DECAPODA LATREILLE, 1802

Jaume, Damià & Bréhier, Franck, 2005, A new species of Typhlatya (Crustacea: Decapoda: Atyidae) from anchialine caves on the French Mediterranean coast, Zoological Journal of the Linnean Society 144 (3), pp. 387-414 : 390-410

ORDER DECAPODA LATREILLE, 1802 SUBORDER PLEOCYEMATA BURKENROAD, 1963 INFRAORDER CARIDEA DANA, 1852

SUPERFAMILY ATYOIDEA DE HAAN, 1849 FAMILY ATYIDAE DE HAAN, 1849 SUBFAMILY TYPHLATYINAE HOLTHUIS, 1986 GENUS TYPHLATYA CREASER, 1936 TYPHLATYA ARFEAE SP. NOV.

Material examined

Résurgence de Font Estramar (Salses-le-château; Pyrénées-orientales, France).

condition for the cave ( Stock, Illife & Williams, 1986; Sket, 1996). Grotte des Fées de Leucate is therefore the first anchialine cave recorded in metropolitan France. Similar anchialine habitats on the inner shore of coastal lagoons have been reported from the Dominican Republic ( Jaume & Wagner, 1998) and Mallorca ( Encinas, 1983).

Font Estramar differs dramatically from Grotte des Fées de Leucate by its low salinity, its important outflow, and its lack of obvious stratification in the water column. Nevertheless, it can also be considered an anchialine habitat according to Sket (1996), who contended that any subterranean habitat where continental and marine waters and/or faunas may influence each other should be considered anchialine.

Typhlatya arfeae sp. nov. seems to be restricted to anchialine caves. Numerous ordinary freshwater caves belonging to the Corbières d’Opoul karstic system and located near the two caves inhabited by Typhlatya have been intensively surveyed for the prawn without any success (e.g. Gourg de l’Antre, Grotte du Presbytère, Résurgence du Mas d’En Caraman, Gouffre de Paziols, Barrenc de Villarzel, Grotte d’Allens, and Gouffre de la Tirounère). The distribution of the species seems also to be very localized, as it has not been recorded in two additional anchialine Holotype: specimen, sex unknown, body length 17.85 mm ( MNHN no. 15773)

Paratypes: 11 specimens, sex unknown; body length (in mm): 11.40, 16.85, 9.90, 11.45, 16.55, 12.25, 12.85, 15.20, 15.60, 14.00 and 12.25 mm ( MNHN no. 15774). Collected by Franck Bréhier, 17 April 2003 .

Grotte des Fées de Leucate ( Leucate ; Aude, France). Two specimens, body length 17.30 and 16.30 mm ( MNHN no. 15775). Collected by Franck Bréhier, 18 April 2003 .

Comparative material examined

Typhlatya miravetensis Sanz & Platvoet, 1995 : three specimens, sex unknown, from type locality, deposited at the Department of Ecology and Microbiology, University of Valencia, Spain.

Typhlatya cf. monae Chace, 1954 : Pozimán Cadena ( Oviedo ; Pedernales, Dominican Republic). Three specimens, sex unknown, deposited at IMEDEA. Collected by Damià Jaume, 8 November 1999.

Troglocaris inermis Fage, 1937 : Gouffre des Cent Fonts (Causse de la Selle; Hérault, France). Three specimens, sex unknown, deposited at F. Bréhier’s personal collection. Collected by Franck Bréhier, 31 May 2002.

Diagnosis

Eyes lacking pigment. Rostrum small, pointed, not extending beyond eyestalk and hardly beyond insertion of first peduncle segment of antennule. Sixth pleonite about 1.6 times longer than fifth pleonite. Antennulary stylocerite not reaching distal margin of first peduncle segment. Flagellar lobule of exopod of first maxilliped well developed and delimited from remainder of exopod. Armature along medial margin of dactylus of fifth pereiopod consisting of 19–28 spines, each with row of tightly set denticles on one side, and row of long pinnules on other side and dorsally; spine series ending distally with two longer and stouter spines with ornamentation reduced to few marginal denticles along one side only. Exopod of fifth pereiopod well developed, attaining ischiomeral articulation of endopod. Telson 2.0–2.3 times longer than wide, with 12 terminal spines.

Description

Body up to 17.85 mm long, unpigmented (white when alive), with completely regressed eyes. Rostrum small and variably pointed (compare Figs 3A , 4B and 5 ), subtriangular in cross-section, triangular in dorsal aspect ( Fig. 4A ), lacking teeth and rostral ridge; sometimes with 1–2 tiny setae on ventral rim (see Fig. 3A ). Rostrum hardly extending beyond insertion of first peduncle segment of antennule, in general shorter than eyestalks, but exceptionally reaching tip of eyestalk in some smaller specimens ( Fig. 3A ).

Carapace ( Fig. 3A ) rounded, 1.6 times longer than high, lacking spines or ridges; antennal and pterygostomial angles rounded, former hardly produced, not reaching tip of rostrum ( Fig. 4A, B ); posterolateral margins of carapace hardly extended posteriorly over first abdominal somite. Premarginal posterodorsal transverse suture scarcely developed; hepatic-branchiocardiac groove not observed.

Lateral body wall of fourth to eighth thoracomeres (corresponding to thoracomeres bearing first to fifth pereiopods) with one phyllobranchiate pleurobranch on each side, those on eighth thoracomere reduced (see Figs 3C , 13F , 15A ). Sternite of eighth thoracomere with posterior margin weakly produced anteriorly into triangular process with subterminal tuft of setules ( Fig. 4C ); process not extending beyond insertion of fifth pereiopod.

Pleon ( Fig. 3A ) with intercalary dorsal sclerite between carapace and first pleonite; Pleurae of first five pleonites rounded. Sixth pleonite about 1.62 times longer than fifth, with posterolateral lobe on each side; lobe with tiny denticle as in Figure 3B . Posterior margin of sternite of sixth pleonite projecting mediodistally into narrow triangular process bearing subdistal setule on rounded tip ( Fig. 18A ); process probably homologous with the preanal plate of T. galapagensis , Stygiocaris stylifera Holthuis, 1960 and Antecaridina lauensis (Edmondson, 1935) (see Monod & Cals, 1970: 97, figs 60–62), although in the new species, in T. miravetensis and in T. rogersi (and apparently also in T. mitchelli and T. campechae ; see Hobbs & Hobbs, 1976: 2, 6) this process is incorporated into the sternite and does not appear as a separate sclerotized plate. Anus positioned on posterior margin of sixth pleonite, just below insertion of telson ( Fig. 18A ).

Eyestalks ellipsoid, about 1.6 times longer than wide, with reduced area of thin cuticle at distolateral corner ( Fig. 4B ). Conical frontal process present between insertion of eyestalks and insertion of antennules ( Fig. 4A ). Paired soft finger-like processes inserted laterodorsally, adjacent to insertion of antennules, and apparently functioning to lock eyestalks laterally ( Fig. 4A ); process homologous with two processes, beneath the eyes, placed above the dorsal part of the antennulary praecoxa of T. galapagensis (see Monod & Cals, 1970: 73, fig. 23). At least in the new species this process is an integumental outgrowth of the body wall and does not form part of the antennule, as supposed by Monod & Cals (1970).

Antennule with 3-segmented peduncle reaching transverse suture line (= diaeresis) on antennal scaphocerite (see Fig. 6A ). Length ratio of peduncular segments 1–3 measured along medial margin approximately 0.41: 0.29: 0.30. Dorsodistal margin of first and second peduncular segments each with setae inserted on biarticulate socle, remaining setation as in Figure 6A ; first segment with stylocerite extending 82% length of segment; third segment with rounded process dorsodistally, apparently articulating with segment; process homologous with calcified plate mentioned in same position in T. galapagensis (see Monod & Cals, 1970: 73, fig. 23). Outer flagellum ( Fig. 6C ) with aesthetascs on ventral surface of proximal annuli, distributed as figured; basal portion of aesthetascs with transverse constrictions giving a segmented appearance ( Fig. 6D ). Inner flagellum lacking aesthetascs ( Fig. 6B ).

Antenna with 5-segmented peduncle; first segment (coxa) with recurved, finger-like soft process on ventrolateral surface ( Fig. 7C ); process tentatively homologous with coxal orifice placed on a membranous outgrowth of T. galapagensis (see Monod & Cals, 1970: 75, fig. 24). Second segment (basis) with two soft finger-like processes dorsolaterally ( Fig. 7A, C ), and acute tooth on ventromedial corner extending slightly beyond distal margin of third peduncular segment; outlet of antennary gland visible as soft conical process with terminal pore, located behind tooth. Third segment with single seta on distolateral corner. Fourth peduncular segment inserted on dorsomedial surface of preceding segment, with row of stout plumose setae, each on biarticulate socle, along distal and distolateral margins ( Fig. 7B, C ). Fifth segment elongate, about 2.2 times longer than wide, subrectangular, inserted dorsodistally on preceding segment, with cluster of smooth setae at distolateral corner. Scaphocerite inserted ventrolaterally on second peduncular segment, about 2.2 times longer than wide, with straight medial margin ending in pointed process; transverse integumental suture line (= diaeresis) extending from insertion of pointed process to about midway along scaphocerite. Outer margin of scaphocerite convex, distal margin evenly rounded; both margins fringed with plumose setae with transverse endocuticular interruptions giving a segmented appearance ( Fig. 4A ). Flagellum multiannulate, with proximal annuli incompletely separated ( Fig. 4B ).

Labrum (not figured) globular, constricted proximally, with setulose free posterodistal margin; two lateral and one frontal pointed process on constricted proximal part. Labium ( Fig. 12G ) deeply incised, V-shaped, each lobe (= paragnath) expanded distally, massive, ornamented with densely set setules along medial margin and carrying single smooth seta distolaterally on posterior surface.

Mandibles asymmetrical, lacking palp and lacinia mobilis, with sparsely set short plumose setae on surface of proximal part of coxal gnathobase ( Fig. 8A ). Left mandible ( Fig. 8A ) with incisor bearing three superimposed triangular teeth at anterodistal corner and blunt, truncate tooth at posterodistal corner. Setal row (= ‘ventral row of lifting spines’ of Fryer, 1977) consisting of four spinulose elements as in Figure 6B . Proximal portion of mandibular sinus with two superimposed marginal rows of slender plumose setae (= ‘dorsal row of lifting spines’ of Fryer, 1977), anteriormost row composed of shorter setae. Molar process large, with grinding surface strongly curved transversely and composed of parallel striated plates with tuberculate rim, each plate with short spinule distally ( Fig. 8C ); spinules progressively shorter, absent from plates on molar crown. Right mandible ( Fig. 8D ) with incisor narrower than on left counterpart, composed of six sharp triangular teeth ( Fig. 8E ). Setal row of five spinulose elements, more slender and less spinulose than on left mandible. Two superimposed rows of setae on mandibular sinus composed of fewer, and stiffer, setae than on left mandible ( Fig. 8F ). Molar process similar to left counterpart, but proximal margin of grinding plates with short dendriform spinules progressively shorter, absent from plates on molar crown ( Fig. 8G ); presence of such spinules on left mandible unconfirmed.

Maxillule ( Fig. 9A- D ) lacking expressed segmentation; tentatively interpreted as comprising coxa with broad, foliaceous endite (= ‘proximal lobe’ of Fryer, 1977), and two lobes representing the basis with basal endite (= ‘distal lobe’ of Fryer, 1977), and the endopod. Coxal endite pointed distally, setulose, with armature consisting of two superimposed rows of setae along medial margin; setae disposed in middle portion of anterior row stiff and with truncate tip ( Fig. 9C ), corresponding to the ‘fine funnelling setae of proximal endite’ of Fryer (1977). Two roughly parallel clusters of short setae on posterior surface of lobe; those comprising middle cluster with brush-like tips ( Fig. 9B ; setae probably homologous with the ‘lifting spines of the proximal endite’ of Fryer, 1977: fig. 78). Basal endite spatulate; distal half of medial margin with two parallel rows of stout conical spines with rounded tubercles ( Fig. 9D ); remaining armature on margin and on lateral surface of endite as figured. Endopodal lobe finger-like, with four subdistal setae.

Maxilla ( Fig. 10A ) phyllopodial, biramous, with basic structure corresponding tentatively to coxa with endite, basis with bilobed endite, reduced finger-like endopod and unsegmented exopod (= scaphognathite). Intersegmental articulations not expressed except partially between coxa and basis. Coxal endite (= ‘proximal endite’ of Fryer, 1977) with marginal comb row of long setae each swollen proximally; proximal and distal setae of comb row plumose, others rigid and apparently smooth; posterior surface of endite with row of about nine rigid setae each bipinnate distally; anterior surface of endite with cluster of heterogeneous setae (some plumose proximally but smooth distally, some fully plumose, some bipinnate distally, and others apparently completely smooth) arranged as in Figure 10B . Basis indistinct, with three plumose setae, one on medial margin, two on posteromedial surface of segment.

Proximal endite lobe (= ‘teaseling lobe’ of Fryer, 1977) with proximal margin slightly convex, medial margin straight, and distal margin oblique, not reaching distal margin of distal endite lobe. Posterior surface of lobe unarmed, anterior surface densely covered with rigid setae each unipectinate distally ( Fig. 10E ), arranged in parallel oblique rows ( Fig. 10C ); medial margin of lobe with sparsely set, smooth setae with rounded tips ( Fig. 10F ) mixed with typical unipectinate setae; row of slender setae with bipinnate tips ( Fig. 10D ) lying close and parallel to insertion of endite on anterior surface of segment. Distal endite lobe (= ‘distal endite’ of Fryer, 1977) spatulate, not extending beyond distal margin of scaphognathite, with heterogeneous array of armature elements consisting of plumose setae with smooth distal part, plumose setae with unipectinate distal part, smooth setae with rounded tip, and denticulate spines (as Fig. 10G ); several additional plumose setae located distomarginally on anterior surface of lobe.

Scaphognathite (= exopod) inserted on lateral margin of basis, distal lobe truncate, proximal lobe (= ‘caridean lobe’) well developed; margins fringed with plumose setae, those on distal margin of distal lobe longer and with several transverse endocuticular interruptions giving a segmented appearance. Endopod (= palp sensu Monod & Cals, 1970) extending to middle of distal lobe of scaphognathite, smooth except for three minute plumose setae inserted proximally on outer margin.

First maxilliped ( Fig. 11A ) phyllopodial, biramous, with coxa, basis, exopod and endopod indistinctly separated. Coxa with rounded endite bearing complex armature array comprising two marginal rows of long setae ( Fig. 11F ), one row of smooth geniculate setae with denticulate tips ( Fig. 11G ), and one of plumose setae with smooth tips; numerous short plumose setae each with smooth distal part set sparsely on anterior surface of endite, plus three setae with denticulate tips on anterior surface near distomedial margin. Coxal epipodite short, conical, with short smooth seta on tip instead of lamelliform podobranch apparently present in homologous position in T. iliffei (see Hart & Manning, 1981: fig. 38).

Basis indistinct, bearing row of about six long plumose setae, each with smooth distal part, on anterior surface, and row of about 14 shorter setae on posterior surface. Basal endite elongate, subrectangular, with complex armature comprising plumose setae with smooth distal portion and pointed tips, same type of setae but with rounded tips, short smooth setae with rounded tips ( Fig. 11D ), and plumose setae with denticulate tips ( Fig. 11E ); medial margin of endite with row of tightly set, rigid plumose setae displaying transverse lamellar expansions distally ( Fig. 11B, C ).

Exopod subrectangular, with distomedial corner produced into elongate process (‘flagellar lobule’ of Hobbs & Hobbs, 1976) extending about 46% of total length of segment. Lateral and distal margins of segment fringed with plumose setae; inner margin and margins of flagellar lobule with plumose setae each smooth distally. Anterior surface of segment with sparsely set plumose setae with smooth distal parts and several short smooth setae distributed as figured. Endopod reaching distal margin of basal endite, roughly triangular; inner (= medial) margin with row of plumose setae with smooth distal part, single similar seta on tip, and two tiny smooth setae on proximal part of outer (= lateral) margin.

Second maxilliped ( Fig. 12A ) stenopodial with expanded dactylus. Coxa unarmed, with podobranch reaching distal margin of ischium, and no trace of epipod. Basis and ischium almost completely fused, former slightly shorter, with sparsely set plumose setae with smooth distal portion along both margins and on anterior surface of segment, proximalmost seta on medial margin enlarged. Exopod elongate and slender, bowed, with plumose setae with smooth distal part along both margins of proximal part of segment; middle part of segment naked; distal part with plumose setae along both margins, setae with transverse endocuticular interruptions giving a segmented appearance; two short smooth setae on anterior surface of segment as figured.

Ischium with row of heterogeneous setae along medial margin (some plumose, others with denticulate tips as in Fig. 12B ). Merus about as long as ischium, but more slender, with row of plumose setae with smooth distal parts along medial margin. Carpus half length of merus, with digitiform process with microtuberculate ornamentation distally, on anteromedial surface; armature of segment reduced to single plumose seta with smooth distal part positioned subdistally on lateral margin. Propodus with expanded distal margin covered with smooth rigid setae, denticulate setae, and long plumose setae with denticulate distal parts and rounded tips ( Fig. 12C ); latter setae with subdistal pinnules stouter than rest.

Dactylus arising on medial margin of preceding segment and completely incorporated into it except for expression of vestige of intersegmental articulation on posterior surface; dactylus locked into flexed position by rounded process on carpus. Segment falcate, with smooth convex medial (but anatomically lateral) margin and slightly concave lateral (but anatomically medial) margin. Slit connected with duct present proximally on both anterior and posterior sides of segment. Anteromedial surface of segment ( Fig. 12D ) with smooth rigid setae, long plumose setae with smooth distal part, and single plumose seta distally. Medial margin of segment with row of tightly set, pectinate spines as in Figure 12E, F .

Third maxilliped ( Fig. 13A ) stenopodial, with small phyllobranchiate arthrobranch (i.e. associated with arthrodial membrane between coxa and body). Coxa with transverse row of plumose setae on inner margin and cluster of setae on distomedial corner; epipod bifurcate, posterior branch slender, not extending beyond coxa distally, with subdistal notch; anterior branch short and roughly conical, unarmed. Basis partially fused to ischiomerus, short, with row of unequal setae along medial margin. Exopod unsegmented, long and slender, bowed, extending beyond distal margin of ischiomerus; armature as described for preceding limb. Relative length of ischiomerus, carpus and propodus as shown in Figure 14 . Ischiomerus somewhat bowed, about six times longer than wide, with sparsely set short setae along both margins.

Carpus with 6–7 transverse rows of short bipectinate spines on medial surface of segment ( Fig. 13B ); row of smooth setae along distal margin. Propodus with heterogeneous array of transverse rows of spines on medial surface of segment, as follows: six rows of short bipinnate spines with expanded hyaline tips ( Fig. 13C ; cochlear setae of Monod & Cals, 1970; ‘distally spatulate setae’ of Hobbs & Hobbs, 1976) on proximal half of segment; four rows of spines with serrate triangular denticles along one margin only and with spinulose tips ( Fig. 13D ) located adjacent to preceding rows of spines; and about 12 smooth, conical spines ( Fig. 13E ) along distal part of segment; latter spines indistinguishable from larger terminal spine, interpretable as dactylus.

First pereiopod ( Fig. 13F ) chelate, with tip of propodus and dactylus covered with tuft of heterogeneous spines and setae (similar to those on second pereiopod, described in detail below and Fig. 15B- G ). Coxa, basis and exopod as in third maxilliped except for uniramous coxal epipodite (nevertheless similar to posterior branch of third maxilliped), presence of 2–4 long pinnate coxal setae (‘setobranchs’) on small outgrowth near origin of epipodite, and basis completely separated from ischium. Ischium completely separate from and slightly shorter than merus, both segments bearing few short smooth setae on both margins. Carpus with protruding conical outgrowth located about two-thirds distance along lateral margin; several smooth setae on outgrowth and margins of segment as figured. Chela (propodus + dactylus) slender, about 2.7 times longer than wide, with dactylar (= outer) process clearly extending beyond tip of propodal (= inner) process. Relative length of ischium + merus, carpus and propodus as in Figure 14 .

Second pereiopod ( Fig. 15A ) chelate, similar to preceding limb but more elongate due to ischium, merus and carpus proportionally longer (see Fig. 14 ). Exopod proportionally shorter, reaching distal margin of merus only (exopod reaching almost to conical lateral process on propodus in preceding limb; nevertheless, both exopods about equal in absolute length). Three ‘setobranch’ setae present on coxa. Chela similar to preceding limb both in size and armature, with terminal tuft of setae on dactylar process composed of heterogeneous array of spines and setae, as follows: Four stout sigmoid spines mid-ventrally, each with expanded tip and with transverse lamellar processes along posterior margin ( Fig. 15B, C ); spines apparently lacking internal canal described by Monod & Cals (1970: 67, fig. 6) for Typhlatya galapagensis . Sigmoid spines partially hidden by several rows of setae evolving progressively in form from innermost to outermost rows from coarsely serrate ( Fig. 15D ) to finely serrate scrapers ( Fig. 15E ), flexible finely unipinnate setae ( Fig. 15F ), and finally flexible setae with terminal brush ( Fig. 15G ). Terminal tuft on propodal process similar to that on dactylus but lacking sigmoid spines.

Third pereiopod ( Fig. 16A ) long and slender, stenopodial, with coxa, basis and exopod as in preceding limb; tip of exopod reaching about two-thirds of merus. Ischium incompletely separated from merus, about 4.7 times longer than wide, with one spine on medial margin. Merus with two spines on medial margin. Carpus lacking spines. Propodus with row of about 15 small spines along medial margin. Relative lengths of ischiomerus, carpus and propodus as in Figure 14 . Dactylus slender, with eight short, stout smooth spines on medial margin ( Fig. 16B ); spines progressively longer towards distal part of dactylus. Unguis smooth, with faint transverse endocuticular interruption proximally.

Fourth pereiopod ( Fig. 16C ) as for preceding limb except for relatively shorter ischiomerus and carpus (see Fig. 14 ), and for slight differences in number of armature elements, as follows: one additional medial spine present subdistally on merus, and 7–9 spines along medial margin of dactylus ( Fig. 16D ).

Fifth pereiopod ( Fig. 9E, F ) as for two preceding limbs except for relative length of ischiomerus, carpus and propodus (see Fig. 14 ), absence of coxal epipodite, presence of only two coxal ‘setobranch’ setae instead of three, only one spine on inner margin of merus, shorter exopod (as long as ischium only), and armature of medial margin of dactylus, consisting of series (grooming comb?) of about 19–28 similar spines, denticulate along one side, pinnate on other, and with additional row of pinnules dorsally; two additional, longer and stouter spines positioned distal to series, with ornamentation reduced to few marginal denticles on one side only (see Fig. 9F ).

Pleopods 1–5 biramous. Pleopod 1 somewhat shorter than pleopod 2, others decreasing progressively in length from 2 to 5. Protopods with evidence of subdivision (into coxal segment?) proximally, partially fused to basis anteromedially ( Fig. 17C ); protopod of pleopod 5 with row of smooth setae along lateral margin ( Fig. 17F ), protopods of pleopods 1–4 with setation reduced to two short setae on distolateral margin ( Fig. 17A, D ). Rami of pleopods unequal, exopod longer than endopod, both with marginal setation consisting of plumose setae with transverse endocuticular interruptions giving a segmented appearance. Endopod of all pleopods except first with slender appendix interna with cluster of denticulate retinacles on oblique tip ( Fig. 17E ); no trace of appendix masculina in any of the specimens studied. Exopod of first pleopod modified, expanded proximally and with distal portion elongate, but variable from hardly developed to well developed, as in Figure 17B ; short setae on segment as figured.

Uropods clearly longer than telson ( Fig. 18A ), with undivided protopod; exopod slightly longer than endopod. Most plumose setae along distal and medial margins of exopod and on margins of endopod, with transverse endocuticular interruptions giving a segmented appearance. Surface of both rami armed with mixed array of short setae, as in Figure 18A- C . Incomplete, sinuous transverse suture line (= diaeresis) on exopod, not reaching inner margin of segment, with short plumose seta and thorn-like spine inserted submarginally, and with row of smooth setules between insertion of spine and outer margin of segment ( Fig. 18B ). Endopod inserted dorsal to exopod on protopod.

Telson ( Figs 4D, E , 18A ) elongate, trapezoid, 2.0–2.3 times longer than wide, with two short smooth spines dorsolaterally on each side. Dorsal surface with four pairs of short smooth setae present along midline, plus several setules as in Figure 4D . Distal margin with six pairs of spines, outer two pairs smooth, rest spinulose. Outermost pair shortest, adjacent pair longer and stronger than rest; four inner pairs decreasing progressively in length towards midline ( Fig. 4E ).

Sexual dimorphism

None of the specimens analysed displayed evidence for appendix masculina on the second pleopods or carried eggs, thus preventing sex determination. Not one displayed the extra-setulation developed on the pleopods and on the margins of the epimeral plates of ovigerous females of some species, such as T. campechae ( Hobbs & Hobbs, 1976: fig. 3a, b; see also Juberthie-Jupeau, 1974). Likewise, none displayed an anteriorly vaulted, pointed extension (thelycum?) of the posterior margin of the sternite of the eighth thoracomere (= thoracomere carrying the fifth pereiopods; see Fig. 4C ); this structure seems to develop on (adult?) females in T. galapagensis (see Monod & Cals, 1970: fig. 58).

Etymology

The species name is based on the acronym ARFE, Association de Recherches de Font Estramar, and is dedicated to the members of this Association.

Figures

Figure 3. Typhlatya arfeae sp. nov., specimen 17.60 mm, sex unknown. A, habitus of 12.25 mm paratype. B, detail of posterolateral lobe of sixth pleonite. C, detail of left pleurobranchs on fifth to eighth thoracomeres (i.e. bearing pereiopods 2–5). Scale bar: A = 1.0 mm; B, C = 0.5 mm.

Figure 4. Typhlatya arfeae sp. nov., specimen 17.60 mm, sex unknown. A, anterior part of carapace, dorsal. B, detail of rostrum and eyestalk, lateral. C, detail of posterior margin of sternite of eighth thoracomere, ventral. D, telson, dorsal. E, detail of distal armature of telson, dorsal. Scale bar: A = 1.0 mm; B-D = 0.5 mm; E = 0.25 mm.

Figure 5. Typhlatya arfeae sp. nov., sex unknown. Variability in form of rostrum of different specimens (see also Figs 3A, 4B).

Figure 6. Typhlatya arfeae sp. nov., specimen 17.60 mm, sex unknown. A, proximal part of antennules and anterior part of cephalothorax with carapace removed, dorsal (eyestalks folded back into unnatural position). B, detail of proximal part of inner flagellum of antennule, dorsal. C, same for outer flagellum. D, detail of aesthetasc on outer flagellum. Scale bar: A-C = 0.50 mm; D = 0.125 mm.

Figure 7. Typhlatya arfeae sp. nov., specimen 17.60 mm, sex unknown. A, right antenna, dorsal. B, detail of three distal segments of peduncle and flagellum of latter, dorsal. C, left antenna, ventral. Scale bar = 0.05 mm.

Figure 8. Typhlatya arfeae sp. nov., specimen 17.60 mm, sex unknown. A, left mandible, anterior (= frontal) view. B, detail of element of setal row. C, detail of distal spinules on plates of grinding surface of molar. D, right mandible, posterior. E, detail of incisor and two distal elements of setal row on right mandible. F, detail of spinulose seta on proximal portion of mandibular sinus. G, detail of short dendriform spinules on proximal margin of plates of grinding surface of molar. Scale bar: A, D = 0.25 mm; B, C = 0.05 mm; E-G = 0.125 mm.

Figure 9. Typhlatya arfeae sp. nov., specimen 17.60 mm, sex unknown. A, left maxillule, posteromedial view. B, detail of seta with brush of pinnules on tip from middle cluster on posterior surface of coxal endite. C, detail of stiff seta with truncate tip on medial margin of coxal endite. D, detail of conical spine with tubercles on basal endite. E, right fifth pereiopod, lateral. F, detail of armature of dactylus of latter, medial. Scale bars: A = 0.25 mm; E = 0.5 mm; F = 0.05 mm; B-D not to scale.

Figure 10. Typhlatya arfeae sp. nov., specimen 17.60 mm, sex unknown, left maxilla. A, general view with proximal lobe of basal endite outlined only, posterior. B, detail of coxal endite showing armature on anterior surface only, posterior. C, detail of proximal lobe of basal endite with most armature elements on anterior surface removed and their origins indicated by circular scars, posterior. D-F, detail of armature elements on proximal lobe of basal endite. G, detail of denticulate spine on distal lobe of basal endite. D-G not to scale.

Figure 11. Typhlatya arfeae sp. nov., specimen 17.60 mm, sex unknown, left first maxilliped. A, anterior view with armature on medial margin of basal endite omitted. B, detail of armature. C, detail of rigid plumose seta with transverse lamellar expansions. D, detail of tip of smooth seta with rounded tip from lateral view, surface of basal endite. E, same from plumose seta with denticulate tip. F, detail of armature of coxal endite. G, detail of denticulate tip of geniculate setae of coxal endite. C-E and G not to scale.

Figure 12. Typhlatya arfeae sp. nov., specimen 17.60 mm, sex unknown, left second maxilliped. A, general view with dactylus outlined only, anterior. B, detail of denticulate tip of seta on medial margin of ischium. C, detail of denticulate tip of plumose seta on distal margin of propodus. D, detail of armature on anteromedial surface of dactylus, armature on medial margin omitted. E, detail of latter armature, with ornamentation of spines omitted except for two most proximal spines. F, detail of one of latter. G, left and proximal part of right paragnath, posterior (= ventral view). Scale bar: A, D, E = 0.125 mm; G = 0.25 mm; B, C and F not to scale.

Figure 13. Typhlatya arfeae sp. nov., specimen 17.60 mm, sex unknown. A, general view of right third maxilliped with corresponding arthrobranch, anteromedial. B, detail of bipectinate spine on medial surface of carpus. C-E, detail of several spines of heterogeneous array comprising medial armature of propodus. F, left first pereiopod and fourth thoracomere pleurobranch, anteromedial. B-E not to scale.

Figure 14. Typhlatya arfeae sp. nov., specimen 17.60 mm, sex unknown. Relative length of ischiomerus, carpus and propodus of third maxilliped (Mxp3) and pereiopods 1–5 (P1-P5).

Figure 15. Typhlatya arfeae sp. nov., specimen 17.60 mm, sex unknown, left second pereiopod and corresponding fifth thoracomere pleurobranch. A, general view, lateral. B, ventral view of dactylus, armature on right side partially omitted. C-G, sequence of different morphologies of armature elements of latter, progressing ventral-to-dorsalmost. Scale bar: A = 0.50 mm; B = 0.25 mm; C-G not to scale.

Figure 16. Typhlatya arfeae sp. nov., specimen 17.60 mm, sex unknown. A, left third pereiopod, lateral. B, detail of dactylus + unguis. C, right fourth pereiopod, medial. D, detail of dactylus + unguis. Scale bar: A, C = 0.50 mm; B, D = 0.25 mm.

Figure 17. Typhlatya arfeae sp. nov., specimen 17.60 mm, sex unknown. A, left first pleopod, anterior. B, detail of endopod, anterior. C, detail of proximal part of protopod, posterior. D, right second pleopod, anterior. E, detail of tip of appendix interna of latter, and of one of its distal retinacles, posterior. F, right fifth pleopod, anterior. Scale bar: A, C, D = 0.50 mm; B = 0.25 mm; C = 0.125 mm; E = 0.05 mm (with detail of retinacle not to scale).

Figure 18. Typhlatya arfeae sp. nov., specimen 17.60 mm, sex unknown. A, sixth pleonite, anus, uropods and telson, ventral view. B, detail of armature of diaeresis of left uropod, ventral. C, detail of armature on proximal portion of left uropodal endopod, ventral. Scale bar: A, C = 0.50 mm; B = 0.25 mm.