Rickia odontopygiidarum Santam., Enghoff, & Reboleira, 2016

Santamaria, Sergi, Enghoff, Henrik & Reboleira, Ana Sofia P. S., 2016, Hidden biodiversity revealed by collections-based research-Laboulbeniales in millipedes: genus Rickia, Phytotaxa 243 (2), pp. 101-127 : 114-116

Rickia odontopygiidarum Santam., Enghoff, & Reboleira , sp. nov. ( Figs 36–41 )

Mycobank MB 815407

Diagnosis:—Receptacle triseriate, a: (1–)2, m: (1–)3, p: 1–2 (+ 5–7 of lateral branch). Posterior series extending in a free, lateral branch of (5–)6(–7) cells. Similar to R. gigas but smaller and with fewer cells on the receptacle.

Type: — TANZANIA. Tanga Region, Muheza District nilo F. R., 04°55’46’’S 38°39’06’’E, on Odontopoygidae indet. ( Spirostreptida ), 26 July 2000, C-F-92261, C-F!, holotype designated here ; BCB-SS · E577 bc, BCB!, isotypes designated here .

Etymology:— odontopygiidarum , referring to the host.

Thallus hyaline except for the dark brown foot, the trichogyne scar, the septa separating the appendiculate cells from appendages and antheridia, and the antheridial efferent necks. Total length 248–553 μm. Receptacle triseriate. Basal cell cylindrical, straight, with parallel sides in fully mature thalli ( Fig. 38 , I) or slightly broadened distally when immature ( Fig. 39 ), variably elongated, up to 5 times as long as broad, reaching up to 210 μm of total length in longer thalli; bordering distally on the two lower cells of the marginal series, or less usually only on the lower cell of the posterior series.

Anterior series consisting of (1–)2 superposed, variably shaped cells ( Figs 36, 38 ).

Median series located above cells a 2 and p 2; consisting of (1–)3 cells, or even absent ( Fig. 38 ).

Posterior series consisting of a basal part with 1–2 cells similar to those of the anterior series, extending in a free lateral branch 87–144 μm long, which consists of (5–)6(–7) superposed, variably flattened (2–3 times as broad as long) cells. This branch is broadened distally, each cell with appendiculate cells which randomly support appendages or antheridia above constricted and dark brown septa ( Figs 36, 38 ).

Antheridia 12–18 × 4–8 μm, above a trapezoidal to squarish stalk cell, with curved, more or less brownish, efferent necks. Paired ( Fig. 37 ) or rarely single, numerous and overlapping on the outer sides of cells of series a and p; but also on the front and rear sides of the lateral branch, where appendiculate cells are horizontally seriate, being crowded towards the distal part of the free branch ( Fig. 39 ).

Secondary appendages 23–48 μm, short, broadened and rounded distally, when deteriorating getting disorganized and their contents may extrude through the broken apex; hyaline except for the brown base and the constricted septum above the appendiculate cells. Following the same pattern of distribution on the thallus as the antheridia, they are abundant on the free branch of the posterior series, rare on the second cell of this series ( Fig. 39 ).

Perithecium 109–193 × 36–62 μm, solitary, formed from the anterior series as usual. Ovoid, its maximum breadth near the third basal part, gradually tapering towards an abruptly distinguished neck and, when seen in front view, a symmetrical tip with two outer lobes and two inner rather conspicuous lips ( Fig. 40 ), often showing corrugated edges ( Fig. 41 ). Perithecial basal cells highly flattened and inconspicuous. Perithecial stalk cell ( VI) 47–156 μm long, 2–3, or more times as long as broad, straight, with parallel sides ( Fig. 38 , VI).

Position on host:— Thalli have been found on the anterior part of the host body, on legs and ventral side of body rings.

Notes on hosts:— The family Odontopygidae is endemic in the Afrotropical region and contains numerous still undescribed genera and species.

Discussion:— This species is evidently related to R. gigas , but differs in its smaller size, the reduced number of cells in all the series, the arrangement of antheridia and appendages (overlapped and not superposed vertically as in R. gigas ), the more cylindrical and unflattened lateral branch of posterior series, the cells of receptacle showing only one pore, not several as in R. gigas , the perithecial apical lobes that lack the small papillae which are present in R. gigas , and other minor characteristics.

Rickia pachyiuli M. Bechet & I. Bechet ( Figs 56–57 )

This species was described on Pachyiulus hungaricus (Karsch 1881) ( Julida , Julidae ) from Romania (M.Bechet & I. Bechet 1986). It was compared by the authors with R. uncigeri , from which it is separated, according to them, by the greater number of receptacular cells in each series. We confirm that this is the most evident difference: R. pachyiuli has 8–9 cells in the anterior series, 11–12 in the median, and 14–15 in the posterior one, whereas R. uncigeri has 3 cells in the anterior series, 5–6 cells in the median, and 5–6 in the posterior one.

As a curiosity it is worth mentioning that some of the material we had the opportunity to study was collected about 100 years ago and conserved in 70% ethanol in Vienna (Naturhistorisches Museum Wien, NMW), and have remained up to the present day with no decay in their characteristics and appearance. These are the oldest host specimens from which the first author has had the opportunity to prepare and study useful slides, after more than 30 years of studying laboulbeniales.

Pachyiulus hungaricus is a large julid and is widespread in SE Europe.

Position on host:—The fungus is mostly in the first pairs of legs of the hosts, in highly infected specimens some thalli spread through the dorsal part of the first body rings.

Collections examined:— BOSNIA-HERZEGOVINA. Drinrsprung am Zleb, on Pachyiulus hungaricus , August 1916, Penther leg., BCB-SS·E582ac (BCB!), host in NMW (see above). SERBIA. Belgrade, Alava mountains, living specimens, D. Antic leg.

Figures

FIGURES 36–41. Rickia odontopygiidarum. Figs 36, 38. Mature thalli. Fig. 37. Detail of a set of paired antheridia. Fig. 39. Immature thallus. Figs 40–41. Perithecial apex at two different focusing levels, at right the corrugation of the inner lips is shown.(Figs 36–38, 40–41, C-F-92261; Fig. 39, SS·E577c.). FIGURES 42–46. Rickia platessa. Figs 42, 44, 46. Mature thalli. The arrow in Fig. 42 points to the dome-shaped basal cell of the primary appendage. Fig. 43. Detail of antheridia. Fig. 45. Detail of appendiculate cells on three receptacular cells. (Fig. 42, SS·E580a; Fig. 43, SS·E590c; Figs 44–45, C-F-92262; Fig. 46, SS·E590b.) (For interpretation of abbreviations see under materials and methods.) Scale bars Figs 36, 38–39, 42, 44, 46 = 50 μm; for Figs 37, 40–41 = 10 μm; for Figs 43, 45 = 20 μm.

FIGURES 52–59. Species of Rickia not described in this paper. Figs 52–53. Mature thalli of Rickia dendroiuli. Arrow in Fig. 53 points to the uppermost cell of posterior series, where a diagnostic character is shown (see text). Figs 54–55.Mature thalli of Rickia laboulbenioides. Figs 56–57. Mature thalli of Rickia pachyiuli. Fig. 58. Mature thallus of Rickia siddhartha. Fig. 59. Mature thallus of Rickia uncigeri. (Figs 52–53, WR586; Fig. 54, SS2686d; Fig. 55, SS2686e; Fig. 56, SS·E582b; Fig. 57, SS·E582c; Fig. 58, SS·E601b; Fig. 59, SS·E596c.) (For interpretation of abbreviations see under materials and methods.) Scale bars = 50 μm.