Benthana araucariana, Lopes, 2003

Lopes, Paula Beatriz Araujo Elis Regina C., 2003, Three new species of Benthana Budde-Lund (Isopoda, ‘ Philosciidae’) from Brazil, Journal of Natural History 37, pp. 2425-2439 : 2433-2437

Benthana araucariana sp. nov.

(figures 32–44, 47, 49)

Type-material. H  , Brazil, RS, São Francisco de Paula (National Forest — FLONA 29 °42∞S, 50°39∞W), Araucaria Forest, one W, 25 September 1998 , collected in leaf litter by P. B. Araujo and G. Bond-Buckup ( MNRJ, 15242). P   : Brazil, RS: São Francisco de Paula ( FLONA, 29°42∞S, 50°39∞W), three WW, two XX, 25 September 1998 , P. B. Araujo and G. Bond-Buckup col. ( UFRGS 2931 P); (29°42∞S, 50°39∞W), four WW, three XX ovigerous, 18 September 1999 , E. R. C. Lopes col. ( UFRGS 2932 P); São Francisco de Paula (29°41∞S, 50°35∞W), two WW, two XX, 3 November 1998 , M. A. Azevedo and E. R. C. Lopes col. ( UFRGS 2933 P); (29°30∞S, 50°2∞W), one X, 6 November 1998 , E. R. C. Lopes col. ( UFRGS 2935 P); (29°17∞S, 50°16∞W), 12 WW, 14 XX, three XX ovigerous, 19 September 1999 , E. R. C. Lopes col. ( UFRGS 2937 P); (29°17∞S, 50°15∞W), three WW, four XX, 19 September 1999 , E. R. C. Lopes col. ( UFRGS 2938 P); São Francisco de Paula (Tainhas, 29°37∞S, 50°42∞W), four WW, four XX, five XX ovigerous, 6 November 1998 , E. R. C. Lopes col. ( UFRGS 2934 P); (29°32∞S, 50°40∞W), five WW, two XX, seven XX ovigerous, 26 November 1998 , E. R. C. Lopes col. ( UFRGS 2936 P). All collected in leaf litter in Araucaria Forest .

2434

P

.

B

.

Araujo

and

E

.

R

.

C

.

Lopes

F







32

–

38

.

Benthana

araucariana

sp

.

nov

.

(

32

)

Dorsal

view

of

male

(

holotype

)

.

(

33

)

Antennula

.

(

34

)

Antenna

.

(

35

)

Pleotelson

and

uropods

.

(

36

)

Maxilliped

.

(

37

)

Maxillula

.

(

38

)

Maxilla

.

Scales

:

(

32

,

34

,

35

)

=

1

mm

;

(

33

,

36

–

38

)

=

0.1

mm

.

Diagnosis. Antennule with 9+2 aesthetascs, exopod of pleopod 1 elongated, eyes with 24 ommatidia and coxal plate VII with two noduli laterales.

Description

Maximum length. Male 8.6 mm, female 8.9 mm.

Colour. Similar to that of B. trinodulata , except that the unpigmented regions of the pleon are larger on pleonite 1 (figure 32).

Cephalothorax. Eyes with 24 ommatidia.

Pereion. Tegument smooth and bright. Coxal plate VII has two noduli laterales (figure 49). Co-ordinates b /c and d/c of the noduli laterales (figure 47).

Pleon. Narrows abruptly in relation to the pereion; neopleura well-developed on segments 3–5. Pleotelson triangular with straight margins, with a groove on the distal third and rounded apex, reaching halfway down the protopodite of the uropods.

Appendages. Antennula tri-articulate, with the distal article having a series of nine aesthetascs at the distal half of the external margin and two apical aesthetascs (figure 33). Antenna when extended posteriorly, reaches the posterior margin of the fourth pereionite. Flagellum and fifth article of the peduncle of sub-equal length. Second flagellar article shorter than the other articles, which have similar lengths; apical organ one-third of the size of the distal article (figure 34). Mandible: similar to that of B. trinodulata , with two penicils on the incisor process and a tuft of at least ten plumose setae. Maxillula: medial endite with two apical penicils, no distal point; lateral endite with 4+6 teeth, five being pectinate (figure 37). Maxilla: external lobe with the distal-lateral margin narrowing; internal lobe covered with fine setae (figure 38). Maxilliped: endite with a long seta and two short teeth on the distal external margin, which has protuberances, dorsally bearing a short and robust seta (as in figure 10); apex of the palp with a tuft of short fine setae (figure 36). Pereiopods: with short tricorns on all articles and a hand-shaped apical seta on the carpus of pereiopod 1 (figure 43). Sexual differentiation: pereiopods 1–4 of the male with the carpus and merus bearing a set of fissured setae; ischium and merus of pereiopod 7 of the male of sub-equal length (figure 44); ischium of the females larger than the merus. Pleopods: exopod of pleopod 1 of the male cordiform, elongated (z: y ratio= 2.3), with a subapical dentiform expansion (figure 39); endopod with small apical spines (figure 40). Exopod of pleopod 2 distally elongated on the internal margin, carrying setae on the external margin; endopod distally tapered (figure 41). Exopod of pleopod 5 with four setae on the external lateral margin (figure 42). Uropod: insertion of the endopod and exopod at the same level; endopod exceeding half the length of the exopod (figure 35).

Etymology

The name refers to the region where this species occurs, the Brazilian Araucaria Forest.

Remarks

This species was collected on the Rio-Grandense Plateau (RS), at altitudes above 900 m. Benthana araucariana is similar to B. trinodulata because it has more than one nodulus lateralis on coxal plate VII, is of similar body colour, has similar antenna and uropods, has a similar number of aesthetascs on the antennula (9+2) and in having the insertion of the exopods and endopods of the uropods at similar levels. It can be differentiated by the elongated exopod of pleopod 1 of the male, two noduli laterales on coxal plate VII (three for the other species) and eyes with 24 ommatidia (20 in B. trinodulata ).