,8,11,13’, leg. Hanagarth, 7 May 1975 to 10 January 1976, SMNS); four ♂, ten immature ♂, seven ♀ m, four ♀ without marsupium, 35 juvenile / immature ( Peru, Panguana, ‘Y 1,3,5,7,11,12’, leg. Hanagarth, 5 March to 27 December 1975, SMNS); six ♂, ten immature ♂, 27 ♀ m, four ♀ without marsupium, 45 juvenile /immature ( Peru, Panguana, ‘KL 1,2,4,5,6,7’, leg. Hanagarth, 12 June to 27 December 1975, SMNS); two ♂, two juvenile ( Peru, Panguana, leg. Hanagarth, ‘87.88 A 3.4. 16.11.75 Yar’, cCS 412); one juvenile ( Ecuador, ‘on roots of a bromeliad, pres. L. Kilby, M.A.F.F.’, without further data, BMNH 1982.456.1); one ♂, fragmented (‘ Guyana, Kartabo, A.M.N.H. 9019’, MNRJ 3180); one immature ♂, one ♀ ( Brazil, Amazonas, Tabatinga, leg. J. Candido e Argentina, 26 May 1950, MNRJ 3178); one ♂ ( Brazil, Amazonas, Manaus, Reserva Ducke, ‘sob cascos de arvore morta’, leg.?, 6 April 1966, MNRJ 3197); 25 ♂, 37 ♀ m, 18 ♀ ( Brazil, Amazonas, Manaus, 2°53′36″ S, 59°58′22″ W, under leaf litter of Cocos nucifera , Bactris gasipaes , Elaeis guineensis , leg. M. Garcia, 15 July 2002, cCS 478a).

Female specimens tentatively identified as Circoniscus ornatus : one ♀ ( Brazil, Pará, Belém, Museu Goeldi, ‘no chão’, leg. H. Schubart, January 1967, MNRJ 3179 ) ; one ♀ ( Brazil, Amazonas, Manaus, Reserva Ducke, leg. J. Becker, 30 July 1971, MNRJ 3196 ) ; one ♀ ( Brazil, bras. Guayana , upper Rio Paru do Oeste , Igarape , ‘ “ Komadeveni ” bei neuer Tintgo- Maloca’, leg. Sattler, 25 January 1961, SMF 11341) .

Description ( Figs 209–215 )

Male maximum about 11 mm long, 5.0 mm wide, cephalothorax 2.57–2.71 mm wide; largest non-ovigerous female 8.5 × 3.9 mm; ovigerous females 9.6 mm long, 4.2–5.1 mm wide, cephalothorax 2.66 mm wide.

Surface smooth. Tergites light brown with pale muscle insertion spots, margins pale; the extent of pale margins and the degree of contrast between dark and pale areas varies. Flagellum of second antenna always pale. Rest of second antenna ferrugineous in some specimens. Cephalothorax with frontal shield appressed to head; a weak transverse furrow can be seen in dorsocaudal view. Eyes composed of 18–24 ommatidia. First coxal plate with schisma of the shape that is typical for the genus. Second and following coxal plates without lobes etc.

First antenna three-jointed, with some aesthetascs on distal half of apical article. Apical cone slender, with one small lateral sensillum.

Mandibles with one penicil between lobe and pars molaris, the latter represented by a tuft of hairy setae. First maxilla lateral endite on distal margin with distal group of four stout teeth, a slender seta, and a triangular lobe. Mesal group of six slender teeth, five of them cleft. An extremely small subapical seta is present near the base of the mesal group. Mesal endite with two subequal penicils and a pointed laterodistal corner. Maxilliped endite rounded, covered with spines. Maxilliped palp basal article with inner large seta in mesal position; lateral seta typical for most Oniscidea absent. Second article with basal tuft of few setae and distal tuft of numerous setae on a socket on the mesal margin and two setae on the lateral margin. Distal article with apical tuft of setae and two setae on the lateral margin.

Pereiopod 1 with only a small field of scales on frontal face of carpus. Ischium 1 on ventrocaudal face with field of spines or scales. Male pereiopods 4–6 with fields of scales on ventral faces of merus and carpus. Male pereiopod 7 ischium on frontal face with a short distal ridge, ventral of this a field of scales. Ischium 7 with ventral scale-field and a small, semicircular ridge covered with scales on the frontal face. No differentiations are visible in caudal view on pereiopod 7. Pereiopod 7 with distinct irregular scale-rows in the base and indistinct scale-rows on ischium and merus, which are vestigia of the water-conducting structures. Dactyli with inner claw at most half as long as outer claw, ungual seta curved, basal accessory seta one-third as long as the ungual seta, dactylar seta with hirsute tip.

Male genital papilla with narrow ventral shield and lateral, subapical orifices exceeded by a truncate lobe. Male pleopod 1 endopodite with apex curved outwards. The dorsomesal row of setae changes from the dorsal (= caudal) face to the ventral face. At this location, a short distance of the row runs perpendicular to the longitudinal axis. Endopodite 2 exceeds exopodite in length. Male exopodite 5 with narrow, prolongated apex and medial furrow for endopodite 2. Dorsal face of exopodite 5 with field of pectinate scales. Pleopod 1–3 exopodites of males and females with dorsal, weakly wrinkled respiratory fields. Exopodites 4 and 5 with a marginal ridge that probably represents a vestigium of a respiratory field.

Pleotelson triangular with concave sides. Uropod sympodites with distal margin at least two times as wide as the exopodites, with more or less distinct angle on the outer corner. Exopodites conical, short, hardly projecting beyond the body outline.

In immature males of width 3.5 mm, the pereiopod 7 ischium is not differentiated, and the ridge on merus is smaller, although distinctly visible. On pleopod 1 endopodite, the peculiar shape of the row of setae is already the same as in the adult males.

Remarks

Examination of the type series of Circoniscus gaigei revealed that these specimens belong to a different species than the specimens determined as C. gaigei by all subsequent authors. The next nominal species that with certainty is conspecific with the present material is Parcirconiscus ornatus Verhoeff, 1941 , according to the structure of male pereiopod 7.

The pleopod 1 endopodite of a male syntype is somewhat different from the other material: the basal portion (before the spermatic furrow begins) is distally constricted, so that there is a narrow zone in the middle and the distal part of the endopodite is broader than this narrow zone. This is here regarded as an artefact.

The description of C. amazonicus does not specify the differences from other species, and the figures are not sufficiently detailed. Male characters and maxilliped are identical to those of C. ornatus ; after reexamination of the paratypes, C. amazonicus is regarded as a synonym of C. ornatus .

In total, 466 specimens were examined, and this allowed the description some intraspecific variation as well as the characters of immature males.

Ecology

Warburg et al. (1997) in a central Amazonian floodplain (3°02′ S, 60°17′ W) made some ecological observations on a species of Circoniscus , which they refer to as C. gaigei . According to the body size (up to 7 mm) and the known distribution, these animals probably belong to C. ornatus . Eight specimens were found per square metre. During the inundation, the animals migrated into the canopies, where they were found under bark and in bromeliads. The gut contained detritus, root fragments, leaf litter, bark, moss, fresh leaves, spicules of freshwater sponges, a few algae, and hyphae and spores of fungi (Map Fig. 203 ).

Geographical distribution

Guyana ( Pearse, 1917), Peru ( Schmalfuss, 1980), and northern half of Brazil ( Souza & Lemos de Castro, 1991). (Map Fig. 216 )

Figures

Figure 203. Geographical distribution of Circoniscus gaigei (1), Ci. hirsutus (2), Ci. incisus (3), and Ci. intermedius (4).

Figure 209. Circoniscus ornatus (Verhoeff, 1941): ♂, 10.6 × 5.0 mm, cephalothorax 2.57 mm wide, habitus lateral, pleon dorsal; ♀, with marsupium 9.6 × 5.0 mm, cephalothorax 2.66 mm wide, cephalothorax lateral, dorsal, frontal, pigment omitted (Peru, Panguana, ‘Caña brava’, leg. Hanagarth, 2 July 1975, SMNS).

Figure 210. Circoniscus ornatus (Verhoeff, 1941): ♂, 3.8 mm wide, mouthparts, first antenna, second antenna (Peru, Department Huanuco, Rio Yuyapichis, 9°37′ S, 74°56′ W, altitude 260 m, September 1981, cCS 137).

Figure 211. Circoniscus ornatus (Verhoeff, 1941): ♂, 11 × 5.0 mm, cephalothorax 2.71 mm wide, pereiopods 1–3 (Peru, Panguana, leg. Hanagarth, ‘87.88 A 3.4. 16.11.75 Yar’, cCS 412).

Figure 212. Circoniscus ornatus (Verhoeff, 1941): ♂, 11 × 5.0 mm, cephalothorax 2.71 mm wide, pereiopods 4–6, pereiopod 4 dactylus caudal, uropod ventral (Peru, Panguana, leg. Hanagarth, ‘87.88 A 3.4. 16.11.75 Yar’, cCS 412).

Figure 213. Circoniscus ornatus (Verhoeff, 1941): ♂, 11 × 5.0 mm, cephalothorax 2.71 mm wide, pereiopod 7 frontal and caudal, second antenna, uropod dorsal (Peru, Panguana, leg. Hanagarth, ‘87.88 A 3.4. 16.11.75 Yar’, cCS 412).

Figure 214. Circoniscus ornatus (Verhoeff, 1941): ♂, 3.8 mm, sternite 7, pleopod 1 (Peru, Department Huanuco, Rio Yuyapichis, 9°37′ S, 74°56′ W, altitude 260 m, September 1981, cCS 137).

Figure 215. Circoniscus ornatus (Verhoeff, 1941): ♂, 3.8 mm, pleopods 2–5 (Peru, Department Huanuco, Rio Yuyapichis, 9°37′ S, 74°56′ W, altitude 260 m, September 1981, cCS 137).

Figure 216. Geographical distribution of Circoniscus ornatus; circles, material examined; squares, literature data (under the name C. gaigei).