Haploniscus cassilatus, Brökeland & Raupach, 2008

Brökeland, Wiebke & Raupach, Michael J., 2008, A species complex within the isopod genus Haploniscus (Crustacea: Malacostraca: Peracarida) from the Southern Ocean deep sea: a morphological and molecular approach, Zoological Journal of the Linnean Society 152 (4), pp. 655-706 : 660-692

publication ID	https://doi.org/ 10.1111/j.1096-3642.2008.00362.x
persistent identifier	https://treatment.plazi.org/id/03DC6362-F46C-FFDB-EF4A-C84DF335D01A
treatment provided by	Felipe
scientific name	Haploniscus cassilatus
status	sp. nov.

Treatment

HAPLONISCUS CASSILATUS View in CoL SP. NOV. ( Figs 2–7 View Figure 2 View Figure 3 View Figure 4 View Figure 5 View Figure 6 View Figure 7 , 40A View Figure 40 )

Holotype: Male, 3.9 mm; station 46-7, 60°38.33– 38.06′S 53°57.38–57.51′W, 5639 m depth; ZMH K40756 View Materials .

Paratypes: Same locality as holotype: four males, 3.5– 3.9 mm; three ovigerous females, 3.5–3.6; 21 females, 2.4–3.6 mm, 36 juveniles, 1.4–2.5 mm; ZMH K40757 View Materials .

Etymology: The species is named after the prominent rostrum; from Latin cassis, which means ‘helmet’, and latus, which means ‘carrying’.

Diagnosis: Body oval, length 3.0¥ width. Head width 2.5¥ length, frontal margin concave, with prominent rostrum; rostrum covered with small tubercles, with dorsal depression and acute upturned frontal tooth, a deep ventral indentation between rostrum and frontal margin of head. Pereonites 3–5 broadest. Lateral margins of pleotelson convex, posterolateral processes short, not reaching terminal margin; dorsal surface of pleotelson with two sharp longitudinal keels, ventral surface with cuticular bulge surrounding the branchial chamber and tapering towards anus. Antenna 1 with four flagellar articles. Carpus with 1–3 flagellate spine-like setae, apical and ventral combs of carpus spinose, carpus of pereopods 5 and 6 with dorsal flagellate seta. Pleopod 1 with nearly continuous distal margin. Endopod of pleopod 2 as long as basipod. Uropods not reaching terminal margin.

Description of female paratype: Body oval. Margins of pereonites straight, smooth. Pereonites 3–5 broadest. Pleotelson length 0.2¥ body length, tapering distally, distance between pleotelson processes 2.1¥ anterior margin width; terminal margin convex. Cuticle of body smooth.

Antenna 1 ( Fig. 3 View Figure 3 ) length 0.3¥ body length, article 1 broadest, length 1.5¥ width, article 2 length 1.3¥ article 1 length, width 0.5¥ article 1 width, both articles with several broom and simple setae; article 3 length 0.4¥ article 2 length, with simple seta; flagellum article 1 shortest, with broom seta; articles 2–4 of subequal length, article 2 with simple seta, article 3 with one aesthetasc and one simple seta, article 4 with two aesthetascs and two simple setae.

Antenna 2 ( Fig. 3 View Figure 3 ) length 0.7¥ body length, articles 1 and 2 slightly wider than long, with simple seta, article 3 about as long as wide, length 2.0¥ article 2 length, with short dorsal tooth and several simple setae, article 4 length 0.8¥ article 3 length, 1.1¥ width, article 5 length 1.5¥ article 3 length, 0.9¥ article 6 length, 2.4¥ width, article 6 length 1.6¥ article 3 length, 4.0¥ width, both articles with several simple and some broom setae, articles 4–6 covered with numerous triangular scales; flagellum length 0.7¥ peduncle length, 14-articulated, each article with several simple setae.

Mandible ( Fig. 4 View Figure 4 ) incisor with five blunt teeth, lacinia mobilis of left mandible with five teeth, right mandible with stout serrated spine-like seta instead, spine row comprising two serrated and four simple spine-like setae; molar tooth row with about seven teeth and eight setulated setae proximally, cuticular ledge tapering off forming a tooth on both sides, right mandible with row of six accessory teeth proximally of cuticular ledge; palp article 2 with three serrated spine-like setae proximally of insertion of article 3, article 3 with ten serrated spine-like setae of increasing length.

Maxilla 1 ( Fig. 3 View Figure 3 ) outer lobe with seven simple and five serrated spine-like setae and several simple setae on lateral and medial margin and surface; inner lobe apically with several stout simple setae.

Maxilla 2 ( Fig. 3 View Figure 3 ) outer lobe with two long and two short simple spine-like setae apically, several simple setae on lateral margin; medial lobe with two long and one shorter simple spine-like setae and one serrated seta apically, medial margin with six spine-like setae; inner lobe with two apical serrated spine-like setae, three stout apical simple setae and numerous simple setae on surface and medial margin.

Maxilliped ( Fig. 3 View Figure 3 ) endite apical margin with three small fan setae and two short spine-like setae, ventral surface with numerous simple setae, separated apical medial margin dorsally with one simple spine-like seta, one serrated spine-like seta and row of simple setae, medial margin with four retinacula; epipod slightly longer than endite.

Pereopods ( Figs 4–6 View Figure 4 View Figure 5 View Figure 6 ): Basis with 3–4 long simple setae ventrally, basis of pereopods 2–6 with 1–2 broom setae dorsally. Ischium with three simple setae ventrally and dorsally (some broken off in type specimen). Merus with 3–4 setae apically and one simple seta ventrally, pereopods 5–7 with apical ventral flagellate seta, ventral seta on pereopods 5–7 spinelike. Ventral comb-like scale rows of carpus and propodus spinose; carpus with 1–3 flagellate setae and several simple setae, dorsal flagellate seta on pereopods 5 and 6; apical comb on carpus of pereopod 1 small and setose, apical combs on pereopods 2–7 comprising one small and one larger spinose comb. Propodus with 2–6 simple setae ventrally, pereopods 5–7 with 2–3 flagellate spine-like setae ventrally, pereopods 1–4 with mediodorsal simple seta. Dactylus with three lateral setae; accessory tooth acute.

Pleopods ( Fig. 6 View Figure 6 ): Pleopod 2 subcircular, with more than 40 setae on distal and lateral margins, longest setae on distal margin. Pleopod 3 endopod length 1.6¥ width, with rounded distal margin; exopod small, length 1.8¥ width, 0.5¥ endopod length, width 0.4¥ endopod width, lateral margin rounded, with six simple setae and fringe of fine bristles. Pleopod 4 endopod length 1.6¥ width; exopod length 4.4¥ width, 0.6¥ endopod length, width 0.2¥ endopod width, lateral margin rounded with fringe of long bristles, plumose seta slightly longer than exopod. Pleopod 5 length 1.6¥ width.

Uropods ( Fig. 2 View Figure 2 ) not reaching terminal margin.

Description of male: The male ( Figs 2 View Figure 2 , 7 View Figure 7 , 40A View Figure 40 ) differs from the female in the following characters.

Antenna 2 ( Fig. 7 View Figure 7 ) more stout, with more than 14 flagellar articles, flagellar articles with more setae.

Pleopod 1 ( Fig. 7 View Figure 7 ) length 1.9¥ width, broadest part in the proximal quarter, 1.9¥ broader than narrowest part, lateral margins with two simple setae, distal margins with about nine setae each, sympods distal margin continuous, ventral surface with mediolateral bulges covered with numerous bristles, transverse grooves in the distal third with several bristles. Pleopod 2 ( Fig. 7 View Figure 7 ) basipod length 2.1¥ width, with several simple setae on lateral and distal margin; endopod inserting in distal half of basipod, short, stout, as long as basipod, article 2 length about 3.0¥ article 1 length, expanding in the medial part, sperm duct reaching from endopod tip almost to proximal third of article 2, exopod small, inserting in the distal third of basipod.

HAPLONISCUS CUCULLUS SP. NOV.

( FIGS 8–14 View Figure 8 View Figure 9 View Figure 10 View Figure 11 View Figure 12 View Figure 13 View Figure 14 , 40B View Figure 40 , 41 View Figure 41 )

Holotype: Subadult male, 5.3 mm; station 43-8, 60°27.13–27.19′S, 56°05.12–04.81′W, 4782 m depth, ZMH K40758 View Materials .

Paratypes: Same locality as holotype: one ovigerous female, 5.4 mm; one female, 2.8 mm; one juvenile, 2.2 mm; ZMH K40759 View Materials . Station 42-2, 59°40.30– 40.32′S, 57°35.42–42.64′W, 3689 m depth: one ovigerous female, 5.9 mm; three females, 3.4–3.6 mm; eight juveniles, 3.3–3.6 mm; ZMH K40760 View Materials .

Etymology: The name refers to the cap-like rostrum that is extraordinarily large in this species; the Latin cucullus means ‘cap’ or ‘hood’.

Diagnosis: Body oval, length 3.0¥ width. Head width 2.5¥ length, frontal margin concave, with prominent rostrum; rostrum covered with small tubercles, with dorsal depression and acute upturned frontal tooth, a deep ventral indentation between rostrum and frontal margin of head. Pereonites 3–5 broadest. Lateral margins of pleotelson convex basally, concave distally, posterolateral processes short, not reaching terminal margin; dorsal surface of pleotelson with two sharp longitudinal keels, ventral surface with cuticular bulge surrounding the branchial chamber and tapering towards anus. Antenna 1 with four flagellar articles. Maxilliped with three retinacula. Carpus of pereopods 1–4 with 3–4 ventral flagellate setae, of pereopods 5–7 with 4–6 ventral flagellate setae, apical and ventral combs of carpus spinose, carpus of pereopods 5 and 6 with dorsal flagellate seta.

Description of female: H. cucullus differs from H. cassilatus in the following characters.

Rostrum ( Fig. 13 View Figure 13 ) slightly larger, less tapering distally, curved slightly stronger dorsally in lateral view.

Pleotelson ( Fig. 8 View Figure 8 ) lateral margin convex in basal half, concave in distal half, posterolateral processes slightly longer, distance between processes 1.6¥ anterior margin width.

Antenna 2 ( Fig. 9 View Figure 9 ) article 4 length 1.3¥ width, article 5 length 2.7¥ width, 0.8¥ article 6 length, article 6 length 1.8¥ article 3 length, 5.5¥ width.

Mandibular ( Fig. 9 View Figure 9 ) palp article 3 with about ten serrated spines.

Maxilliped ( Fig. 10 View Figure 10 ) with three retinacula.

Pereopods ( Fig. 10 View Figure 10 , 11 View Figure 11 ): Basis with 3–5 ventral setae. Merus with 1–2 medioventral simple setae on pereopods 5–7. Carpus of pereopods 1–4 with 3–4 ventral flagellate setae, pereopods 5–7 with 4–6 ventral flagellate setae.

Description of male: No adult males were found; the subadult male differs from the female in the following characters.

Pleopod 1 ( Fig. 13 View Figure 13 ) similar to that of H. cassilatus , but lacking the transversal grooves on the dorsal surface, due to immaturity. Penes present. Pleopod 2 sperm duct not developed.

HAPLONISCUS WEDDELLENSIS SP. NOV.

( FIGS 15–19 View Figure 15 View Figure 16 View Figure 17 View Figure 18 View Figure 19 , 40C View Figure 40 )

Holotype: Male, 3.0 mm; station 133-3, 65°20.17– 20.08′S, 54°14.30–14.34′W, 1314 m depth, ZMH K40761 View Materials .

Paratypes: Same locality as holotype : 16 males, 2.6– 3.0 mm; three ovigerous females 3.5–4.2 mm; nine females, 2.3–2.9 mm; 11 juveniles, 1.2–2.3 mm; ZMH K40762 View Materials .

Etymology: Named after the type locality in the Weddell Sea.

Diagnosis: Body oval, length 3.0¥ width. Head width 2.5¥ length, frontal margin concave, with prominent rostrum; rostrum covered with small tubercles, with shallow dorsal depression and acute upturned frontal tooth, a deep ventral indentation between rostrum and frontal margin of head. Pereonites 3–6 broadest. Lateral margins of pleotelson convex basally, concave distally, posterolateral processes slightly exceeding terminal margin; dorsal surface of pleotelson with two sharp longitudinal keels, ventral surface with cuticular bulge surrounding the branchial chamber and tapering towards anus. Antenna 1 with four flagellar articles. Carpus of pereopods 1–4 with 2–4 ventral flagellate setae, of pereopods 5–7 with 2–3 ventral flagellate setae, apical and ventral combs of carpus spinose, carpus of pereopod 6 with dorsal flagellate seta.

Description of female: H. weddellensis differs from H. cassilatus in the following characters.

Rostrum ( Fig. 16 View Figure 16 ) shorter and broader, dorsal depression shallow. Pereonites 3–6 broadest. Pleotelson ( Fig. 16 View Figure 16 ) lateral margins convex basally, concave distally, posterolateral processes longer, exceeding terminal margin slightly, distance between processes 1.8¥ anterior margin width.

Antenna 2 article 5 length 1.6¥ article 3 length, 1.1¥ article 6 length, 2.1¥ width, article 6 length 1.4¥ article 3 length, 3¥ width.

Mandibular palp with about eight serrated setae.

Carpus with 2–4 ventral flagellate setae, only carpus of pereopod 6 with dorsal flagellate seta.

Description of male: Pleopods 1 and 2 ( Fig. 19 View Figure 19 ) are more or less identical with the pleopods of H. cassilatus .

HAPLONISCUS PROCERUS SP. NOV.

( FIGS 20–25 View Figure 20 View Figure 21 View Figure 22 View Figure 23 View Figure 24 View Figure 25 , 40D View Figure 40 )

Holotype: Female, 7.4 mm; station 131-3, 65°19.83– 19.99′S, 51°31.61–31.23′W, 3553 m depth; ZMH K40763 View Materials .

Paratype: Same locality as holotype: one female, 7.6 mm ; ZMH K40764 View Materials .

Etymology: The name refers to the rostrum, which is elongated in this species; the Latin term procerus means ‘large’, ‘slender’, ‘long’.

Diagnosis: Body oval, length 3.0¥ width. Head width 2.5¥ length, frontal margin concave, with prominent rostrum; rostrum covered with small tubercles, with dorsal depression and acute upturned frontal tooth, a deep ventral indentation between rostrum and frontal margin of head. Pereonites 3–6 broadest. Lateral margins of pleotelson convex basally, concave distally, posterolateral processes slightly exceeding terminal margin; dorsal surface of pleotelson with two sharp, pronounced longitudinal keels, ventral surface with cuticular bulge surrounding the branchial chamber and tapering towards anus. Antenna 1 with four flagellar articles. Maxilliped with three retinacula. Carpus of pereopods 1–4 with 4–5 ventral flagellate setae, of pereopods 5–7 with 7–8 ventral flagellate setae, apical and ventral combs of carpus spinose, carpus of pereopods 5–7 with dorsal flagellate seta.

Description of female paratype: H. procerus differs from H. cassilatus in the following characters.

Rostrum larger, less tapering, less vaulted, distal part elongated. Pereonites 3–6 broadest. Lateral margins of pleotelson convex basally, slightly concave distally, dorsal keels more pronounced, pleotelson processes slightly exceeding terminal margin, distance between processes 1.3¥ anterior margin width.

Antenna 2 ( Fig. 21 View Figure 21 ) article 4 length 0.7¥ article 3 length, 0.9¥ width, article 5 about as long as article 6, length 2¥ width, article 6 length 4.8¥ width. Scales small, more numerous.

Mandibular ( Fig. 21 View Figure 21 ) palp with 12 serrated setae.

Maxilliped ( Fig. 22 View Figure 22 ) with three retinacula.

Pereopods ( Figs 23 View Figure 23 , 24 View Figure 24 ): Basis with 4–6 setae ventrally. Merus of pereopods 1–4 with 2–3 simple medioventral setae, of pereopods 5–7 with 1–2 medioventral flagellate setae. Carpus of pereopods 1–4 with 4–5 ventral flagellate setae, of pereopods 5–7 with 7–8 ventral flagellate setae, dorsal apical flagellate seta on carpus of pereopods 5–7 (broken off on pereopod 7).

Description of male: No males of this species are known.

Remarks: Besides the above described species three juvenile specimens of a Haploniscus species possessing the characteristic rostrum were found at station 131 together with the two adults of H. procerus . These possess a much shorter rostrum than H. procerus and could not be allocated clearly to one of the newly described species.

HAPLONISCUS KYRBASIA SP. NOV.

( FIGS 26– 31 View Figure 26 View Figure 27 View Figure 28 View Figure 29 View Figure 30 View Figure 31 , 40E View Figure 40 )

Holotype: Male, 5.7 mm; station 141-10, 58°15.98– 16.28′S, 24°53.73–54.09′W, 4183 m depth; ZMH K40765 View Materials .

Etymology: Kyrbasia is the name of a Persian hat with peaked crown; the name refers to the rostrum.

Diagnosis: Body oval, length 3.0¥ width. Head width 3.0¥ length, frontal margin concave, with prominent rostrum; rostrum covered with small tubercles, with dorsal depression and acute upturned frontal tooth, a deep ventral indentation between rostrum and frontal margin of head. Pereonites 3–5 broadest. Lateral margins of pleotelson convex basally, concave distally, posterolateral processes short, not reaching terminal margin; dorsal surface of pleotelson with two sharp longitudinal keels, ventral surface with cuticular bulge surrounding the branchial chamber and tapering towards anus. Antenna 1 with four flagellar articles. Maxilliped with three retinacula. Carpus of pereopods 1–4 with four flagellate setae, of pereopods 5–7 with 5–6 flagellate setae, apical and ventral combs of carpus spinose, carpus of pereopods 5 and 6 with dorsal flagellate seta. Pleopod 1 with nearly continuous distal margin. Endopod of pleopod 2 as long as basipod.

Description of male holotype: H. kyrbasia differs from H. cassilatus in the following characters.

Head ( Figs 26 View Figure 26 , 40E View Figure 40 ) width 3.0¥ length. Rostrum slightly larger, less tapering, curved slightly stronger dorsally in lateral view. Pleotelson ( Fig. 25 View Figure 25 ) lateral margins convex basally, concave distally, distance between pleotelson processes 1.5¥ anterior margin width.

Antenna 1 ( Fig. 27 View Figure 27 ) flagellar articles 3 and 4 with one aesthetasc each.

Antenna 2 ( Fig. 27 View Figure 27 ) article 4 length 0.9¥ article 3 length, 1.4¥ width, article 5 length 1.8¥ article 3 length, about as long as article 6, length 2.6¥ width, article 6 length 1.8¥ article 3 length.

Mandibular ( Fig. 27 View Figure 27 ) palp article 3 with ten serrated setae.

Maxilliped ( Fig. 28 View Figure 28 ) with three retinacula.

Pereopods ( Figs 29 View Figure 29 , 30 View Figure 30 ): Basis with four ventral setae. Merus with two medioventral setae. Carpus of pereopods 1–4 with four flagellate setae, of pereopods 5–7 with 5–6 flagellate setae. Propodus of pereopods 5–7 with one ventral flagellate seta.

Description of female: Only the male holotype of this species is known.

HAPLONISCUS NUDIFRONS SP. NOV.

( FIGS 32–35 View Figure 32 View Figure 33 View Figure 34 View Figure 35 )

Holotype: Female, 11.3 mm; station 129-2, 59°52.21– 52.20′S, 59°58.75–58.63′W, 4076 m depth; ZMH K40766 View Materials .

Etymology: The name refers to the absence of the rostrum that is characteristic for the other species of the Haploniscus cucullus complex; the Latin nudus meaning ‘naked’.

Diagnosis: Body oval, length 3.0¥ width. Head width 2.5¥ length, frontal margin concave, without rostrum. Pereonites 3–5 broadest. Lateral margins of pleotelson convex, posterolateral processes short, not reaching terminal margin; dorsal surface of pleotelson with two sharp longitudinal keels, ventral surface with cuticular bulge surrounding the branchial chamber and tapering towards anus. Carpus with 3–4 flagellate spine-like setae, apical and ventral combs of carpus spinose, carpus of pereopods 5 and 6 with dorsal flagellate seta. Pleopod 2 of female without setae on lateral margins. Uropods reaching terminal margin of pleotelson.

Description of female holotype: H. nudifrons differs from H. cassilatus in the following characters.

Head ( Fig. 32 View Figure 32 ) without rostrum.

Distance between pleotelson processes 1.7¥ pleotelson anterior margin width.

Distal articles of antennae ( Fig. 35 View Figure 35 ) lost.

Maxilliped with three retinacula.

Pereopods ( Figs 33 View Figure 33 , 34 View Figure 34 ): Merus with 1–2 medioventral setae. Carpus with 3–4 ventral flagellate setae.

Pleopod 2 ( Fig. 35 View Figure 35 ) lateral margins, without setae, distal margin with about 20 setae.

Uropods ( Fig. 32 View Figure 32 ) reaching terminal margin of pleotelson.

Description of male: Only the female holotype of this species is known.

HAPLONISCUS MICROKORYS SP. NOV.

( FIGS 36–39 View Figure 36 View Figure 37 View Figure 38 View Figure 39 , 40F View Figure 40 )

Holotype: Male, 4.3 mm; station 134-3, 65°19.20– 19.05′S, 48°03.77–02.92′W, 4553 m depth; ZMH K40767 View Materials .

Etymology: From the Greek words micros meaning small and korys meaning helmet; the name refers to the rostrum, which is smaller than in most species of the Haploniscus cucullus complex.

Diagnosis: Body oval, length 3.0¥ width. Head width 2.5¥ length, frontal margin concave, with triangular rostrum; rostrum pointing ventrally with acute frontal tooth, a deep ventral indentation between rostrum and frontal margin of head. Pereonites 3–5 broadest. Lateral margins of pleotelson convex basally, concave distally, posterolateral processes short, not reaching terminal margin; dorsal surface of pleotelson with two sharp longitudinal keels, ventral surface with cuticular bulge surrounding the branchial chamber and tapering towards anus. Antenna 1 with five flagellar articles. Maxilliped with three retinacula. Carpus of pereopod 1 with six ventral flagellate setae, of pereopods 2–7 with 7–11 ventral flagellate setae, apical and ventral combs of carpus spinose, carpus of pereopods 5 and 6 with dorsal flagellate seta. Pleopod 1 with nearly continuous distal margin. Endopod of pleopod 2 as long as basipod.

Description of male holotype: H. microkorys differs from H. cassilatus in the following characters.

Rostrum ( Figs 36 View Figure 36 , 40F View Figure 40 ) smaller, pointing ventrally, triangular in dorsal view, without dorsal depression.

Lateral margins of pleotelson ( Fig. 36 View Figure 36 ) convex basally, concave distally, distance between processes 2.0¥ anterior margin width.

Antenna 1 ( Fig. 37 View Figure 37 ) with five flagellar articles, articles 3 and 4 with one aesthetasc, article 5 with two aesthetascs.

Antenna 2 ( Fig. 37 View Figure 37 ) article 4 length 0.5¥ article 3 length, 0.9¥ width, article 5 length 0.8¥ article 6 length, 3.3¥ width, article 6 length 1.9¥ article 3 length, 5.6¥ width.

Mandibular ( Fig. 37 View Figure 37 ) palp article 3 with 11 serrated setae.

Maxilliped with three retinacula.

Pereopods ( Figs 38 View Figure 38 , 39 View Figure 39 ): Basis with 4–7 ventral setae. Ischium with 3–6 ventral setae. Merus of pereopods 1–4 with 3–4 medioventral simple setae, of pereopods 5–7 with three medioventral flagellate setae. Carpus of pereopod 1 with six ventral flagellate setae, of pereopods 2–7 with 7–11 ventral flagellate setae. Propodus of pereopods 2–4 with almost 20 simple setae ventrally, propodus of pereopods 5–7 with 1–2 ventral flagellate setae and several simple setae.

Exopod of pleopod 3 ( Fig. 37 View Figure 37 ) with 12 setae.

Description of female: Only the male holotype of this species is known.