Anchistylis halei, Gerken, 2014

Gerken, Sarah, 2014, Eleven New Species and a New Genus of Diastylidae (Crustacea: Cumacea) from Australia and One New Species from Canada, Records of the Australian Museum 66 (1), pp. 1-62 : 3-8

publication ID	https://doi.org/ 10.3853/j.2201-4349.66.2014.1601
persistent identifier	https://treatment.plazi.org/id/03FB87F1-2466-2503-FEB8-FC02FC5DF82A
treatment provided by	Carolina
scientific name	Anchistylis halei
status	sp. nov.

Treatment

Anchistylis halei View in CoL n. sp.

Figs 1–4 View Figure 1 View Figure 2 View Figure 3 View Figure 4

Type material. Holotype ovigerous female, AM P85793; paratype ovigerous female, dissected, AM P85794; paratype adult male, dissected, AM P85795; 35°04'S 150°41'12"E, 12 m, P. A. Hutchings, 1989–1990. GoogleMaps

Other material examined. 1 male, AM P85796 ; AM P85797 , 4 females, 6 males, 2 juveniles; 1 female, AM P85798 ; 1 male, AM P85799 ; 1 male, AM P85800 ; 4 males, AM P85801; 35°04'S 150°41'12"E, 12 m GoogleMaps , P. A. Hutchings, 1989–1990. 1 individual, AM P53667, 33°58'16"S 151°09'55"E, 3 m GoogleMaps , State Pollution Control Commission, 1976.

Diagnosis. Female and subadult male. Carapace with two lateral ridges curving towards antennal notch, ending on anterior margin of carapace. Uropod endopod article 1 longer than articles 2 and 3 together. Adult male. Carapace as in female. Pleopods aramous.

Description

Ovigerous female. Holotype ovigerous female, AM P85793, 2.0 mm; paratype ovigerous female, AM P85794, 2.7 mm. —Carapace lateral ridge curving from ventral part of antennal notch dorsally and turning anteriorly on dorsal part of carapace, with second shorter ridge anterior of longer ridge, starting above antennal notch; pseudorostral lobes 0.4 × carapace length; eye lobe broad, 0.07 carapace length, with lenses; carapace subequal to length of pereonites ( Fig. 1A–C View Figure 1 ). — Paratype ovigerous female, AM P85794, 2.7 mm. —Antennule peduncle article 1 longest, unarmed; article 2 with 2 setae; article 3 with 2 setae; main flagellum of 3 articles, with several simple setae and 2 aesthetascs; accessory flagellum of 1 article, less than 0.5 length of main flagellum article 1, with 3 simple setae ( Fig. 1D View Figure 1 ). —Antenna of 4 articles, each article with single pappose seta ( Fig. 1D View Figure 1 ). —Mandible navicular, with 8–9 microserrate setae medially, lacinia mobilis with 2 cusps ( Fig. 1E View Figure 1 ). —Maxillule with 2 endites; outer endite with 3 rows of stout simple setae; inner endite with 2 simple, 1 tricuspid and 1 microserrate setae; palp broken ( Fig. 1F View Figure 1 ). —Maxilla with 3 endites; broad endite distal margin lined with slender setae, medial margin with row of simple setae and 2 pappose setae; medial narrow endite with 4 microserrate setae terminally; distal narrow endite with 4 microserrate setae terminally; both narrow endites extending past margin of broad endite ( Fig. 1G View Figure 1 ). —Maxilliped 1 basis produced as medial lobe with row of pappose setae and 2 hook setae; ischium absent; merus with 2 pappose setae; carpus 1.5 × merus length, with 2 pappose setae, 7 beak-like, and field of simple setae medially; propodus 0.8 × carpus length, with 4 pappose setae medially and plumose seta laterally; dactylus 0.9 × propodus length, with 3 simple and 1 pappose setae terminally ( Fig. 1H View Figure 1 ). —Maxilliped 2 basis longer than all other articles together, with 4 simple and 4 pappose setae; ischium absent; merus 0.2 × basis length, with pappose seta; carpus 2.1 × merus length, with 6 simple setae; propodus 0.7 × carpus length, with 8 simple and 1 plumose setae; dactylus 0.6 × propodus length, with 3 simple setae terminally ( Fig. 1I View Figure 1 ). —Maxilliped 3 basis 1.8 × all other articles together, with 11 pappose setae medially, distal margin produced to midpoint of merus, with 6 plumose setae; ischium 0.09 × basis length, unarmed; merus 1.6 × ischium length, with 2 pappose setae medially, plumose seta laterally; carpus 1.0 × merus length, with 2 sparsely plumose setae medially, plumose seta laterally; propodus 0.8 × carpus length, with 2 sparsely plumose setae medially, 2 plumose setae laterally; dactylus 1.0 × propodus length, with 5 simple setae terminally; exopod 0.6 × basis length, basal article unarmed, flagellum with plumo-annulate setae ( Fig. 2A View Figure 2 ). —Left (normal) pereopod 1 basis 0.8 × length of all other articles together, with 9 pappose, 1 plumose and 1 stout simple setae; ischium 0.1 × basis length, with plumose seta; merus 1.1 ischium length, with 1 pappose and 1 simple setae; carpus 2.8 × merus length, with 2 simple setae; propodus 1.0 × carpus length, with simple seta; dactylus 0.7 × propodus length, with 8 simple setae distally; exopod 0.8 × basis length, basal article with 3 pappose setae, flagellum with plumo-annulate setae ( Fig. 2B View Figure 2 ). —Right (aberrant) pereopod 1 basis 1.4 × length of all other articles together, with 9 pappose, 1 plumose and 1 stout simple setae; ischium 0.07 × basis length, with plumose seta; merus 1.5 × ischium length, unarmed; carpus 2.5 × merus length, unarmed; propodus 0.7 × carpus length, unarmed; dactylus 0.9 × propodus length, with 4 simple setae distally; exopod 0.8 × basis length, basal article with 2 pappose setae, flagellum with plumo-annulate setae ( Fig. 2C View Figure 2 ). —Pereopod 2 basis 0.7 × length of all other articles together, with 2 simple and 13 pappose setae; ischium 0.08 × basis length, unarmed; merus 4.3 × ischium length, with 2 simple and 2 pappose setae; carpus 1.1 × merus length, unarmed; propodus 0.6 × carpus length, with simple seta; dactylus 1.6 × propodus length, with 4 simple setae and 3 simple setae terminally; exopod 1.2 × basis length, basal article with pappose seta, flagellum with plumo-annulate setae ( Fig. 2D View Figure 2 ). —Pereopod 3 basis 0.8 × length of all other articles together, with 2 pappose and 7 plumose setae; ischium 0.1 × basis length, unarmed; merus 5.0 × ischium length, with simple seta; carpus 0.3 × merus length, with 3 simple and 6 annulate setae; propodus 0.9 × carpus length, with annulate seta; dactylus 0.6 × propodus length, with 1 simple seta and serrate seta terminally; exopod rudimentary, 0.4 × basis length, of 2 articles with 2 simple, 1 pappose and 1 plumose setae ( Fig. 2E View Figure 2 ). —Pereopod 4 basis 0.7 × length of all other articles together, with 5 plumose and 1 pappose setae; ischium 0.06 × basis length, unarmed; merus 12.5 × ischium length, with 2 annulate setae; carpus 0.4 × merus length, with 7 annulate setae; propodus 0.6 × carpus length, with annulate seta; dactylus 0.8 × propodus length, with 2 simple setae and serrate seta terminally; exopod rudimentary, 0.4 × basis length, of 2 articles with 2 pappose and 1 plumose setae ( Fig. 2F View Figure 2 ). —Pereopod 5 basis 0.7 × length of all other articles together, with 1 simple and 7 pappose setae; ischium 0.08 × basis length, with 1 simple and 1 annulate setae; merus 7 × ischium length, with 2 annulate setae; carpus 0.6 × merus length, with 11 annulate setae; propodus 0.6 × carpus length, with annulate seta; dactylus 1.0 × propodus length, with 1 simple seta and serrate seta terminally ( Fig. 2G View Figure 2 ). —Telson 0.8 × length of pleonite 6, with 1 pair of tiny hair-like setae laterally, no terminal setae ( Fig. 2H View Figure 2 ). —Uropod peduncles 1.0 × pleonite 6 length, 1.2 × telson length, with 2 setae with single subterminal setule medially. Uropod endopod of 3 articles, 1.4–1.5 × peduncle length, margins lined with fine hair-like setae; article 1 longer than articles 2 and 3 together, with 8–9 setae with single subterminal setule medially; article 2 shortest, with 2 setae with single subterminal setule medially; article 3 with 2 setae with single subterminal setule medially, 1 laterally, terminal seta longer than article 3, with single subterminal setule. Uropod exopod of 2 articles, subequal to length of endopod, margins lined with fine hair-like setae; article 1 0.2 × length of article 2, with simple seta; article 2 with 6–10 setae with single subterminal setule marginally, terminal seta longer than endopod terminal seta, with single subterminal setule ( Fig. 2H View Figure 2 ).

Adult male. Paratype adult male, AM P85795, 3.5 mm. — Carapace lateral ridge curving from ventral part of antennal notch dorsally and turning anteriorly on dorsal part of carapace, with second shorter ridge anterior of longer ridge, starting above antennal notch; eye lobe with lenses; carapace 1.8 × length of pereonites together ( Fig. 3A View Figure 3 ). —Antennule peduncle article 1 longer than articles 2 and 3 together, with 2 simple setae; article 2 0.5 × length of article 1, unarmed; article 3 0.7 × length of article 2, with short simple setae distally; main flagellum of 6 articles, with many short simple setae, 2 aesthetascs terminally; accessory flagellum of 3 articles, 0.7 × length of main flagellum, with simple setae terminally ( Fig. 3B View Figure 3 ). —Antenna extending past telson; peduncle of 5 articles; article 3 with pappose seta, article 5 with ranks of setae on anterior face, ranks do not circle article; flagellum with long articles, each with several small simple setae ( Fig. 3C View Figure 3 ). —Maxilliped 3 basis 2.0 × length of all other articles together, with 3 simple and 10 plumose setae medially, distal corner produced to midpoint of merus, with 5 plumose setae; ischium 0.07 × basis length, unarmed; merus 1.7 × ischium length, with 3 pappose and 1 plumose setae; carpus 1.0 × merus length, with 6 pappose and 1 plumose setae; propodus 0.6 × carpus length, with 2 pappose setae; dactylus 1.7 × propodus length, with 4 simple setae terminally; exopod 0.8 × basis length, basal article unarmed, flagellum with plumo-annulate setae ( Fig. 3D View Figure 3 ). —Pereopod 1 basis 1.0 × length of all other articles together, with 9 pappose, 1 plumose and 1 stout simple setae; ischium 0.06 × basis length, unarmed; merus 2.2 × ischium length, with 1 plumose and 1 pappose setae; carpus 2.1 × merus length, with 2 simple setae; propodus 1.1 × carpus length, with 3 simple setae; dactylus 0.8 × propodus length, with 4 simple setae and 3 simple setae terminally; exopod 0.7 × basis length, basal article width 1.7 × width of basis, with 3 pappose setae, flagellum with plumo-annulate setae ( Fig. 4A View Figure 4 ). —Pereopod 2 basis 1.0 × length of all other articles together, with 10 pappose setae; ischium 0.04 × basis length, unarmed; merus 6.0 × ischium length, with 1 simple and 1 pappose setae; carpus 1.1 × merus length, with 4 simple setae; propodus 0.5 × carpus length, with 4 simple setae; dactylus 1.6 × propodus length, with 6 simple setae and 3 simple setae terminally; exopod 1.0 × basis length, basal article width 1.7 × width of basis, with 3 pappose setae, flagellum with plumo-annulate setae ( Fig. 3E View Figure 3 ). —Pereopod 3 basis 0.95 × length of all other articles together, with 7 pappose setae; ischium 0.07 × basis length, with 3 annulate setae; merus 9.0 × ischium length, with 3 annulate setae; carpus 0.3 × merus length, with 5 annulate setae; propodus 0.8 × carpus length, with annulate seta; dactylus 0.7 × propodus length, with 2 simple setae and serrate seta terminally; exopod 1.2 × basis length, basal article width 1.3 × width of basis, with 2 pappose setae, flagellum with plumo-annulate setae ( Fig. 4B View Figure 4 ). —Pereopod 4 basis 0.8 × length of all other articles together, with 3 pappose, 2 plumose and 1 annulate setae; ischium 0.08 × basis length, with 2 annulate setae; merus 7.3 × ischium length, with 3 annulate and 1 plumose setae; carpus 0.4 × merus length, with 8 annulate setae; propodus 0.6 × carpus length, with annulate seta; dactylus 1.2 × propodus length, with 2 simple setae and serrate seta terminally; exopod 1.4 × basis length, basal article width 1.3 × width of basis, with 4 plumose setae, flagellum with plumo-annulate setae ( Fig. 4C View Figure 4 ). —Pereopod 5 basis 0.6 × length of all other articles together, with 4 pappose setae; ischium 0.2 × basis length, with annulate seta; merus 2.8 × ischium length, with 3 annulate setae; carpus 0.8 × merus length, with 8 annulate and 1 pappose setae; propodus 0.7 × carpus length, with annulate seta; dactylus 0.7 × propodus length, with simple seta and serrate seta terminally ( Fig. 4D View Figure 4 ). —Pleopod 1 without rami, with 2 stout, curved hook setae ( Fig. 4E View Figure 4 ) —Pleopod 2 without rami, with excavation and small seta indicating division between peduncle and ramus, but without articulation, with 1 pappose, 1 curved hook, and 1 complex bicuspid seta terminally ( Fig. 4F View Figure 4 ). —Telson 1.1 × length of pleonite 6, without lateral setae, 2 long slender terminal setae ( Figs 4G–H View Figure 4 ). —Uropod peduncles 1.5 × pleonite 6 length, 1.5 × telson length, medial margin lined with fine hair-like setae, with 4 setae with single subterminal setule distally. Uropod endopod of 3 articles, 1.6 × peduncle length, medial margins lined with fine hair-like setae; article 1 longer than articles 2 and 3 together, with 8–10 setae with single subterminal setule medially; article 2 with 3 setae with single subterminal setule medially; article 3 1.0 × article 2 length, with 4–5 setae with single subterminal setule medially, 1 laterally, terminal seta shorter than article 3, simple with single subterminal setule. Uropod exopod 0.9 × length of endopod; article 1 0.3 × article 2 length, with 0–1 simple seta; article 2 with 4 setae on each margin, terminal seta long with single subterminal setule ( Fig. 4G View Figure 4 ).

Etymology. The species is named halei in honor of the extensive work by Herbert Hale on the Australian cumacean fauna.

Remarks. The new species has a unique carapace within the Australian Anchistylis . The other three Australian species of Anchistylis have a single lateral ridge curving towards the antennal notch and a depression at the antennal border bounded by a small ridge. In comparison, the new species has two parallel lateral ridges curving toward the antennal border and meeting the anterior margin of the carapace, and no small ridge or depression at the antennal border. The new species also agrees with the observation of Roccatagliata (1997) that Australian Anchistylis have two strong hook-like setae on pleopod 1, while the South American Anchistylis have one hook-like seta on pleopod 1.The new species is also unique within the genus in that the pleopods are reduced to being entirely without rami. There is an excavation on the side of pleopod 2 that indicates the site of the articulation between the peduncle and ramus, but there is no articulation present.

The paratype ovigerous female that was dissected had a variation in morphology between the right and left first pereopod. The left pereopod 1 is similar in proportions, length and setation to both the holotype and the paratype adult male, strongly suggesting that this is the normal morphology. The right pereopod 1 has the basis the same length with similar setation to the left pereopod 1, but the remaining articles in the appendage are shortened and have reduced setation relative to the left pereopod 1, suggesting that this morphology is aberrant. Since the difference between the two pereopods is distal of the basis, it is possible that the appendage was broken off at the basis-ischium articulation and the distal articles represent regeneration.