Nothogynus Walter et Krantz, 1999

Karg, W. & Schorlemmer, A., 2011, New Insights Into The Systematics Of Parasitiformes (Acarina) With New Species From South America, Acarologia 51 (1), pp. 3-29 : 18-19

– Nothogynus Walter et Krantz, 1999

• Microgyniidae Trägårdh, 1942 Two genera:

– Microsejus Trägårdh, 1942

– Microgynium Trägårdh, 1942

Systematics — A pedunculate phoretic deutonymph occurs during the developmental cycle of the species of these groups. Adults have marginal shields or marginal grooves, in parts mesonotal and pygidial shields on the dorsum. These special characteristics are developed also in the large group of Uropodina Kramer. Krantz & Walter (2009) also recognized these connections.

From investigations of the chaetotaxy in the larval stage of Microgyniina , further important characteristics are detected: On the posterior part of the dorsum a row of setae ancestrally localized in the middle is displaced to the margin ( Figure 8a ). This synapomorphy is characteristic for the Uropodina and also for the Ixodides ( Figures 8b and c ). These groups have been classified as Margotrichina by Karg & Schorlemmer (2008). The Uropodina show that throughout evolution a small shield must have originally developed in the middle of the posterior part of dorsum shifting setae simultaneously to the margin ( Figure 8b ).

In the Ixodides, adaptation to blood sucking and stretching the body led secondarily to an elimination of the shield. In the Microgyniina , sclerotisation of the larva is so weak that the ancestral shield is also not detectable. The abnormal position of setae, however, is preserved.

In the other two large groups of Parasitiformes – the Antennophorina and the Gamasina – the larval setation has been preserved consistently as in the ancestral figuration ( Figure 9 ).

Based on these new insights, we integrate the Microgyniina into the Margotrichina. A cladogram is drawn based on synapomorphies ( Figure 10 ).

Figures

FIGURE 8: Dorsum of larval stages in different groups of Margotrichina showing the shifting of setae I3, ancestrally caused by development of a special pygidial shield within the posterior rows of setae; a – Microgyniina, 220 µm; b – Uropodina, 250 – 380 µm; c – Ixodides, 500-600 µm long (after Hirschmann 1961 and Karg & Schorlemmer 2008).

FIGURE 9: Dorsum of larval stages in groups of Parasitiformes showing undisturbed transverse rows of setae which we interpret in accordance with Christian & Karg (2008) as residues of an ancestral body segmentation; a – Gamasina – Ascides, 270 – 290 µm; b – Gamasina – Eugamasides, 130 – 455 µm; c – Antennophorina – Sejides, 290 – 370 µm long. Some groups have developed special shaped setae, which we have to regard as secondary developments (some modified after Karg 1962, 1965 and Hirschmann 1957).

FIGURE 10: Cladogram of the subgroups of the Margotrichina Karg et Schorlemmer, Synapomorphies 1 – 3, characteristics for the subgroups of the Margotrichina; our present results confirm previous findings: