Typhlocirolana haouzensis, Boutin & Boulanouar & Coineau & Messouli, 2002

Boutin, C., Boulanouar, M., Coineau, N. & Messouli, M., 2002, Biodiversity in the stygobiontic cirolanids (Crustacea: Isopoda) from the Mediterranean Basin. I. A new species of Typhlocirolana in Morocco, taxonomic, ecological and biogeographic data, Journal of Natural History 36 (7), pp. 797-817 : 799-807

Typhlocirolana haouzensis n. sp.

Materials and methods

One male measuring 11 mm long and one female of 12 mm chosen from the largest specimens, were entirely dissected for study and drawing of appendages. Pieces were mounted into polyvinyl lactophenol on slides; these slides remain in the collections of one of the authors (M. Boulanouar). A dozen adult males and females were examined and partly dissected for study of intraspeci®c morphological variation. All these specimens form the syntype series. They were collected at the type site ( Boutin and Boulanouar, 1984): a well located in the Marrakesh palm grove, a few kilometres from the city. They were collected using a baited trap ( Boutin and Boulanouar, 1983). Two males from the same site have been deposited at the Institut Scienti®que, Rabat and the MuseÂum National d’Histoire Naturelle, Paris.

Description

General aspect. Blind and unpigmented. Body smooth and clearly ventrally ¯attened. Thickness of the body, at the medio-dorsal line, hardly equivalent to half of the body width. Body shape regular (®gure 1) with pereionite margins parallel, regularly rounded anteriorly at the ®rst pereionite and the cephalon; free pleonites slightly narrower than pereionite 7. Pleotelson subtriangular and widened. Pereionites 2±4 of same length and shorter than following ones. Pereionites 5±7 increasing in length successively; body width equivalent to one-quarter of total length from anterior margin of cephalon to end of pleotelson, from dorsal observation. Female generally longer (12 mm) than males (rarely> 11 mm).

Clypeo-labral complex. Clypeo-labral complex (®gure 2) with lanceolate lamina frontalis erected in the basal part and dorsally pointed between the antennula base. Clypeus with a ¯at triangular shape and rounded tips; median part regularly rounded and moderately protruding, covering only the lamina frontalis base; lateral lobes of clypeus rounded and slightly deēcted anteriorly, left and right of the labrum base. Trapezoidal labrum with large base in contact with the clypeus, and two rounded angles limiting the small and concave base. This distal labrum margin with a regular line of some 30 small setae, as in other more primitive genera of cirolanids (e.g. in the Mediterranean troglobitic Metacirolana ponsi described by Jaume and Garcia, 1992).

Antennulae. Antennule short, hardly reaching half of pereionite 1 when applied on lateral margin of cephalon. The three peduncle segments increasingly longer (1.00, 1.20, 2.12). Flagellum slightly shorter than peduncle (®gure 3) with 8±10 segments (male and female), with few setae: simple setae, 11±16 aesthetascs (sensillae of hyaline lamina aspect considered chemoreceptors) in females, 12 ±17 in males. Terminal ¯agellum segment without aesthetasc; ®rst article generally without aesthetasc, other articles with one, two or three laminae. Observed chaetotaxic formulae in males (5number of aesthetascs on each segment from the basal one to the last one): 12222210, 022222210, 12222221 0 and 022322330; females: 02222210, 0112221120, 022223221 0 and 122232210.

Antennae. If completely stretched along the body, reaching the posterior edge of pereionite 4. Length of peduncular segments, from the basal to the ®fth proportional to 1.00, 1.31, 1.25, 2.90 and 3.75; the ®rst one glabrous or with a small seta (®gure 4); following segments with simple setae or pennate setae. Flagellum nearly 1.8 times longer than peduncle, with 31±39 segments (female) and 30±41 (male); no signi®cant diOEerence in the ¯agellum of male and female; segment length regularly decreasing from the base to the apex; proximal article twice as long as the others; all segments with seven to eight setae.

Mandibles. Mandibles consistent with the general description by Racovitza (1912: 231); pars incisiva with three strong teeth in right mandible (®gure 6) and four in left, one of which is perpendicular to the three others (®gure 7). Lacinia mobilis bearing 10±15 toothed spines. Left pars molaris provided with 19±24 strong short and regular spines in males and 22±27 in females; right one with 19±24 (males) and 22±24 (females) spines. First palp article smooth, second segment with 12±14 barbed setae and three to six simple setae, the distal ones being longer; last article exhibiting 13-16 barbed setae, the last one is the longest; this last article is the shortest; article length proportional to 2.0±2.2 and 1.0.

Maxillules. Maxillules are stout and strongly chitinized (®gure 8). Internal lobe bearing three strong and plumose setae (5megasetae), rarely four, and two small simple setae. Lateral lobe with 10 strong and conical teeth and three setae; teeth are slightly curved with rounded tip; setae unequal in length and in shape, two are delicately pectinated distally.

Maxillae. Maxillae simple. Outer lobe provided with four to six (rarely three) setae barbed on one side in the distal part. Inner lobe with ®ve to seven similar setae. Basal (5protopodial) endite with 9±12 setae of diOEerent lengths, delicately plumosed on the two sides and at the tip, one strong proximal plumose seta (megaseta). Propod with a short simple seta in the middle of distal margin.

Maxilliped. Basis curved and exhibiting a palp (endopod) of ®ve articles provided with setae and a well-developed endite with only one coupling hook (®gure 10). First palp segment always with one inner simple seta at apex; second article with four to seven setae on inner margin and three to four on outer margin; article 3 with 11±18 setae on inner margin and ®ve to eight on outer side; article 4 with 10±12 setae on inner margin and only three on outer one; distal article with 10±13 terminal setae and two to three setae on outer margin; all setae are simple except the most distal setae on the last article which has a tendency towards plumose setae. Endite always with four to ®ve long plumose setae (megasetae) (®gure 11).

Pereiopods. Pereiopod 1 haptorial, shorter and stronger than the others (®gure 12). Basis with a proximal palmate seta and one to two simple setulae on outer margin, a distal spine with an additional setula and three to four small setae on inner margin. Ischium with four setulae, three of which on inner margin, one distal near outer corner, and one distal spine similar to that of basis and located on inner distal angle. Merus with three distal setulae on outer angle and an important and diversi®ed armature on inner margin composed of three molariform spines, two short strong spines with additional seta and one long simple seta (®gure 13). This armature is constant and similar in male and female. The merus bears also one to two simple small setae in the middle of each side close to the median molariform spine. Carpus reduced, as well as chaetotaxy which comprises one distal spine, and one to two simple setae. Propodus well-developed: inner margin depressed with an armature of three medio-distal spines and a bunch of ®ve to six apical setae; two other setae at terminal angle on outer margin and two rows of four to ®ve setula (one on inner side and close to the spine row, one on outer side). Dactylus with few setae: one short and proximal on inner margin, four subdistal located on a transverse line which form the`dactylian organ’, and two distal spines and setae, one of which constitutes the dactylus claw (®gure 14).

Pereiopods 2±7 are ambulatory appendages. Similar to each other, provided with an abundant and diversi®ed chaetotaxy (®gures 15±21). Pereiopods 2 and 3 exhibit the enigmatic propodial organ in the male (®gures 15±17) which represents a remarkable secondary sexual character in T. haouzensis n. sp. These two pereiopods diOEer from the following ones by their chaetotaxy, mainly by palmate setae on outer margin of basis: six to eight setae on P2±P3 (®gures 15, 16), three or four on P4±P7 (®gures 18, 19): two proximal and one or two distal on P4±P5, and two to four on the middle part of P6±P7 basis margin. Length of pereiopods increases from P2 to P7 while width decreases; basis of P4±P5 stronger and wider than that of P2±P3 and P6±P7.

Pleopods. Pleopod chaetotaxy abundant as compared to species of closely related genera Turcolana and Marocolana .

Pleopods 1 similar in male and female, partly covering pleopods 2±5 (®gure 22). Protopodus rectangular, short, with a series of six (rarely seven) coupling hooks on subdistal inner margin, one small seta on outer distal angle (®gure 23). The two rami with only one article, endopod slightly longer than exopod. Endopod long, sub-rectangular, characterized by a straight inner margin, and with 14±18 distal plumose setae. Exopod oval-rounded, nearly twice as wide as endopod, with 23±26 (often 27 in female) setae of regularly increasing length: the longest are distal, the shortest are located on inner and outer margin of subdistal part of the plate which bears two to four very small marginal setulae.

Pleopod 2 of female similar to pleopod 1. Protopod generally with six spoonshaped coupling hooks and one plumose seta (®gure 24). Endopod straight on inner margin, with only 13 distal setae, and slightly shorter (80%) than exopod. The latter regularly oval, with 30±32 setae on distal margin and 12 thin setulae close to the base on outer margin. In males (®gure 25), protopod similar to female protopod with six coupling hooks and one outer setula. Exopod with outer margin straight, provided with 26 ±35 long distally plumose setae, a row of about 15 minute setulae at basal outer corner. Endopod shorter, linguiform and narrow, with ®ve to seven distal setae. Appendix masculina rooted at inner proximal part of endopod; resembling a sabre blade with the tip slightly curved towards outer side, thicker on inner curved margin and slightly grooved; twice longer than plate and longer than appendage apex.

Pleopod 3 (®gure 26): protopod shorter than in pleopods 2 and 3, with four to ®ve coupling hooks and two to three plumose setae. Exopod regularly oval, longer than in pleopods 1 and 2, with a clear transversal suture line which separates the distal part and its 22±28 plumose setae from the larger basal part, which bears only the row of setulae in the outer angle and one short seta at the distal inner corner, near the transversal suture. Endopod clearly shorter than exopod (two-thirds), with same general shape and formed by one glabrous segment. In contrast to other pleopod rami which are ¯at and well-chitinized, this endopod is ¯eshy, as in pleopods 4 and 5, with a thin and supple cuticle suggesting a respiratory function.

Pleopods 4 and 5 (®gures 27, 28): structure and general shape similar to that of pleopod 3, with exopod divided in two parts by an articulation and endopod ¯eshy and glabrous (with clear gill function). Sympod with only ®ve or six setose elements, three to ®ve of which are coupling hooks. Exopod with only six or seven distal setae on pleopod 4 and only four or ®ve setae on pleopod 5.

Uropods. Uropods elongate; chaetotaxic equipment abundant and diversi®ed. General morphology and proportions of the three articles characteristic of the species (®gure 29).

Sympod subtriangular due to the oblique orientation of inner margin which continues the basal margin. Outer margin as long as outer margin of exopod, with three spines always present in male and female, one on the margin (at two-thirds of the length) and two strong spines grouped at distal part. About 10 small and simple setae more or less on the same line near outer margin (®gure 29); six to nine plumose setae similar to those of inner margin of endopod and on the same line. Exopod styliform; though regularly slender from base to apex (maximum width scarcely reaching one-quarter of the length), width decreases at three-quarters of the length, marked with two strong spines on outer margin and one on inner margin accompanied by three or four plumose setae; outer margin with one or two small more proximal spines and two lines of six or seven small simple setae: 12±14 simple apical setae of diOEerent length.

Endopod roughly triangular, clearly wider than exopod; maximal width reaching one-third of length. It seems slightly longer than exopod owing to the oblique distal margin of the sympod. Length slightly shorter than the exopod length from apex to middle of base: median length of endopod595±96% exopod length. Relative widening of the two uropod rami is an important character because of its variation in diOEerent species but it is di cult to measure it accurately; in T. haouzensis , maximum width of endopod as measured perpendicularly to the longitudinal median axis, reaching 1.8 times maximum width of exopod (similarly measured). Endopod bearing 7±10 plumose setae on internal margin. Width abruptly decreasing at four- ®fths of the length, in the subdistal part, with one or, most often, two strong spines. Seven to 10 palmate setae near inner margin grouped by two or three in the proximal 1 mm); (31) detail of pleotelson apex.

part. Groups of two of these sensilla located near external margin in the proximal part, which has ®ve setae (®gure 29), and near outer spines with two other setae. Thirteen to 16 simple distal setae of diOEerent lengths inserted in an apical excavation.

Pleotelson. Pleotelson broadly triangular, with two slightly rounded basal corners (®gure 30). Length reaching scarcely one-sixth of total body length (cephalon and pleotelson included). Base slightly convex forward. Maximum width 5maximum length on median line. About 40 thin, simple setulae on dorsal surface, except near basal corners. Distal margin pointed, denticulate (with excavations more or less symmetrically, on the right and on the left (®gure 31) with one simple seta on each indentation exactly on or near margin; the latter setae (8±12) exhibit no sexual diOEerences.