Politolana haneyi, Riseman & Brusca, 2002

Riseman, Sarah F. & Brusca, Richard C., 2002, Taxonomy, phylogeny and biogeography of Politolana Bruce, 1981 (Crustacea: Isopoda: Cirolanidae), Zoological Journal of the Linnean Society 134 (1), pp. 57-140 : 85-86

Description of P. haneyi n.sp.

( Figs 16–21 )

Holotype. Male, 13.5 mm long, USNM # 288401

Type locality. Guaymas Basin , Gulf of California.

Paratypes. USNM # 288402–2888403 : Guaymas Basin , Gulf of California; 20 females, 11 males, 3 mancas .

Additional material examined. Series of specimens from Gulf of Mexico, 29°06 N, 88°28 W, 311 m, 11°C, 2 August 1987 — GCRL # 1361 : 9 males, 7 females, 4 juveniles. GCRL # 1366 : 50 + spec. USNM # 211890 : off FL, 26°16.53 N, 84°05.97 W, 146 m, col. by Mml for BLM, trawl sta. 33, 7 July 1981; 1 female. USNM # 236181 : off Sombrero Light , FL, 92–110 m, col. by Thompson & Mcginty, R/V Triton, 6 June 1950; 2 females.

Diagnosis. Body highly vaulted, pereon and pleon convex and tightly articulated. Coxae 4–6 narrow, with oblique impressions. Cephalon anterior margin medially straight, without rostral point; lateral margins of raised frontal ridge extending over and dividing eyes. Eyes large, round, darkly pigmented. Interocular furrow complete. Antennae reaching middle of second pereonite. Pereopods 1–3 ischium and merus superior distal angles greatly produced, with meral lobe reaching midpoint of propodus; inferior margin of merus with row of long acute robust setae. Merus and carpus of pereopods 4–6 with robust setae arranged in transverse rows on posterior face. Ischium superior margin with sparse simple setae; P5–P7 posterior distal margin of ischium with studded-biserrate setae. Pereopod 7 superior distal angle of merus with long slender plumose setae. Uropod endopod apex narrowly subacute, with distomedial margin slightly concave; apex with cluster of long simple setae. Exopod shorter than endopod peltate in shape, apex with large robust seta, two smaller robust setae and a cluster of long simple setae. Pleotelson posterior margin convex with PMS and four small robust setae.

Description of holotype. Male, 13.5 mm long; body length about 4 Ⅹ width. Pereon cuticle highly polished; cream colour in alcohol without any apparent chromatophores or pigmentation.

Cephalon: Polished, without strong minute punctation. Anterior margin medially straight without rostral point; lateral margins of raised frontal ridge extending over and dividing eyes. Interocular furrow complete. Eyes large, round, darkly pigmented; cuticular ommatidial facets absent. Frontal lamina narrow, length about 4.5 Ⅹ greatest width, reaching middle of antennule peduncles, with slight hourglass shape. Frontal lamina and clypeus with lateral margins raised as thickened ridges.

Antennule: Peduncle articles with short simple and palmate setae on distal angles; peduncle article 3Ⅹ longer than wide. Flagellum composed of 11 articles, each with 4–6 aesthetascs; first flagellar article longest, with length subequal to width; width of subsequent articles about twice length.

Antenna: Reaching middle to end of second pereonite. Peduncle articles 3–5 progressively longer; article 3 length subequal to width, widening distally; article 4 longer than wide, narrowing distally, posterior distal angle bearing four long stiff simple setae and some short palmate setae; article 5 narrow, approximately 3Ⅹ longer than wide, with width about half the basal width of article 4, posterior distal angle bearing 1–3 long stiff simple setae and several short palmate setae. Flagellum composed of 20 articles, subquadrate proximally, lengthening distally.

Mandible: Molar process dorsal surface covered with fine setae arranged into small shingle-like rows; spines on anterior margin widely spaced, not touching at their bases; submarginal setal row with approximately 13 long lightly plumose setae extending from proximal cluster.

Maxilliped: Endite with distal cluster of three robust circumplumose setae; right and left endites with two coupling hooks.

Pereon: Body highly vaulted. Medially, pereonite 1 longest, 2 shortest, 3–7 subequal in length, with 5 and 6 slightly longer; in dorsal aspect. Pereonite 1 narrows markedly to encompass cephalon; with impression along lateral margin and a small, faint oblique impression on mid-lateral surface, anterolateral margins straight forming blunt anterior angles. Coxae 2 and 3 with impression parallel to lateral margin; coxae 4–6 narrow, posterior margins oblique with acute posterior angles, progressively more extended posteriorly, with distinct oblique impressions; coxae 7 length subequal to coxae 6, without oblique impressions, posterior angle acute.

Pleon: Pereonite 7 overlapping anterior portion of first pleonite. Cuticle less polished than pereon; dorsoventrally vaulted similar to pereon. Epimeres ventrally, but not laterally produced, only 1 and 4 posteriorly produced; epimeres 2–4 bearing dense lateral setal fringe. Ventral flanges with ventral posterior angles rounded.

Pereopods 1–3: Basis superior submarginal setal row with fewer than 10 setae, with 6–7 stout circumplumose setae on superior margin. Ischium posterior face with two oblique rows of stout simple setae; superior distal angle produced into large scoop-shaped lobe. Merus superior distal angle produced into large recurved lobe reaching midpoint of propodus, with one (P1) or two (P2 and P3) apical setae slightly more robust than adjacent setae; inferior margin of merus with row of long acute robust setae and adjacent row of short acute robust setae. Ischial and meral lobes of P1–P3 progressively less produced. Carpus of P2 and P3 subquadrate. Distal superior margin of propodus with short row of simple setae. Dactyl length less than propodal length.

Pereopods 4–6: Ischium superior margin with sparse simple setae; posterior distal margin with studdedbiserrate setae (absent on P4). Posterior face of merus and carpus with robust setae in short transverse rows or clusters extending from inferior margin, progressively less setose posteriorly. Carpus narrow, 2–3Ⅹ longer than wide, lengthening posteriorly. Pereopod 6 distal angles of merus and carpus with long distally biserrate setae; propodus inferior margin with short acute distally biserrate setae, and with a robust studded-serrate seta on inferior distal angle.

Pereopod 7: Like P6 except: slightly shorter; superior distal angle of merus with long slender plumose setae, long slender distally biserrate setae, and short acute robust setae. Carpus distal margin expanded, about 2–3Ⅹ as wide as proximal propodal width; propodus length subequal to carpus length.

Pleopods: Pleopod 1 peduncle subquadrate, with six plumose coupling hooks; endopod width about one-half of exopod width. Pleopod 2 peduncle with four plumose coupling hooks; appendix masculina narrow, of relatively constant width, tapering evenly to slightly curved apex; reaching or extending slightly beyond exopod apex. Pleopods 3 and 4 with four plumose coupling hooks.

Uropod: Peduncle medial production distally acute, with five long plumose setae. Endopod apex narrowly subacute, with distomedial margin slightly concave; apex with cluster of long simple setae, flanked by two short robust setae; distal margin with three additional smaller robust setae and PMS. Exopod shorter than endopod, flat, with lateral margins slightly convex, apex with large robust seta, two smaller robust setae, and a cluster of long simple setae; distal lateral margin with a small robust seta.

Pleotelson: Posterior margin evenly convex, with PMS and four small robust setae.

Variation. While not present in the holotype, some animals have a distinct distal patch of fine setae on the mandible molar process, as in P. impressa . The length of antennule peduncle article 3 ranges from subequal to the width to longer than wide. The antenna has 19–22 flagellar articles. Maxilliped endites have one or two coupling hooks, typically two. The oblique impression on the lateral face of the first pereonite ranges from absent to well developed.

Sexual dimorphism. Males are typically smaller than females, with the largest males only slightly larger than the smallest females.

Remarks. This species is very similar to P. impressa ; however, it can easily be distinguished by the vaulted or dorso-ventrally convex form of the pleon and the form of the uropod endopod.

Etymology. This species is named for Todd Haney, good friend and fellow crustacean biologist.

Distribution. An amphi-American subtropical species known from the Gulf of California and the northern Gulf of Mexico. Politolana haneyi is found in the same locality as P. impressa and P. wickstenae in the Gulf of Mexico, but in shallower waters between 92 m and 311 m. We know that the Gulf of California sample was collected in the Guaymas Basin, but lack any other collection locality information including the depth of collection. See the biogeography section for a discussion of the amphi-American nature of this species.

Figures

Figure 16. Politolana haneyi male holotype: (A) lateral aspect; (B) dorsal aspect; (C) antennule; (D) penes; (E) frontal lamina; (F) antenna.

Figure 17. Politolana haneyi male holotype: (A) right maxilliped; (B) maxilla; (C) right mandible; (D) maxillule.

Figure 18. Politolana haneyi male holotype: (A–C) pereopods 1–3, respectively.

Figure 19. Politolana haneyi male holotype: (A–C) pereopods 4–6, respectively.

Figure 20. Politolana haneyi male holotype: (A) pereopod 7; (B) right uropod.

Figure 21. Politolana haneyi male holotype: (A–E) pleopods 1–5, respectively.