Hydrogamasellus alagoensis, Santos, Jandir C., Castilho, Raphael C., Silva, Edmilson S. & De Moraes, Gilberto J., 2013

Santos, Jandir C., Castilho, Raphael C., Silva, Edmilson S. & De Moraes, Gilberto J., 2013, A new species of Hydrogamasellus (Acari: Mesostigmata: Ologamasidae) from Brazil, with a key to the world species of the genus, Zootaxa 3718 (1), pp. 81-88 : 82-85

Hydrogamasellus alagoensis n. sp.

Material examined. Holotype female, six paratype females and two paratype males from litter at the base of Tapirira guianensis Aublet. (Anacardiaceae) at Teotônio Vilela (09°56'19.5"S and 36°22'17.1"W), State of Alagoas, Brazil, November 15, 2011. All types collected by J.C. Santos and deposited at Departamento de Entomologia e Acarologia, Escola Superior de Agricultura “Luiz de Queiroz” (ESALQ), Universidade de São Paulo (USP), Piracicaba, State of São Paulo, Brazil.

Adult female ( Fig. 1–7 ) (five specimens measured).

Gnathosoma. Fixed cheliceral digit 110 (109–111) long, with six teeth in addition to apical tooth and a setiform pilus dentilis ( Fig. 1 ); movable cheliceral digit 106 (104–109) long, with three teeth in addition to apical tooth; antiaxial and dorsal lyrifissures as well as dorsal seta distinct. Arthrodial process of chelicera a short coronetlike fringe. Palp chaetotaxy (trochanter to tarsus): 2-5-6-14 -15; apotele 3-tined; setae aciculate and smooth or slightly pilose, except al 1 of palp genu pectinate with 6–7 lateral prongs ( Fig. 2 ). Epistome with an anteromedian extension wider at the base and acute distally, with one to several pairs of lateral denticles. ( Fig. 3 ). Deutosternal denticles in eight rows; anterior row “V” shaped, other rows straight and transverse; first seven rows with 8–12 denticles each, delimited by lateral lines of deutosternum; eighth row with 18 denticles, extending beyond the lateral lines; with an additional basal most row of 5–9 pairs of denticles, all outside deutosternum ( Fig. 4 ). Internal malae totally separated from each other; each laterally fimbriate. Seta h 3 about in longitudinal line with h 1 and slightly anterior and mediad to h 2. Measurements of setae: h 1 50 (49–52), h 2 37 (35–40), h 3 47 (45–50), sc 37 (35– 40); all setae aciculate and smooth.

Dorsal idiosoma ( Fig. 5 ). Idiosoma 640 (620–660) long and 421 (405–437) wide at widest point. Podonotal and opisthonotal shields totally fused; extending laterally, so that the margin of the dorsal shield is visible ventrally; mostly imbricate, except for a transverse band anterior to s 2 and for the central region of podonotal region. Podonotal region with 21 pairs of setae (s 1, r 1 and r 6 absent) and seven pairs of distinguishable lyrifissures (including a ventrolateral pair next to region between coxae II and III). Opisthonotal region with 19 pairs of setae (R 5 absent) and six pairs of distinguishable lyrifissures. Measurements of setae: j 1 48 (47–50), j 2 50 (49–51), j 3 49 (47–52), j 4 48 (47–48), j 5 44 (40–48), j 6 46 (44–48), z 1 42 (40–44), z 2 27 (24–29), z 3 50 (50–51), z 4 54 (53–55), z 5 45 (45–46), z 6 46 (44–47), s 2 21 (20–22), s 3 27 (25–28), s 4 54 (52–55), s 5 44 (42–45), s 6 53 (53–54), r 2 15 (15–16), r 3 78 (76–80), r 4 11 (10–12), r 5 11 (10–11), J 1 48 (47–50), J 2 44 (43–45), J 3 45 (41–48), J 4 45 (45–46), J 5 49 (47–51), Z 1 52 (51–53), Z 2 53 (50–56), Z 3 50 (49–51), Z 4 53 (51–54), Z 5 58 (56–61), S 1 47 (43–51), S 2 55 (51–60), S 3 55 (51–60), S 4 57 (55–60), S 5 55 (53–58), R 1 16 (15–17), R 2 17 (15–19), R 3 15 (14–15), R 4 15 (14– 16); all setae spatulate and with distal half pilose, except z 1, z 2, s 2, r 2, r 4, r 5 and R 1- R 4 aciculate and smooth or slightly pilose.

Ventral idiosoma ( Fig. 6 ). Base of tritosternum 49 (46–52) long and 11 (11–12) wide proximally ( Fig. 7 ); laciniae 100 (100–101), totally separated and pilose; its base located between a pair of reticulate presternal shields. Sternal shield striate laterally, smooth elsewhere; 113 (112–115) long at mid-line and 170 (167–172) wide between coxae II and III, posterior margin concave; with four pairs of setae and four pairs of lyrifissures; not fused with endopodal platelet laterad of coxae III and IV. Genital shield striate laterally, smooth elsewhere; posterior margin truncate but with rounded posterior corners; as long as wide, extending posteriorly to coxae IV; distance between st 5 93 (85–100). Unsclerotised integument posterolaterad of st5 with a pair of lyrifissures. Ventrianal shield imbricate 271 (267–275) long at mid-line and 325 (312–337) wide at widest level, not fused to dorsal shield; with eight pairs of setae (Jv 1– Jv 5 and Zv 1– Zv 3) in addition to circum-anal setae [one specimen with an unpaired seta posterior to Jv 1] and three pairs of distinguishable lyrifissures. Peritreme extending anteriorly to level of coxa I. Peritrematic shield fused anterolaterally to dorsal shield and posteriorly to exopodal shield near coxa IV; with two pairs of lyrifissures and one pore posterior to stigma. Exopodal shield fragmented into a tri-radiate fragment between coxae I and II, a sinuate fragment between mid levels of coxae II and III, and an elongate fragment between coxae III and IV barely connected to peritrematic shield. Metapodal platelet indistinct. Spermathecal ringed tube opening distally on dorsal surface of coxa IV. Measurements of setae: st 1 35 (32–38), st 2 32 (30–33), st 3 29 (28–31), st 4 30 (27–33), st 5 33 (30–35), Jv 1 29 (27–31), Jv 2 32 (30–34), Jv 3 31 (30–33), Jv 4 26 (25–27), Jv 5 46 (44–48), Zv 1 30 (28–32), Zv 2 32 (30–33), Zv 3 17 (15–19), para-anal 39 (39–40), post-anal 42 (39–45); unpaired seta posterior to Jv 1 26; all setae aciculate and smooth or slightly pilose, except Jv 5, para-anal and postanal spatulate and with distal half pilose.

Legs. Lengths: I: 649 (638–660); II: 480 (460–500); III: 440 (430–450); IV: 602 (595–610). Numbers of setae on legs I–IV: coxae: 2, 2, 2, 1; trochanters: 6, 5, 5, 5; femora: 13, 11, 6, 6; genua: 13, 11, 9, 10; tibiae: 14, 10, 8, 10; tarsi (II–IV): 18, 18, 17. Setae aciculate and smooth, or spatulate and with distal half pilose. Pretarsi I–IV similar in shape, an elongate ambulacral stalk, a pair of prominent claws and three rounded pulvillar lobes; pretarsus I about half as long as other pretarsi.

Adult male ( Fig. 8–11 ) (two specimens measured).

Gnathosoma. Fixed cheliceral digit (82–88) long, with five teeth in addition to apical tooth; pilus dentilis not distinguishable ( Fig. 8 ); movable cheliceral digit (85–90) long, with one tooth in addition to apical tooth; spermatodactyl (100–101) long, about uniformly arched and with distal half spatulate; antiaxial and dorsal lyrifissures as well as dorsal seta distinct. Epistome with an anteromedian extension wider at the base and bifurcate distally, with three to several pairs of lateral denticles ( Fig. 9 ). Arthrodial process of chelicera, palp chaetotaxy, apotele, deutosternum and position of hypostomal setae as in adult female. Measurements of setae: h 1 (45–47), h 2 (40–45), h 3 (45–46), sc (45–46); shape of setae as in adult female.

Dorsal idiosoma. Idiosoma (587–612) long and (402–445) wide at widest point; dorsal shield similar to that of adult female. Measurements of setae: j 1 (45–46), j 2 (50–52), j 3 (52–53), j 4 (48–49), j 5 (43–44), j 6 (47–48), z 1 (40– 41), z 2 (20–21), z 3 (57–59), z 4 (60–62), z 5 (50–52), z 6 (50–52), s 2 (18–20), s 3 (23–29), s 4 (51–58), s 5 (40–45), s 6 (56–57), r 2 (13–14), r 3 (70–77), r 4 (9–10), r 5 (10–11), J 1 (43–45), J 2 (40–43), J 3 (40–42), J 4 (42–45), J 5 (44– 49), Z 1 (60–62), Z 2 (50–52), Z 3 (47–48), Z 4 (49–51), Z 5 (51–60), S 1 (43–47), S 2 (48–55), S 3 (51–57), S 4 (53–57), S 5 (52–58), R 1 (14–15), R 2 (13–14), R 3 (16–17), R 4 (16–17); shape of setae as in adult female.

Ventral idiosoma ( Fig. 10 ). Base of tritosternum (24–25) long and (11–12) wide proximally; laciniae (90– 100), totally separated and pilose; its base located between a pair of reticulate presternal platelets. Sternogenital shield striate anterolaterally, smooth elsewhere; (217–225) long and (170–180) wide between coxae II and III, posterior margin truncate; with five pairs of setae and four pairs of lyrifissures. Ventrianal shield imbricate; (270– 275) long at mid-line and (310–340) wide at widest point, fused with peritrematic shield; with eight pairs of setae (Jv 1– Jv 5 and Zv 1– Zv 3) in addition to circum-anal setae and four pairs of distinguishable lyrifissures. Peritreme extending anteriorly to level of coxa I. Peritrematic shield fused anterolaterally to dorsal shield and posteriorly to exopodal shield near coxa IV and to ventrianal shield; with two pairs of lyrifissures and one pore posterior to stigma. Exopodal shields as in adult female. Measurements of setae: st 1 (42–45), st 2 (30–32), st 3 (26–28), st 4 (26– 28), st 5 (30–31), Jv 1 (31–33), Jv 2 (30–35), Jv 3 (30–33), Jv4 (30– 31), Jv 5 (45–46), Zv 1 (33–35), Zv 2 (31–33), Zv 3 (17–18), para-anal (32–35), post-anal (40–42); shape of setae as in adult female.

Legs. Lengths: I: (658–665); II: (525–540); III: (450–460); IV: (610–625). Numbers of setae of leg segments similar to those of adult female. Shape of setae as in adult female, except two ventral setae on femur II and one ventral seta on each of genu and tibia II, spur-like ( Fig. 11 ). All legs with pretarsi, similar to those of adult female.

Etymology. The name alagoensis is derived from Alagoas (the state where the type specimens were collected + ensis, a suffix denoting place).

Remarks. The following characteristics distinguish other Hydrogamasellus species from Hydrogamasellus alagoensis n. sp.: dorsal idiosomal setae aciculate and smooth or slightly pilose, and ventrianal shield with 6–7 pairs of setae.

Figures

FIGURES 1 – 7. Hydrogamasellus alagoensis sp. nov., female. 1. Antiaxial view of chelicera; 2. Palp genu; 3. Epistome; 4. Hypostome; 5. Dorsal shield; 6. Ventral idiosoma; 7. Tritosternum. Lyrifissures enlarged for improved visibility.

FIGURES 8 – 11. Hydrogamasellus alagoensis sp. nov., male. 8. Antiaxial view of chelicera; 9. Epistome; 10. Ventral idiosoma; 11. Anterolateral view of femur, genu and tibia of leg II. Lyrifissures enlarged for improved visibility.