DAVACARIDAE Kethley, 1977
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publication ID |
https://doi.org/ 10.1080/00222930310001617733 |
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persistent identifier |
https://treatment.plazi.org/id/243AE64B-FC6B-FFAF-0094-F7BC556C70EE |
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treatment provided by |
Carolina |
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scientific name |
DAVACARIDAE Kethley, 1977 |
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Family DAVACARIDAE Kethley, 1977 View in CoL View at ENA
Type genus. Davacarus Hunter, 1970 .
Diagnosis. Trigynaspine Mesostigmata with setae av4, pv4 present on intercalary sclerite on tarsus IV; trochanter I with six setae; palp genu with six setae; chelicerae chelate-serrate, pilus dentilis absent, movable digits ( figures 1A, B View FIG , 4C View FIG , 8C View FIG , 9C View FIG ) with strongly fimbriate ventral excrescence, serrate paraxial membrane, and finger-like process arising antiaxially; tritosternal laciniae fused basally; tectum denticulate, without median keel; adults with two to four pairs of large opisthosomal gland openings ( figures 2C, D View FIG , 4A View FIG , 7A View FIG , 9A View FIG ). Dorsum of deutonymphs ( figure 6D View FIG ) and adults ( figures 2C View FIG , 4A View FIG , 7A View FIG , 9A View FIG ) with four major shields, each usually surrounded by leathery cuticle in fully sclerotized adults ( figure 2C View FIG ). Postanal seta present in larva and nymphs, absent in adults. Claws on legs I large, sessile. Chaetotaxy of legs I-II-III-IV: coxae: 2-2-2-1; trochanters: 6-5-5-[5, 6]; femora: 12-10-7-8; genua: 11-11-11-10; tibiae: 13-10-10-10, respectively. Palpal chaetotaxy: trochanter, femur, genu, tibia: 2-5-6-14, respectively; palp apotele with three tines. Females with six pairs of intercoxal setae, welldeveloped mesogynial shield, and usually with endogynial complex. Males with five to six pairs of intercoxal setae (z/2 genital valve seta), subcircular and
crescent-shaped genital valves between coxae III–IV; chelicerae not obviously modified for sperm transfer; gnathotectum sometimes sexually dimorphic ( figure 8B View FIG versus 8E).
Remarks. As noted by Hunter (1970), species of Davacarus appear to have only two dorsal shields because of a pigmented leathery sclerotization of the cuticle around the primary shields. In teneral adults, the true limits of the dorsal shields are readily apparent, but as the new adult hardens the shields appear to grow and coalesce as a dark, thickened, micropunctate band forms around each shield. The same process occurs ventrally and results in a wellprotected mite. This is especially true in the new genus described below, where the leathery secondary sclerotization results in the appearance of a holodorsal shield ( figure 2C View FIG ).
The results of a cladistic analysis supported the monophyly of Davacaridae and its division into two clades, represented by a new species and genus described below, and three species in the type genus that share the loss of the anterior genital shield (pregenital shield) and its apparent conversion into a complex endogynium with a pair of punctate processes ( figure 3 View FIG ). The presence of four primary dorsal shields is a juvenile character and the retention of these shields in the adult represents a synapomorphy of the family that separates Davacaridae from all other Trigynaspida. Other distinctive synapomorphies of the family are a thick, finger-like paraxial process that moulds to the cheliceral teeth ( figures 1A, B View FIG , 4C View FIG , 8C View FIG , 9C View FIG ), the form of the single ventral cheliceral excrescence, and the enlarged opisthosomal gland openings ( figures 2C, D View FIG , 4A View FIG , 7A View FIG , 9A View FIG ). Two genera and four species are known, including the new genus and three new species described below.
Key to adults of Davacaridae
1 Genital opening of female covered by three shields ( figures 2B View FIG , 8A View FIG , 10A View FIG ), pregenital
shield absent; seta st4 laterad other sternal setae; endogynium ( figure 3 View FIG ) with punctate regions; dorsal setae acuminate, simple to barbed ( figures 7A View FIG , 9A View FIG ); four pairs of enlarged opisthosomal glands, posterior glands sessile.. Davacarus Hunter (2)
– Genital opening of female with four shields ( figures 2A View FIG , 5A View FIG ), including pregenital shield with punctae and a pair of setae (st4); complex endogynium absent; dorsal setae short and densely pilose ( figure 4A View FIG ); two pairs of large lateral opisthosomal glands on short horn-like processes ( figures 2C, D View FIG , 4A View FIG )...................... Acanthodavacarus n. g. klompeni n. sp.
2 Setae on dorsal shields relatively long ( figures 7A View FIG , 9A View FIG ), most extending well beyond
insertion of next seta in series; opening of anteriormost opisthosomal gland in soft cuticle; fixed digit with § 12 teeth; male genital valves with a pair of setae 3
– Setae on dorsal shields relatively short, most just reaching insertion of next seta in series; anterior opisthosomal gland on small platelet with a pair of pores; fixed digit with ƒ 10 teeth; male genital valves nude... Davacarus gressetti Hunter
3 Podonotal shield reticulate throughout ( figure 7A View FIG ); mesonotal shields each with
seven setae; pygidial shield with eight setae; fleshy, fimbriated process present behind coxa IV ( figure 7B View FIG ); sternal setae st1 and st4 of female in soft cuticle ( figure 8A View FIG ); movable digit with six to eight teeth ( figure 8C, F View FIG ); internal malae
barbed ( figure 8D View FIG )............ Davacarus reginaldi n. sp.
– Podonotal shield reticulate laterally, smoothly micropunctate medially ( figure 9A View FIG ); mesonotal shields each with six setae; pygidial shield with seven setae; no fleshy fimbriated process at coxa IV; sternal seta st1 on small platelet, st4 on sternal shield with st2–3 ( figure 10A View FIG ); movable digit with 15–16 teeth ( figure 9C View FIG ); internal malae simple ( figure 9D View FIG ).......... Davacarus lindquisti n. sp.
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.