Excelsotarsonemus caravelis Rezende, Lofego & Ochoa

Rezende, Jose Marcos, Lofego, Antonio Carlos, Ochoa, Ronald & Bauchan, Gary, 2015, New species of Daidalotarsonemus and Excelsotarsonemus (Acari, Tarsonemidae) from the Brazilian rainforest, ZooKeys 475, pp. 1-36 : 11-16

Taxon classification Animalia Trombidiformes Tarsonemidae

Excelsotarsonemus caravelis Rezende, Lofego & Ochoa sp. n. Figs 15, 16, 17, 18, 19, 20, 21

Diagnosis.

Females of this species resemble those of Excelsotarsonemus kimhansenae Ochoa & OConnor because of the shape of dorsal setae v1, sc2, c1 and c2, and the ornamentation pattern on the prodorsum; but they are distinguished by the asymmetric shape of setae e and the U-shaped cerotegument accumulation between prodorsum and tergite C in Excelsotarsonemus caravelis sp. n., whereas setae e are orbicular and smooth and tergite C surface is smoother in Excelsotarsonemus kimhansenae . The accumulation of the cerotegument between the tergites was easily noticed in all microscopy techniques used (Fig. 16), and it is being considered a taxonomic feature, useful for distinguishing these species.

Adult female

(5 specimens measured). Gnathosoma (Figs 17, 20, 21A-B): completely covered by prodorsum. Subtriangular in ventral view, length 22 (21-24), maximum width 17 (16-19); dorsal apodeme distinct. Setae dgs 7 (7-8) and vgs 5 (5-6) smooth; palps moderately short 6-8 (7), with 2 small subterminal setae and terminal projections. Pharynx fusiform, 15 (15-16) long and 6 (6) wide at maximum width. Gnathosoma, idiosoma and legs covered with tiny dimples, each 0.3 (0.2-0.5) in diameter.

Idiosoma - dorsum (Figs 15-16): length 167 (166-168), width at level of c1 86 (84-90); prodorsal shield normally covering entire gnathosoma, with three external humps, broader proximally, central area with an inverted Y-shaped pattern. Stigma near lateral notch of the prodorsal shield, equidistant to the v1 and sc2 setal bases. Entire dorsum covered with cerotegument with a U-shaped cerotegument accumulating between the prodorsum and tergite C (Fig. 16). Tergite D with irregular bumps near setae d. Lengths of the setae: v1 29 (27-31), sc1 16 (14-18) (Fig. 21C), sc2 47 (45-49), c1 40 (40-41) (Fig. 21E), c2 9 (8-10), d 30 (28-32) (Fig. 21F), e 16 (16-17), f 36 (35-38) and h 13 (11-16). Maximum width of expanded setae: sc2 3 (3-4), c1 11 (11-12), d 22 (21-23), e 32 (31-33) and f 12 (11-13). All setae serrate, except for c2 which is smooth. Bothridial setae sc1 capitate with tiny spines; sc2 linear with a strong central furrow; setae c1 lanceolate, d ovate and f oblanceolate with serrate central veins; e each totally asymmetric (Figs 21G-H). Distances between dorsal setae: v1-v1 26 (24-29), sc2-sc2 46 (45-48), v1-sc2 15 (14-16), c1-c1 43 (41-45), c2-c2 89 (85-96), c1-c2 36 (34-38), d–d 27 (27-28), f–f 11 (9-13), e–f 12 and h–h 5 (4-7). Seta sc2 located anteriorly to sc1. Dorsal cupules not easily seen.

Idiosoma - venter (Figs 17-18): seta 1 a 6 (6-7), posteriad of apodemes 1; 2a 9 (9-10), posterolaterad of apodemes 2; 3a 11 near anteriomedial margins of apodemes 3; 3b 8 (8-9) on posterior margins of apodemes 4. Apodeme 1 conspicuous and fused to anterior end of prosternal apodeme. Apodeme 2 short and not fused to prosternal apodeme. Prosternal apodeme conspicuous from junction with apodeme 1 near middle of sejugal apodeme portion. Sejugal apodeme uninterrupted with several small indentations. Apodeme 3 with a constriction near anterior end, extending diagonally from proximity of base of seta 3a to anterior margin of trochanter III; apodeme 4 extending diagonally from the middle of the poststernal apodeme to base of seta 3b. Poststernal apodeme bifurcated anteriorly. Tegula wide 16 (15-17) and very short, 4 (4-5) (Fig. 21I), posterior margin slightly arched. Setae ps 17 (16-19) smooth.

Legs (Fig. 19): lengths (measured from femur to tarsus): leg I 42 (42-43), leg II 40 (39-41), leg III 92 (89-95), leg IV 32 (31-35). Number of setae (solenidia in parentheses) on femur, genu, tibia and tarsus, respectively: leg I: leg I: 3-4-5(2)-7(1), leg II: 3-3-4-4(1), leg III: 2+2-4-4. Claws medium-sized (not reduced) and hooked. Empodia of the legs I, II and III about the same size or slightly smaller compared to the respective basal stalks. Tarsal solenidion ω of tibiotarsus I 4 (4-5), stout, wider medially. Sensory cluster of tibia I complete (Fig. 21D), solenidion φ 1 4 (4-5), slender, capitate; solenidion φ 2 3, robust, slightly capitate; famulus k 6; all those inserted at approximately in the same level. Seta d of tibia I 23 (22-24), serrate. Solenidion ω of tarsus II proximally inserted, 4 long, stout, wider medially. Seta d of tibia II 17 (17-18), serrate. Femorogenu IV 18 (16-20); tibiotarsus IV 9 (9-10). Length of leg IV setae: v’ F 8 (8-9), v’ G 10 (10-11), v’ Ti 23 (22-24) and tc" 31 (29-33); setae v’ Ti and tc" smooth; v’ Ti falcate.

Adult male.

Unknown.

Type material.

Holotype female and 4 paratype females on Theobroma cacao L., 14°47'45"S; 39°10'18"W, Ilhéus, State of Bahia, Brazil, 10/IX/2012, A.C. Lofego and J.M. Rezende. Holotype and 3 paratypes are deposited in the DZSJRP and 1 paratype is deposited in the USNM.

Etymology.

The region where this mite was found is the same place as the first Portuguese explorers arrived in Brazil, at the end of 15th century. On their trip, they used caravels, which had big sails. The name caravelis is used because several dorsal setae of this mite species are held in the upright position resembling those sails.

Note.

Setae f has a unique modification as it is oblanceolate dorsal view, with four faces attached by the main vein, giving a deep concavity at either site, with a central furrow dorsally shoe-like; all margins serrate (Fig. 21H). Similar setal complex modification has been observed in Excelsotarsonemus mariposa (setae d, f and e) and other Excelsotarsonemus and Daidalotarsonemus species under DIC. However, it is under the LT-SEM that we can understand their complexity.