Tydeus croceus, C. L. KOCH, 1836

André, Henri M., 2005, In search of the true Tydeus (Acari, Tydeidae), Journal of Natural History 39 (13), pp. 975-1001 : 988-990

publication ID	https://doi.org/ 10.1080/00222930400002838
persistent identifier	https://treatment.plazi.org/id/03EB879B-FFBE-FFF1-FEA6-6B438668FB83
treatment provided by	Felipe
scientific name	Tydeus croceus
status

Treatment

Tydeus croceus (L.) sensu Oudemans (1928b)

( Figures 2A View Figure 2 , 3A View Figure 3 , 4A View Figure 4 , 5A View Figure 5 , 6A View Figure 6 , 7 View Figure 7 , 8 View Figure 8 )

The oldest illustration of the species was given by Oudemans (1914, p 122, Figures 7–10 View Figure 7 View Figure 8 View Figure 9 View Figure 10 in Plate XII). However, as already mentioned by Thor (1933, p 17), Oudemans’ (1914) species was not the real croceus . Indeed, the species illustrated in his Plate XII (surprisingly entitled ‘‘ T. foliorum ’’) exhibits distinctive spatulate setae at the posterior tip of the abdomen.

As already commented upon, the identity of the species was established by Oudemans (1928b, p 377) who collected the mite from the same tree genus ( Salix ) as Linnaeus. The description was, however, issued later by Thor (1932) who reproduced Oudemans’ original drawings (his Figures 1 View Figure 1 –20). The first 11 figures were again published by Thor (1933, p 17 Figures 18–28). The description is nevertheless imprecise on several points, e.g. the leg chaetotaxy. Consequently, the species was listed as an ‘‘ancient species’’ not identifiable by Kaźmierski (1998). Therefore, a detailed description is given, illustrated by Figures 7 View Figure 7 , 8 View Figure 8 .

Prodorsum

Prodorsum recurved with two eyespots ( Figure 8A View Figure 8 ).

Leg chaetotaxy in adults

I(8-4-3-3-1), II(6-2-2-3-0), III(5-2-1-1-1), and IV(5-2-1-1-0). Oudemans’ figures ( Figures 1 View Figure 1 , 2 View Figure 2 in Thor 1932; Figures 18, 19 in Thor 1933) contain thus three errors: the famulus is not drawn, the trochanteral III is omitted, and tarsi III and IV bear only four setae. Eupathidia on tarsus I: ft 99, (tc) and (p). Solenidiotaxy: 2. The leg phanerotaxy (eupathidia included) does not vary from the deutonymph to the adult.

Palp chaetotaxy

Ad-DN(6-2-2) plus a tarsal solenidion and with a double terminal eupathidium on the distal segment ( Figure 8E View Figure 8 ). Stylet-like movable digit ( Figure 8F View Figure 8 ).

Epimeral formula

Ad-DN(3-1-4-2). Vertition and bisynthesis has been observed on podosoma IV. Coxal organ simple and oval ( Figure 6A View Figure 6 ).

Genital chaetotaxy

Ad(0,4-6-4), TN(4-4) and DN(1-2). In some adults, there are only five pairs of genitals (as in Oudemans’ drawings) but the presence of a single pair of genitals has been observed in all deutonymphs. Extended striation pattern ( Figure 8C View Figure 8 ).

Specimens from willow and rye are similar in morphology and size. Dorsal setae (except the trichobothridia) are not smooth as in Oudemans’ drawings, but serrate ( Figure 8B View Figure 8 ). Long posterior setae are particularly fragile and, once broken, may give the impression that they are truncate.

Legs ornamented with ventral semi-annular thickenings similar to those described in some Ereynetidae ( Figure 8D View Figure 8 ). Such ornamentation was not drawn by Oudemans and has not been reported in other tydeid species. Dorsal setae on genua tapered ( Figure 8G View Figure 8 ).

Length of the idiosoma (in Mm)

Specimens from willow: undetermined adult: 416; ♀: 346; DN: 269¡12 (n 55). Specimens from rye, „: 380¡36 (n 52); ♀: 335¡2 (n 52); TN: 286; DN: 263¡12 (n 56). Usually, males are smaller than females. NS(vi)525–27, NS(ep)532.