Ceratoppia offarostrata, Lindo, Zoe, 2011

Lindo, Zoe, 2011, Five new species of Ceratoppia (Acari: Oribatida: Peloppiidae) from western North America, Zootaxa 3036, pp. 1-25 : 17-20

Ceratoppia offarostrata n. sp.

Material examined. Holotype: Adult female. Canada, British Columbia, Vancouver Island, Upper Walbran Valley, 48°39’N, 124°35’W, 25 July 2005 (Z. Lindo & N.N. Winchester) from bark scraping at 16 m in western redcedar ( Thuja plicata D. Don ); deposited in the CNC, type No. 23976. Paratypes: 20 with same data as holotype. Canada, British Columbia, Vancouver Island, Pacific Rim National Park Reserve, Rainforest Trail (49°00’N, 125°37’W), 13 October 2005 (V. Behan-Pelletier), one from moss and bark at breast height on western redcedar. Paratypes deposited in the CNC, PFC, RNC, and ZLC.

Other material examined. Canada, British Columbia: Graham Island, Haida Gwaii (53°28’N, 132°25’W); Cape St. James, Gwaii Haanas National Park Reserve, Haida Gwaii (51°56’N, 131°1’W).

Etymology. The specific epithet is from the Latin “ offa ” meaning “lump”, and refers to the prominent bump on the rostrum seen in lateral view.

Diagnosis. Adult. Total length 570–640 µm, with character states of Peloppiidae ( Grandjean, 1954; as Ceratoppiidae ), and character states of Ceratoppia as described above. This species can be differentiated from other Ceratoppia by the presence of a single pair of hypostomal setae; two pairs of posterior notogastral setae conspicuous (p1, p3); rostrum rounded with many denticles but without prominent medial tooth, or indentation; rostrum in lateral view with prominent ‘bump’; lamellae with short cusps not reaching the insertion of rostral setae; interlamellar setae distinctly longer than lamellae.

Description. Adult. ( Figs. 32 –38)

Measurements: Mean total length: females (n = 6) 625 µm (range 620–640); males (n = 4) 575 µm (range 570–580) ( Figs. 32 –34). Mean notogastral width: females (n = 6) 360 µm (range 330–370); males (n = 4) 333 µm (range 310–350).

Integument: Smooth to microtuberculate. Integument laterad of bothridial setae between acetabula III and IV tuberculate. Prodorsum: Rostrum without medial tooth, dentate with five to eight teeth ( Fig. 32 , Figs. 37–38). Seta ro 80 µm long, acuminate, thick, barbed, extending well beyond rostrum (Figs. 36–38). Lamellae about 220 µm long to end of cusps, not reaching insertion of ro (Fig. 37). Lamellar cusps about 61 µm long. Seta le about 110 µm long, barbed, tapering, extending anteriorly well beyond rostrum (Figs. 36–38). Seta in barbed, 260 µm long, extending anteriorly beyond tips of lamellae (Fig. 37). Mutual distance of setal pairs ro–ro, le–le, and in–in, about 68, 60, and 77 µm, respectively. Seta ex not observed; alveoli removed anteriolaterally from bothridial. Bothridial seta 160 µm long, with long barbs (Fig. 34). Lateral aspect of prodorsum: Pedotectum I well developed, rounded and crenulate anteriorly, with dorsal cusp about 18 µm long. Prominent bump on the rostrum seen in lateral view (Figs. 37–38). Lateral ridge from base of acetabula I to base of rostrum (Fig. 38). Notogaster: Subequal length to width, (ratio l:w = 1.01:1); hysterosoma often fattened with four eggs of considerable size (about 280 µm long). Notogastral setae reduced to alveoli, except for two pairs of posterior setae. Posterior notogastral setae p1 about 55 µm long (range 48–63, n = 11), barbed; setae p3 about 46 µm long (range 40–55, n = 10) barbed ( Fig. 32 , Fig. 34).

FIGURES 34–38. Ceratoppia offarostrata n. sp., scanning electron microscope images of adult. 34, habitus, dorsal aspect, bothridial setae (bo), interlamellar setae (in), lamellar seta (le), posterior setae (p1, p3); 35, habitus, ventral aspect, posterior setae (p3), adanal setae (ad1, ad2); 36, habitus, frontal aspect, bothridial setae (bo), interlamellar setae (in), lamellar seta (le), rostral setae (ro); 37, prodorsum, dorsal aspect, interlamellar setae (in), lamellar setae (le), rostral setae (ro), and rostral bump (a); 38, rostrum, anterio–lateral aspect, showing rostral bump (a), rostral setae (ro), lamellar setae (le), and lateral carina (ca). Scale bars = 300 µm (Fig. 34, 35), 200 µm (Fig. 36), 100 µm (Fig. 37), and 50 µm (Fig. 38).

Lyrifissures im, ip, ih, and ips present, all about 8 µm long. Ventral region: Coxisternal setae smooth or with a few barbs, acuminate; formula (epimeres I to IV) 3–1–3–3 ( Fig. 33 ). Setae lengths as follows: 1a, 1b, 1c about 35, 78, 93 µm, respectively, 2a, 3a, 3b, 3c about 32, 21, 94, 21 µm, respectively, and 4a, 4b, 4c about 37, 35 and 21 µm, respectively. Six pairs of genital setae ranging in length from 18–25 µm, with longest g5 and g6, setose. Aggenital seta about 21 µm long, setose, acuminate. Two pairs of anal setae about 21 µm long, acuminate. Three pairs of adanal setae; ad3 24 µm, ad1 34 µm and ad2 30 µm, all barbed ( Fig. 33 , Fig. 35). Lyrifissure iad 8 µm long, anterior to ad3. Gnathosoma: Subcapitular mentum without tectum; one pair of h setae about 52 µm long; gnathosomal setae m 38 µm long, and a about 31 µm long.

Legs: Ratio of leg IV to body length about 0.65:1. Approximate lengths of leg segments (femur, genu, tibia, tarsus; in µm): I 143, 35, 93, 134; II 111, 27, 79, 114; III 73, 35, 94, 117; IV 75, 50, 107, 150. Pretarsus tridactylous with large smooth empodial and slightly thinner lateral claws. Setation (I–IV, number of solenidia in parentheses): trochanters 1–1–2–1; femora 5–4–3–2; genua 3(1)–3(1)–2(1)–3; tibiae 4(2)–4(1)–3(1)–3(1); tarsi 20(2)–15(2)–15– 12; setation indicated in Table 2. Seta d absent from genua and tibiae of adult, no evidence of retention associated with socket of solenidion ϕ1. Most of leg setae conspicuously barbed. Seta ft” on tarsus leg IV prominent, thick, barbed. Femur of leg III–IV with well developed ventral keel; femur leg I–II relatively slender without ventral keel, with bumpy cerategument anteriorly. Tibiae solenidion ϕ1 of leg I flagellate, anterior of ϕ2 which is straight, sharp. Leg II tarsal solenidia ω1 and ω2 subequal, straight, relatively short; tibial solenidia ϕ straight, twice as long as genua solenidia σ. Porose areas dorsolateral and antiaxial on femora of all legs, and trochanters III, IV. Single specimen with deformed right leg I tarsus.

Remarks. Ceratoppia offarostrata n. sp. and C. sexpilosa share the characteristic rostral ‘bump’, but C. offarostrata differs from C. sexpilosa in the number and expression of posterior notogastral setae. Ceratoppia offarostrata has two pairs of posterior notogastral setae (p1 and p3 expressed) versus three pairs (h1, p2, p3 expressed) in C. sexpilosa ( Hammer 1967) . Ceratoppia offarostrata also lacks a prominent medial rostral tooth; other similar species which lack medial rostral tooth include C. sphaerica and C. hoeli Thor, 1930 , but these lack the rostral ‘bump’. Ceratoppia hoeli also differs from C. offarostrata in having simple posterior seta, very short lamellar cusps, and long lamellar setae ( Thor 1930). Ceratoppia sphaerica is quite similar to C. offarostrata (two pairs of medium sized, barbed p1, p3 setae) but in addition to lacking the rostral bump, C. sphaerica is much larger in size (0.7–1.0 mm) ( Hammer 1955; Seniczak & Seniczak 2010). A full diagnosis and comparison of C. offarostrata with C. sphaerica is problematic though as the original type specimen of C. sphaerica as described by L. Koch (1879) is unknown; the original drawings and text are poor. The consensus of character states for C. sphaerica are: large body size (700–1000 um); dark (almost black) in colour; prodorsum rounded anteriorly with a serrate or dentate edge; lamellar setae longer than rostral setae; interlamellar setae as long as prodorsum, longer than lamellae; lamellae not reaching insertion of rostral setae, with short cusps; two pair, rather short posterior notogastral setae (p1 and p3) ( Trägårdh 1906; Gilyarov 1975; Hammer 1952; 1955; Seniczak & Seniczak 2010).

Distribution. Ceratoppia offarostrata n. sp. occurs in low frequency and low abundance in samples collected from the Walbran Valley on Vancouver Island, British Columbia. Specimens collected from type locality in Walbran Valley are associated exclusively with bark scraping samples on western redcedar. Similarly, specimens collected from Pacific Rim National Park, British Columbia are from moss and bark samples collected from western redcedar trees at breast height. Association with bark habitats, and the possibility of host tree specificity, may explain the low occurrence of collection for this species. The distribution range of C. offarostrata appears limited to coastal locations on Vancouver Island and Haida Gwaii. Specimens collected from Haida Gwaii have slightly shorter posterior setae and reduced rostral bump. The distributional patterns of C. sphaerica suggest this species is limited to arctic and subarctic areas in western Canada; C. offarostrata may be southern variant subspecies of C. sphaerica ; further sampling of C. offarostrata and comparison with C. sphaerica is warranted.

Figures

FIGURES 32 – 33. Ceratoppia offarostrata n. sp., adult female. 32, dorsal aspect; 33, ventral aspect. Legs removed. Scale bars = 300 µm.