Colurostylis whitireia Gerken, 2015, n. sp.
Creators: name: Gerken, Sarah
Publisher: name: Zenodo
Year: 2015
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Cumacea
Diastylidae
Colurostylis
Colurostylis whitireia

description: Colurostylis whitireia n. sp.
(Figs. 1–5)
Material examined. Holotype: ovigerous female, NIWA 0 94659, Te Onepoto Bay, Whitireia Park, Porirua, 41.1088°S, 178.8558°E, 0–1 m, 19 February 2011. Paratypes: preparatory female (dissected), NIWA 094661; adult male (dissected), NIWA 094663; two subadult males, NIWA 094660; Te Onepoto Bay, Whitireia Park, Porirua, 41.1088°S, 178.8558°E, 0–1 m, 19 February 2011.
Diagnosis. Female and subadult male. Carapace with 2 oblique ridges, anterolateral corner not serrate. Pseudorostrum acute. Eyelobe without lenses. Antennule peduncle of 2 articles. Uropod peduncles shorter than pleonites 5–6 together, exopod longer than endopod.
Adult male. Carapace with single oblique ridge. Pseudorostrum blunt. Eyelobe with lenses. Antennule peduncle of 2 articles, with small brush of setae. Antenna extending past posterior border of telson. Telson with pair of slender plumose subterminal setae.
Etymology. The species is named whitireia for the locality of collection, Te Onepoto Bay within Whitireia Park, Porirua, New Zealand; used as a noun in apposition.
Description. Ovigerous female holotype 3.2 mm, preparatory female paratype 2.1 mm. Body (Figs. 1 A–B). Carapace with 2 strong oblique ridges, antennal notch oblique; eyelobe broad, without lenses; pseudorostrum acute. Pleon unornamented.
Antennule (Fig. 2 A) with 2 peduncle articles; article 1 unarmed, longer than article 2; article 2 with few simple setae. Main flagellum of 3 articles, longer than peduncle article 2, with 2 aesthetascs and few simple setae distally; accessory flagellum of 2 articles, shorter than article 1 of main flagellum, with few simple setae.
Antenna (Fig. 2 B) of 3 articles, with plumose setae terminally.
Mandibles (Fig. 2 C) navicular, lacinia mobilis with 3 cusps, with row of 9 microserrate setae medially.
Maxillule (Fig. 2 D) with 2 endites; palp with 2 microserrate setae.
Maxilla (Fig. 2 E) with 3 endites; broad endite medial row of setae simple; narrow endites with short simple setae.
Maxilliped 1 (Fig. 2 F) carpus without beak setae, with simple setae medially; without long plumose setae.
Maxilliped 2 (Fig. 2 G) ischium visible.
Maxilliped 3 (Fig. 2 H) 100:9:16:13:17:13; basis produced distolaterally with 3 plumose setae; ischium unarmed; exopod fully developed.
Pereopod 1 (Fig. 2 I) 100:15:19:37:43:35; dactylus with long, simple setae terminally.
Pereopod 2 (Fig. 2 J) 100:4:29:31:24:45; exopod longer than basis.
Pereopod 3 (Fig. 3 A) 100:14:25:20:17:12; ischium, merus, carpus and propodus with annulate setae; dactylus terminal seta microserrate; rudimentary exopod 0.34 times basis length.
Pereopod 4 (Fig. 3 B) 100:18:40:33:25:18; ischium, merus, carpus and propodus with annulate setae; dactylus terminal seta microserrate; rudimentary exopod 0.48 times basis length.
Pereopod 5 (Fig. 3 C) 100:16:39:58:23:23; basis, ischium and merus with plumose setae; carpus and propodus with annulate setae; dactylus terminal seta microserrate.
Telson (Fig. 3 D) unarmed, half as long as pleonite 6.
Uropods (Fig. 3 D) peduncles with simple setae with a single setule medially; endopod biarticulate, with few simple setae with single setule medially, stout simple seta with single
setule terminally; exopod longer than endopod, with long simple setae.
Adult male paratype 2.3 mm. Body (Figs. 1 C–D). Carapace with single oblique ridge, antennal notch oblique; eyelobe broad, with 3 lenses; pseudorostrum blunt. Pleon unornamented.
Antennule (Figs. 4 A–B) with 2 peduncle articles; article 1 with plumose seta, more than twice as long as article 2; article 2 with few simple setae. Main flagellum of 6 articles, basal article expanded with many simple setae, with 2 aesthetascs terminally; accessory flagellum of 3 articles, as long as first two articles of main flagellum, with simple setae terminally.
Antenna (Figs. 4 C–D) peduncle with brush of setae on article 5; flagellum extending past telson, of 21 articles.
Mandibles – maxilliped 2 not examined.
Maxilliped 3 (Fig. 4 E) 100:6:12:12:15:11; basis medial margin toothed distally, produced at distolateral corner with 3 plumose setae; exopod basal article twice as wide as flagellum.
Pereopod 1 (Fig. 4 F) 100:7:18:23:32:23; dactylus with simple setae terminally; exopod basal article three times as wide as the flagellum.
Pereopod 2 (Fig. 5 A)100:3:17:32:13:25; exopod basal article at least three times as wide as flagellum.
Pereopod 3 (Fig. 5 B)100:8:21:15:11:11; basis with plumose, pappose and pedunculate setae; ischium, merus, carpus and propodus with annulate setae; dactylus terminal seta simple; exopod basal article at least three times as wide as flagellum.
Pereopod 4 (Fig. 5 C)100:7:23:23:12:12; basis with plumose, simple and annulate setae; merus, carpus and propodus with annulate setae; dactylus terminal seta simple; exopod basal article at least three times as wide as flagellum.
Pereopod 5 (Fig. 5 D)100:9:33:30:12:15; basis with plumose setae; ischium, merus, carpus and propodus with annulate setae; dactylus terminal seta simple.
Pleopod 1 (Fig. 5 E) biramous, with plumo–annulate setae.
Pleopod 2 (Fig. 5 F) biramous, with plumo–annulate setae, shorter than pleopod 1.
Telson (Fig. 5 G) with 2 small plumose setae inserted subterminally, shorter than pleonite 6.
Uropods (Fig. 5 G) peduncles with microserrate setae with long setule medially; endopod biarticulate, article 2 much longer than article 2, with many microserrate setae with long setule medially, terminal seta stout with single setule; exopod longer than endopod, with simple setae.
Distribution. Te Onepoto Bay, Whitireia Park, Porirua, New Zealand, 0– 1 m.
Remarks. This species is unique within the Cumacea in having a 2 article peduncle on the antennule. This character is identical in the male and female specimens examined, and is clearly not an aberration. This state represents either a fusion of two articles or a loss of an article on the peduncle. There is a geniculation about midway in the first article which may represent a site of fusion between two articles.
The most similar species of Colurostylis is C. lemurum, which also has oblique ridges on the carapace. However, C. lemurum has 3 articles in the antennule peduncle, and the uropod endopod is longer than the exopod, unlike C. whitireia with 2 articles in the antennule peduncle and the uropod exopod longer than the endopod.
description: Published as part of Gerken, Sarah, 2015, New Zealand Diastylidae and Gynodiastylidae (Crustacea: Cumacea), pp. 1-77 in Zootaxa 4031 (1) on pages 8-14, DOI: 10.11646/zootaxa.4031.1.1, http://zenodo.org/record/289704