Simplicaris LETHAEA 2004, SP. NOV.
Creators: name: Galassi, Diana M. P.
name: Laurentiis, Paola De
Publisher: name: Zenodo
Year: 2004
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Maxillopoda
Harpacticoida
Parastenocarididae
Simplicaris

description: SIMPLICARIS LETHAEA SP. NOV.
Material examined and type locality. Male (holotype), female (paratype), completely dissected and mounted in polyvinyl lactophenol, deposited in the Natural History Museum, London (reg. no NHM.2004.48 holotype; NHM.2004.49 paratype). Other paratypes: 3 ♂♂, 1 ♀ deposited in the Natural History Museum, London. Other material: 3 ♂♂, 2 ♀♀ in the collection of D. Galassi (University of L’Aquila). The type specimens were collected from interstitial habitats of the Presciano Spring system (Capestrano, L’Aquila, central Italy), 150 cm below the spring bed, temperature 10.55∞C, electrical conductivity (25∞) 483 mS/cm, pH 7.28, dissolved oxygen 8.28 mg /L, sediment composed of gravel and coarse sand, 31.vii.1996, coordinates 42∞16¢05¢¢N, 13∞46¢56¢¢ E. One ♂ collected from interstitial habitat of the same spring, 150 cm below the spring bed, on the right side of the spring, temperature 11.88∞C, electrical conductivity (25∞) 489 mS/cm, pH 7.36, dissolved oxygen 8.42 mg /L, sediment composed of a large amount of particulate organic matter (13.63 mg /L), fine sand and silt, 28.vi.1996. One ♀ collected from interstitial habitat in the same spring system (Abate Spring), 150 cm below the spring bed, temperature 11.31∞C, electrical conductivity (25∞) 516 mS/cm, pH 7.36, dissolved oxygen 8.80 mg /L, sediment composed of fine sand, 18.ix.1996, altitude: 330 m a.s.l., coordinates 42∞16¢04¢¢N, 13∞47¢37¢¢E, coll. A. Marcheggiani, P. De Laurentiis & D. Galassi.
Description
Male. Total body length of the holotype, measured from tip of rostrum to posterior margin of caudal rami, 279 mm (range: 260–304 mm, with mean of 284 mm based on eight individuals). Body vermiform, slender (Fig. 1A). Integument without surface pits, only feebly sclerotized. Hyaline frills of cephalothorax, somites bearing P2–P4 and urosome smooth. Integumental windows, located dorsally, rounded on cephalic shield and elliptical on abdominal somites, excluding anal somite. Cephalothorax and both thoracic and abdominal somites with cuticular ornamentation apparently represented by reduced number of paired sensilla (Fig. 1A). Anal somite with paired sensilla on dorsal side only (Fig. 1B). Anal operculum rounded, not protruding beyond insertion line of caudal rami. Caudal rami with complete setal pattern (seven setae) (Fig. 1B). Anterolateral accessory seta (I), anterolateral seta (II) and posterolateral seta (III) inserted on distal third of ramus. Outer terminal seta (IV) short (length seta/length caudal ramus: 0.42–0.46) and naked, inner terminal seta (V) plumose and long (length seta/length caudal ramus: about 3); terminal accessory seta (VI) slightly longer than outer terminal seta; dorsal seta (VII) inserted dorsomedially on distal third of caudal ramus, longer than setae IV and VI (length seta/length caudal ramus: about 1). Fine spinules located on ventral distal margin of caudal rami. One pore located ventrolaterally to insertion of setae I- III.
Rostrum small, not defined at base; with two dorsal sensilla (Fig. 1A).
Antennule (Fig. 1C) elongate, 8-segmented. Segment 1 with one ventral spinule row. Segment 2 longest. Segment 4 represented by small U-shaped sclerite. Segment 5 largest, sclerotized. Segment 7 prolonged into an apophysis with rounded tip. Armature formula: 1-[0], 2-[5 bare + 1 unipinnate], 3-[3], 4-[0], 5-[3 + (1 + ae)], 6-[0], 7-[0], 8-[7 + acrothek]. Apical acrothek consisting of two setae of different length and a slender, short aesthetasc. Aesthetasc on segment 5 very large, reaching far beyond distal segment of antennule.
Antenna (Fig. 1D): coxa unarmed; allobasis with two transverse spinule rows on inner margin; exopod 1-segmented, well-defined at base, bearing one unipinnate spine; free endopod with inner spinule row, armature consisting of two outer spines, two apical spines, two apical geniculate setae and one apically serrate seta; a row of spinules at outer corner.
Mandible (Fig. 2A): coxal gnathobase elongate, cutting edge with two distally crenulate coarse teeth and row of smaller teeth; naked seta at dorsal corner. Mandibular palp uniramous, 1-segmented, with two apical setae.
Maxillule (Fig. 2B): praecoxal arthrite well developed, rectangular, with three strong curved spines accompanied by four tiny, bare setae; one anterior surface seta inserted on a sort of peduncle. Coxal endite with one seta. Basis with three apical setae. Exopod and endopod absent.
Maxilla (Fig. 2C): syncoxa with two endites. One setule inserted on proximal part of syncoxa. Proximal endite with one seta; distal endite with one naked and one distally crenulate setae, one flaccid seta subapically inserted. Allobasis drawn out into a strong claw, distally spinulose; endopod represented by two setae, subequal in length.
Maxilliped (Fig. 2D): very large, as long as leg 1; subchelate. Syncoxa small and unarmed; basis elongate and slender, unarmed; endopod represented by distally unipinnate claw accompanied by short seta basally.
P1–P2 and P4 with 3-segmented exopods. P1 with 2-segmented endopod; P2 and P4 with 1-segmented endopods. P3 transformed into a pincer-like structure. Intercoxal sclerites P1–P4 without ornamentation.
P1 (Fig. 2E): coxa without ornamentation. Basis with one outer seta, with spinule row along outer margin and row of fine spinules between exopod and endopod. Exopod about as long as endopod: exp-1 with one long and slender unipinnate outer spine and three transverse spinule rows on outer margin; exp-2 about half as long as exp-1, unarmed, ornamentation represented by distal spinule row on outer margin; exp-3 only slightly longer than exp-2, with two unipinnate outer spines, and two geniculate setae apically, with two outer spinule rows. Endopod: enp-1 only slightly shorter than exp-1 and exp-2 combined; with two transverse spinule rows along outer margin, one spinule row near about middle of inner margin, and a terminal row of fine spinules; enp-2 about half as long as enp-1, with one apical unipinnate spine and one geniculate seta, one outer and one inner spinule row.
P2 (Fig. 2F): coxa without ornamentation. Basis without outer seta, with spinule row along outer margin. Exopod elongate, exp-1 about as long as exp-2 and -3 combined; exp-1 with one bipinnate outer spine (densely spinulose along outer margin, and sparsely spinulose along inner margin), with two transverse spinule rows along outer margin, one spinule row distally and fine spinules around insertion of spine. Exp-2 unarmed; ornamentation consisting of one spinule row in distal third of outer margin and a terminal spinule row. Exp-3 about as long as exp-2, with one bipinnate outer spine and two subequal apical setae; all elements more densely spinulose along outer margin; one spinule row in distal third of outer margin and fine spinules around insertion of outer spine. Endopod 1-segmented, with one minute spinule in distal third of outer margin and three apical spinules, the medial one longer than the adjacent two.
P3 (Fig. 2G): coxa with one row of spinules distally. Basis with long outer seta and one row of spinules along outer margin; one anterior surface-pore. Exopod 1-segmented; former exp-1 elongate and slender, inwardly curved, with two spinule rows on outer margin; inner margin with lobate expansion proximally; outer spine inserted close to the beginning of former exp-2; former exp-2 very short, ending with spinous apophysis with rounded tip. Endopod absent.
P4 (Fig. 2H): coxa without ornamentation. Basis without outer seta, with spinule row along outer margin, with two curved outward articulated spinules, located near insertion of endopod. Exopod elongate, exp-1 about as long as exp-2 and -3 combined. Exp-1 with one bipinnate outer spine (densely spinulose along outer margin, and sparsely spinulose along inner margin), with two transverse spinule rows, one spinule row distally and fine spinules around insertion of outer spine. Exp-2 unarmed; ornamentation consisting of one spinule row in distal third of outer margin and a terminal spinule row. Exp-3 about as long as exp-2, with one bipinnate outer spine and one apical seta, both being more densely spinulose along outer margin; one spinule row in distal third of outer margin and fine spinules around insertion of outer spine. Endopod 1-segmented, terminal seta incorporated into segment.
P5 and P6 absent.
Female. Total body length from 302 to 365 mm, with mean of 324 mm based on five individuals. Habitus similar to male. No sexual dimorphism in body shape, morphology and ornamentation of cephalothorax, and caudal rami. Integumental windows located dorsally on the cephalic shield, on the anterior surface of the genital double-somite, and the second and third abdominal somites. Cephalic appendages identical in both sexes, excluding antennules. Urosome 5- segmented. Female genital and first abdominal somites completely fused forming genital doublesomite. Genital field located in anterior half of genital double-somite (Fig. 3A). Opercula well sclerotized, symmetrical, linear in shape and covering the copulatory pore (Fig. 3B).
Antennule (Fig. 3C) elongate, 7-segmented. Segment 1 with one ventral spinule row. Segment 2 longest. Armature formula: 1-[0], 2-[3 bare + 1 unipinnate], 3-[4], 4-[1 + (1 + ae)], 5-[1], 6-[1], 7-[7 + acrothek]. Apical acrothek consisting of two setae of different length and a slender, short aesthetasc. Aesthetasc on segment 4 reaching midlength of distal segment of antennule.
P2 (Fig. 3D): coxa without ornamentation. Basis without outer seta, with spinule row along outer margin. Exopod elongate, exp-1 about as long as exp-2 and -3 combined. Exp-1 with one bipinnate outer spine (densely spinulose along outer margin, and sparsely spinulose along inner margin), with two transverse spinule rows, one spinule row distally and fine spinules around insertion of outer spine. Exp-2 unarmed; ornamentation consisting of one spinule row in distal third of outer margin and a terminal spinule row. Exp-3 about as long as exp-2, with one bipinnate outer spine and two subequal apical setae; one spinule row along distal third of outer margin. Endopod 1-segmented, with two minute spinules in distal third of outer margin and four apical spinules.
P3 (Fig. 3E): coxa without ornamentation. Basis with long outer seta, with spinule row along outer margin. Anterior surface-pore present. Exopod elongate, exp-1 about 1.5 times longer than exp-2. Exp-1 with one bipinnate outer spine (densely spinulose along outer margin, and sparsely spinulose along inner margin) with two transverse spinule rows, one spinule row distally and fine spinules around insertion of outer spine. Exp-2 with one bipinnate outer spine and one apical seta; one spinule row along distal third of outer margin and fine spinules around insertion of outer spine. Endopod 1-segmented, pointed at distal tip, with minute spinules in distal third.
P4 (Fig. 3F): coxa without ornamentation. Basis without outer seta, with spinule row along outer margin. Exopod elongate. Exp-1 long, but shorter than exp-2 and -3 combined; one bipinnate outer spine (densely spinulose along outer margin, and sparsely spinulose along inner margin); two transverse spinule rows, one spinule row distally and fine spinules around insertion of outer spine. Exp-2 unarmed, with one spinule row in distal third of outer margin and a terminal spinule row. Exp-3 about as long as exp-2, with one bipinnate outer spine and one apical seta, one spinule row along distal third of outer margin and fine spinules around insertion of outer spine. Endopod 1-segmented, with three distal subequal setules.
P5 absent. No trace of P6 armature.
Etymology. The species name refers to the Latin adjective lethaea, derived from Lethe, a mythical spring in Hell.
description: Published as part of Galassi, Diana M. P. & Laurentiis, Paola De, 2004, Towards a revision of the genus Parastenocaris Kessler, 1913: establishment of Simplicaris gen. nov. from groundwaters in central Italy and review of the P. brevipes-group (Copepoda, Harpacticoida, Parastenocarididae), pp. 417-436 in Zoological Journal of the Linnean Society 140 (3) on pages 419-423, DOI: 10.1111/j.1096-3642.2003.00107.x, http://zenodo.org/record/4687271