Caleremaeus nasutus, Norton & Behan-Pelletier, 2020

Norton, Roy A. & Behan-Pelletier, Valerie M., 2020, Two unusual new species of Caleremaeus (Acari: Oribatida) from eastern North America, with redescription of C. retractus and reevaluation of the genus, Acarologia 60 (2), pp. 398-448 : 426

Caleremaeus nasutus n. sp.

Zoobank: 38F837A3-7D6C-4D2C-B339-D4183DA29EBB

Etymology — The Latin species epithet ‘nasutus’ is an adjective referring to the large nose-like anterior lobe of the prodorsum.

Material examined — Holotype and 13 paratype adults from: USA, Alabama, Randolph Co., State Route 48, ca. 1 km east of Woodland (33° 22.8 ஥ N, 85° 23.4 ஥ W);, 3.xii.1980, R.A. Norton col., from litter layer in young shortleaf pine ( Pinus echinata Mill. ) and mixed-oak ( Quercus spp.) forest. Other material: Another 75 paratype adults are from Alabama, Lee Co., near Auburn, 7.xi.1975 (collector unknown), from litter in loblolly pine ( Pinus taeda Linn. ) forest. Holotype and 10 paratypes deposited in USNM; 15 paratypes in CNC, remainder in RNC.

Diagnosis — Caleremaeus species with adults having total length 284–348 µm. Prodorsum without cusp or distinct lamella; lamellar setae inserted on large, hollow, tongue-shaped anterior lobe; tutorium weakly developed, enantiophysis eA present; usually with single small pair of dorsosejugal tubercles. Notogastral setae small (mostly ~ 10–15 µm), most barbed and curled beyond basal cerotegument nodule. Epimeral groove 2 without bordering tubercles or knots; ventrosejugal groove with only simple enantiophysis eS. Genital setation variable; females usually with five, males with 4–6 setae on each plate. Leg femora each with porose area. Juveniles unknown.

Adult

Figures 13–17

Dimensions — Total length of 20 paratypes 284–348 µm (mean 326); maximum width 162–196 µm (mean 180). Female (n = 10) length 336–348 µm (mean 342), maximum width 186–196 µm (mean 191); male (n = 10) length 284–323 µm (mean 309), width 162–181 µm (mean 169).

Integument, setae — Cerotegument excrescences mostly in form of dome- to mushroomshaped or near-spherical excrescences, but partly irregular in form ( Figs 14 , 16A, B, H ); largest on notogaster (mostly 3–5 µm diameter), smallest (1–2 µm) on venter where microgranules cover and fill intervening space ( Fig. 14 C–D). Dorsal setae (except bs) short, inconspicuous, acute to acuminate; basal third hyaline, birefringent, smooth, straight, surrounded by distinct and usually shaded cerotegument nodule; distal region isotropic, pigmented, curved to curled, with minute barbs on outer curvature ( Fig. 16A, B, D ), sometimes pulled away during preparations ( Fig. 16C ). Ventral setae (except adanal series) simple, nearly straight, without pigment or distinct basal cerotegument nodule.

Figures

Figure 13 Caleremaeus nasutusn. sp., adult: A – dorsal view (legs mostly omitted); B – ventral view (legs omitted). Scale bar: 50 µm.

Figure 14 Caleremaeus nasutusn. sp., scanning electron micrographs of adult: A – dorsal view cerotegument broken from central region of notogaster; B – ventral view, with enlargement of preanal region in upper right (* indicates location of C); C – fractured cerotegument on ventral plate; D – subcapitulum and surrounding region, ventral view; E – bothridial region, anterior view; F – proterosoma, anterior view. Scale bars: 50 µm (A, B); 10 µm (D-F); 2 µm (C).

Figure 15 Caleremaeus nasutusn. sp., transmitted-light micrographs of adult: A – prodorsum, dorsal view; B – anterior prodorsal lobe, different specimen; C – posterior prodorsum and sejugal region, dorsal view; D – bothridial seta; E – prodorsum, lateral view (gnathosoma removed); F – optical section of E, focused near midline; G – optical section of rostrum, anterior to top, dorsal view, focused on embossed figure on inner face of rostral bulge; H – same, different specimen, anterodorsal view of dissected fragment (rostrophragma broken on left). Scale bars: 20 µm (A-E); 10 µm (F-H).

Figure 16 Caleremaeus nasutusn. sp., transmitted-light micrographs of adult: A – end of posterior notogastral bulge, region of setal pair h1, dorsal view (insert = h1from another specimen, arrow to basal cerotegument nodule); B – posterolateral contour of notogaster, dorsal view; C – notogastral seta la, entire (above) and with isotropic outer layer removed leaving only birefringent core; D – posterior contour of notogaster, ventral view (left p1 and p2 lost, leaving only basal cerotegument nodule; insert = enlargedp1); E – coxisternum, ventral view (arrowhead on projection at end of discidial ridge); F – region above legs III-IV, lateral view (arrowhead as for F); G – preanal organ, optical section; H – region of aggenital enantiophysis. Scale bars: 10 µm (A-F, H); 5 µm (G).

Figure 17 Caleremaeus nasutusn. sp., transmitted-light micrographs of adult: A – legs I-IV, abaxial view (trochanter II not shown); B – femur II (cerotegument mostly separated; insert = seta d of femur I); C – tibia and tarsus I; D – chelicera, abaxial view. Scale bars: 20 µm (A); 10 µm (B-D).