Stammericaris trinacriae (Pesce, Galassi, Cottarelli, 1989)

Bruno, Maria Cristina, Cottarelli, Vezio, Hauffe, Heidi Christine, Rossi, Chiara, Obertegger, Ulrike, Grasso, Rosario & Spena, Maria Teresa, 2017, Morphological and molecular analyses of epikarstic Parastenocarididae (Copepoda: Harpacticoida) from two Sicilian caves, with description of a new Stammericaris, Zootaxa 4350 (2) : 261-272

Stammericaris trinacriae (Pesce, Galassi, Cottarelli, 1989)

( Figs. 2 , 6–9 , 13 , 14 )

Locality. Italy, Sicily, Palermo province, Entella Cave (cadastral number: Si Pa 328 ), from different rimstone pools.

Material examined. Twenty males, 10 of which completely dissected, each mounted on one slide labelled Stammericaris trinacriae , male (NHMUK 2017. 63 - 72, DIBAF), pool number 6, 23/X/2012; three males, dissected, mounted each on one slide labelled Stammericaris trinacriae male (NHMUK 2017. 73 -75), pool number 3, 23/X/2012; one male, undissected, mounted on one slide labelled Stammericaris trinacriae male (NHMUK 2017. 76), pool number 1, 23/X/2012; one male, undissected, mounted on one slide labelled Stammericaris trinacriae male (NHMUK 2017. 77), pool number 7, 23/X/2012; one female, dissected, mounted on one slide labelled Stammericaris trinacriae female (NHMUK 2017. 78), pool number 19, 05/I/2014; 10 females, five of which dissected, each mounted on one slide labelled Stammericaris trinacriae female (DIBAF) pool number 6, 23/X/2012; one female, undissected, mounted on one slide labelled Stammericaris trinacriae female (NHMUK 2017. 79), pool number 1, 23/X/2012; one female, dissected, mounted on one slide labelled Stammericaris trinacriae female (NHMUK 2017.80), pool number 8, 23/X/2012; one female, dissected, mounted on one slide labelled Stammericaris trinacriae female (NHMUK 2017. 81); 132 specimens preserved in 90% ethanol in vial labelled Stammericaris trinacriae , pool number 3, 27/XII/2012 (NHMUK 2017. 82-91); 24 specimens preserved in 90% ethanol in vial labelled Stammericaris trinacriae , pool number 15, 01/III/2014 (NHMUK 2017. 92-101); 10 specimens preserved in 90% ethanol in vial labelled Stammericaris trinacriae , pool number 15, 05/I/2014 (NHMUK 2017. 102 -111); three females (05/XII/2013, pool 15); two females and one male (05/IV/2014, pool 19) prepared for scanning electron microscopy, on two stubs (CIME). Remaining material (not examined): all remaining specimens (3146 males, 3718 females, 517 copepodites) from same locality, preserved in vials with 70% ethanol and glicerin (DIBAF). All material collected by RG and MTS. Male holotype and female paratype loaned from L. Pesce’s collection, University of L’Aquila (Italy).

Description. Male. Body unpigmented, nauplius eye absent. Total body length, measured from tip of rostrum to posterior margin of caudal rami (excluding caudal setae) from 366 to 438 µm, mean 411 µm (n = 10). Habitus ( Figs. 2B , 12C ) cylindrical and slender, without any demarcation between prosome and urosome; prosome to urosome ratio: 0.69. Free pedigerous somites without any lateral or dorsal expansions, all connected by welldeveloped arthrodial membranes. Integument weakly sclerotized, without cuticular pits, ornamented with sensilla on all somites except preanal one. Cephalothorax ( Figs. 2A , 12D ) and urosomites without cuticular windows ( Fig. 2B ). Cephalothorax ( Fig. 2B ) representing almost 15.7 % of total body length (measured from tip of rostrum to end of caudal ramus). Anal somite ( Figs. 6A, B ) with pair of large dorsal sensilla at base of anal operculum, pair of cuticular ventral pores (one pore on each side) near the insertion of caudal rami. Anal operculum ( Figs. 6A, B ) well-developed, with slightly concave distal margin. Anal sinus wide open, with spinular rows ( Fig. 6B ). Spermatophore ( Fig. 6C ) about 1.5 times as long as genital somite.

Caudal rami ( Figs. 6A, B , 13A ): longer than anal somite, approximately cylindrical, slightly divergent; length/ width ratio: 5.1, with distal pore between setae IV and V. Anterolateral accessory seta (I), and posterolateral seta (III) subequal in length, anterolateral seta (II) longer than seta I and III (length seta/length caudal ramus: 0.36); all three setae inserted together distally at 4/5 length of the caudal ramus. Outer terminal seta (IV) pinnate (length seta/ length caudal ramus: 1.29); inner terminal seta (V) apically pinnate, without fracture plane. Terminal accessory seta (VI) short (length seta/length caudal ramus: 0.40) and smooth. Dorsal seta (VII) articulate, inserted distally at 4/5 length of the caudal ramus as setae I–III.

Rostrum ( Fig. 6D ): small, triangular, almost reaching distal margin of first antennular segment, ornamented with two dorsal sensilla.

Antennule ( Figs. 6D, 6E , 12D ): prehensile, eight-segmented, pocket-knife type sensu Schminke (2010). First segment short with transversal row of spinules, second segment longest, with six setae, the longest seta uniplumose. Third segment with four distal bare setae; fourth segment reduced to a small sclerite with two short setae ( Fig. 6E ). Fifth segment enlarged, with inner protrusion, which is approximately conical and folded at the tip, carrying two small spiniform setae; distal tubercle with two equal setae and one large aesthetasc, restricted at midlength, reaching to half of eighth segment, one longer seta inserted at base of tubercle. Sixth segment bare, fused to previous one. Seventh segment bare, distal anterior corner protruding as a triangular, pointed apophysis. Eighth segment with seven setae and apical acrothek represented by two subequal setae and a slender shorter aesthetasc, approximately as long as segment. Armature formula: 1-[0], 2-[1 uniplumose + 5 bare], 3-[4 bare], 4-[2 bare], 5-[5 + ae], 6-[0], 7-[0], 8-[7 bare + (2 + ae)].

Antenna ( Figs. 6F , 12D ): coxa unarmed; allobasis with transverse row of spinules on inner margin. Exopod represented by a small segment, with very long pinnate apical seta. Endopod bearing two short lateral, one short subdistal, and four longer distal elements, two of them geniculate; all elements with long spinules near their insertions.

Labrum ( Fig. 7A ): large and rounded, with convex and smooth anterior surface, narrow cutting edge, cutting edge with apical row of slender denticles.

Mandible ( Fig. 7B ): coxal gnathobase bare, with pore, cutting edge with apical teeth and small supabical pinnate seta. One-segmented palp, with two distal setae of subequal length.

Maxillule ( Fig. 7C ): praecoxal arthrite with three distal, curved robust spines apically denticled, one subdistal curved seta, one distal spinule row. Coxal endite short, with one apical thin seta reaching to the end of arthrite. Basis cylindrical, with two distal bare setae of same length. Endopod and exopod absent (fused to basis without trace).

Maxilla ( Fig 7D ): syncoxa with two endites, proximal endite short, with one thin seta; distal endite cylindrical, longer, armed apically with one enlarged pinnate seta, two long bare setae; allobasis prolonged into apical pinnate claw; endopod represented by small segment fused at the base, with two long setae of equal length.

Maxilliped ( Fig. 7E ): prehensile. Syncoxa small and unarmed; basis slim and elongate with spinular row along inner margin; endopod represented by distally unipinnate claw.

P1 ( Figs. 7F , 12D, 12E ): with smooth and small intercoxal sclerite; basis armed with single slender seta on outer margin and a hook on the inner margin of basis; ornamented with transverse row of minute spinules at base of outer seta; transverse spinular row along distal margin on anterior surface, between exopod and endopod. Exopod three-segmented, slightly shorter than endopod, second segment shortest; exp-1 with thin and slightly curved pinnate seta on outer distal corner; exp-3 with two geniculate and one normal pinnate apical setae, and one subapical pinnate seta. Endopod two-segmented; enp-1 as long as the first two segments of the corresponding exopod, with two transversal rows of spinules on the outer margin, two spinules at 3/4 of the inner margin. Enp-2 thinner than enp-1 and as long as of enp-1, with longitudinal row of spinules on the outer margin and two spinules at 3/4 of the inner margin; long, geniculate pinnate seta, and shorter pinnate seta on apex.

P2 ( Fig. 7G ): with smooth and large intercoxal sclerite, twice as wide as long. Basis unarmed, with spinular row on outer margin. Exopod three-segmented, exp-1 with strong distolateral pinnate spine and transversal spinular row at of the outer margin ( Fig. 12D ); first and second segments of same length, exp-3 shortest; exp-3 armed with unipinnate subapical outer spine, apical unipinnate spine and bipinnate seta. Endopod one-segmented, about 1/3 the length of the corresponding exp-1, represented by cylindrical segment, with apical seta about as long as segment, and two apical short spinules about the length of apical spinule.

P3 ( Figs. 7H, 7I , 12F ): intercoxal sclerite taller than wide, trapezoidal, unornamented, and with slightly concave distal margin. Basis robust, with long, slender, smooth outer seta and outer row of transversal spinules, inner row of transversal spinules below endopod insertion. Endopod reduced to long thin seta. Exp-1 length/width ratio: 2.9; inner margin with conical proximal tubercle, and long, downward-pointed distal process. Exp-2 fused with exp-1 and prolonged into very long apophysis bent inwards, with blunt round tip, exp-2 and apophysis twice as long as exp-1. Distal thumb represented by thin and pointed segment, reaching to almost 1/2 of the apophysis.

P4 ( Fig. 7J ): intercoxal sclerite smaller than in P2 or P3, with concave, smooth distal margin. Basis armed with single slender seta on outer margin; ornamented with row of spinules at base of outer seta, and one short seta and two spinules of same length and slightly curved outwards aligned along inner margin. Exopod three-segmented, slender, all segments approximately of the same length; exp-1 slightly curved inwards, with distolateral pinnate spine; exp-3 armed with outer pinnate spine and long apical pinnate seta, spine length less than ¼of seta length. Endopod one-segmented, longer than corresponding exp-1, represented by a basal plate distally enlarged into an inner pointed protrusion ending in a fused spinule; a second spinule is inserted at half of the outer margin. The endopod extends on the distal outer corner into a long bipinnate process (fused seta).

P5 ( Figs. 7K , 13B ): fused to intercoxal sclerite, represented by two trapezoidal cuticular plates with innerdistal corner produced into short and thin pointed tip. Armature on free distal margin, from inner to outer: three bare setae of different length, outermost shortest, and long basipodal seta.

P6 ( Fig. 7K ): vestigial, fused into simple cuticular plate, unornamented and unarmed.

Female. Body length, excluding caudal setae, from 363 to 446 m, mean 391 m (n = 6); length of specimen in Fig. 1B : 454 m. Habitus as in Fig. 13C , ornamentation of somites, pigmentation, and lack of nauplius eye as in male, except genital and first urosomite fused into double-somite. Prosome/urosome ratio: 0.71. Genital doublesomite ( Fig. 8A ) without any trace of subdivision, longer than previous and following somites. Genital field ( Figs. 8A , 14D ) broader than tall, occupying anterior ventral half of genital double-somite; single genital aperture covered by fused vestigial sixth legs; median copulatory pore located medially at 1/3 of double-somite length. Anal somite and anal operculum as in male ( Fig. 14E ).

Caudal rami ( Figs. 8B , 14F ) shape similar to those of male but shorter, length/width ratio: 4.7. Ornamentation and armature similar to those in male but setae IV to VI proportionally shorter and seta VII proportionally longer; length seta IV/length caudal ramus: 0.54; length seta VI/length caudal ramus: 0.37, length seta VII/length caudal ramus: 0.49.

Rostrum, antenna, oral appendages ( Fig. 13D ), maxilliped as in male.

Antennule ( Fig. 8D ): seven-segmented, aesthetasc on fourth segment shorter than in male, reaching below end of seventh segment. First segment bare. Second segment longest. Apical acrothek represented by two setae of different length and slender aesthetasc, almost as long as aesthetasc on segment four. Armature formula: 1-[0], 2-[1 pinnate +3 bare], 3-[5bare], 4-[2 + ae], 5-[1], 6-[1], 7-[7 bare + (2 + ae)]. Several setae transformed, ending in a small hollow disk ( Fig. 13E ).

P1 ( Figs. 8E , 13F ): basis, ornamentation and armature as in male except with inner curved seta apically transformed, and pore near outer seta insertion; endopod and exopod similar in shape to the male, but endopod slightly longer than exopod.

P2 ( Figs. 8F , 14A ): coxa and basis as in male with spinular row on ventral side, near endopod insertion.

Ornamentation and armature of exopod as in male. Endopod similar in shape and ornamentation to that of the male, apical seta proportionally longer.

P3 ( Figs. 9A , 14B ): intercoxal sclerite taller than wide, with concave margin, smooth. Basis with outer seta and spinular row, and spinular row on ventral side, near endopod insertion ( Fig. 14B ); exopod two-segmented, segments of same length. Exp-1 ornamented with spinular row along outer margin, with distolateral pinnate spine; exp-2 with subapical outer pinnate spine and apical pinnate seta. Endopod ( Fig. 14B ) represented by a thin and pointed segment, with spinules along margin, 0.8 times as long as corresponding exp-1.

P4 ( Figs. 9B , 14C ): intercoxal sclerite, coxa, exopod as in male. Basis with spinular row on ventral side, near endopod insertion. Endopod represented by a thin cylindrical segment, ending in a pointed tip, pinnate in the distal half, slightly shorter than the corresponding exp-1.

P5 ( Figs. 8A , 14D ): fused to intercoxal sclerite, represented by two cuticular plates much longer and narrower than in the male, with proximal large pore and inner-distal corner produced into long and strong pointed tip. Armature on free distal margin, from inner to outer: three bare setae of different length, outermost shortest.

P6 ( Fig. 8A ): vestigial, fused into simple cuticular plate, covering gonopore, unornamented and unarmed.

Variability. Two females with transformed caudal rami ( Fig. 8C ): length/width ratio: ~3; armature modified as follows: seta I, II, III subequal and very short, seta IV transformed in a hooked spine, seta V massive, conical, and distally pinnate; setae VI and VII shortened.

Amended diagnosis of the genus Stammericaris Jakobi, 1972 . Male antennule 8-segmented and of the pocket-knife type. Basis P1 male with hook, with hook and seta, without armature (but see note below) near endopod insertion. Basis P1 female with small seta or without armature (but see note below). Endopod P3 female half as long as or shorter than first segment of corresponding exopod. Outer margin of P3 male exp-1 proximally and distally with group of several spinules, or spinules only proximally (in one case) or without spinules (one case); apophysis long with a rounded tip and slightly curved inwards, being twice as long as the thumb or even longer. Male P4 basis with an inner row of 1-4 curved spinules decreasing in size laterally; P4 male endopod a curved plate with a pointed inner tip carrying at its outer border two outgrowths, in most cases the distal one is a feathered or plain seta. Caudal rami cylindrical almost as long as anal somite, group of lateral setae located at end of rami.

Note: in all recently-described species the P1 basis of males and females is medially armed; it is very likely that this character was not noted in early descriptions.

Figures

FIGURE 1. Map of carbonatic and evaporitic rocks located in Sicily: A, Conza Cave; B, Molara Cave; C, Entella Cave.

FIGURE 2. A, Stammericaris destillans sp. nov.: A, male, habitus, lateral view; B, Stammericaris trinacriae (Pesce, Galassi and Cottarelli, 1988), male, habitus, lateral view. Scale bar: 50 micrometers.

FIGURE 6. Stammericaris trinacriae (Pesce, Galassi and Cottarelli 1988), male: A, anal somite, anal operculum and caudal rami, dorsal view; B, fourth and fifth urosomites, anal somite, anal operculum and caudal rami, ventral view; C, spermatophore; D, rostrum and antennule, dorsal view; E, antennule, disarticulated (antennular segments marked with roman numerals); F, antenna. Scale bar: 50 micrometers.

FIGURE 7. Stammericaris trinacriae (Pesce, Galassi and Cottarelli 1988), male: A, labrum; B, mandible; C, maxillule; D, maxilla; E, maxilliped; F, P 1; G, P 2; H, P 3; I, P 3, lateral view; J, P 4; K, P 5, P 6, first and second urosomites, ventral view. Scale bar: 50 micrometers.

FIGURE 8. Stammericaris trinacriae (Pesce, Galassi and Cottarelli 1988), female: A, first urosomite, P 5, P 6, genital doublesomite and genital field, ventral view; B, anal somite, anal operculum and caudal rami, dorsal view; C, caudal ramus, lateral view (variability); D, antennule; E, P 1; F, P 2. Scale bar: 50 micrometers.

FIGURE 9. Stammericaris trinacriae (Pesce, Galassi and Cottarelli 1988): A, female, P 3; B, female, P 4; C, male holotype, caudal ramus, lateral view; D, male holotype, antennule; E, male holotype, P 3; F, male holotype, P 4 basis and endopodite; G, female paratype, typical series, caudal ramus, lateral view; H, female paratype, typical series, P 3; I, female paratype, typical series, P 4 endopodite; J, female paratype, typical series, P 5. Scale bar: 50 micrometers.

FIGURE 12. Stammericaris destillans sp. nov.: A, female, P 4, P 5, genital field with attached spermatophore, ventral view; B, female, caudal ramus, outer view. Stammericaris trinacriae (Pesce, Galassi and Cottarelli 1988), male: C, habitus, lateral view; D, cephalothorax and first two pedigerous somites, antennule, antenna, P 1, P 2, lateral view. E, basis P 1, inner view; F, P 3, inner view.

FIGURE 13. Stammericaris trinacriae (Pesce, Galassi and Cottarelli 1988): A, male, caudal rami, lateral view; B, male, P 5. C, female, habitus, ventral view; D, female, mouth parts, ventral view.; E, A 1, transformed setae on fifth segment; F, female, basis P 1, anterior view.

FIGURE 14. Stammericaris trinacriae (Pesce, Galassi and Cottarelli 1988), female: A, P 2 endopod, lateral view; B, P 3 endopod, lateral view; C, P 4 endopod, lateral view; D, P 5 and genital field; E, anal somite and anal operculum, lateral view; F, caudal rami, lateral view.