Alboglossiphonia afroalpina Jueg, 2023

Jueg, Uwe, 2023, Alboglossiphonia afroalpina sp. nov. and Alboglossiphonia buniana sp. nov. - two new leech species from Africa and revision of the genus Alboglossiphonia Lukin, 1976 in Africa, Evolutionary Systematics 7 (1), pp. 1-34 : 1

Alboglossiphonia afroalpina Jueg sp. nov.

Material.

In addition to the holotype from Mt. Kenya, there were 20 specimens from the Mt. Elgon massif in Kenya, on the border with Uganda, which were collected in 1953 ( Sciacchitano 1960). They turned out to belong to the species described here. In Sciacchitano (1960) these animals were named Glossiphonia disjuncta .

Holotype: 1 specimen collected on February 20th of 2010 from Kenya, Mt. Kenya national park Nanyuki Tarn , 4,493 m above sea level, leg. Dr. Ulrich Bößneck; body length 6.0 mm, maximum width 1.6 mm; deposited at the Zoological Museum of Hamburg ( Germany), Coll. - No.: ZMH P-30427 (specimen 1 in Table 1 ).

Additional material.

1 specimen collected December of 1953 from Kenya, Mt.-Elgon-Massif near Kitale , 3,850 m above sea level; leg. Dr. J. Bouillon ( Sciacchitano 1960 as Glossiphonia disjuncta ); deposited at the Royal Museum of Central Africa in Tervuren ( Belgium), Coll. - No.: 29878 (specimen 2 in Table 1 ) .

19 specimens collected December 11th, 1953 from Kenya, Mt.-Elgon-Massif near Kitale , east-northeast from the previous location, 3,000 m above sea level; leg. Dr. J. Bouillon ( Sciacchitano 1960 as Glossiphonia disjuncta ); deposited at the Royal Museum of Central Africa in Tervuren ( Belgium), Coll. - No.: 29868-29877 (specimens 3-21 in Table 1 ) .

Type locality.

Kenya, Central Kenya Province, Naro Moru, Mt. Kenya National Park north of the Teleki Valley, Nanyuki Tarn (mountain lake) (Fig. 1 ), 0.15493°S, 37.29793°E, 4,493 m above sea level, February 20th, 2010, leg. Dr. Ulrich Bößneck.

Diagnosis.

Alboglossiphonia species up to 10.5 mm long and up to 2.2 mm wide; very elongated shape for the genus; almost circular suckers with thick walls, caudal sucker small (about 1/3 of the maximum body width); ground color unknown, numerous small roundish to oblong spots dorsally and less numerous ventrally (only species of the genus with this character); smooth surface, no prominent tubercles or papillae; eye position typical of the species, but with high variability; separation of the small and poorly visible gonopores by two annuli; internal anatomy unknown.

Description.

The external morphology (number and position of eyes, annulation, colouration, papillation, suckers and the position of genital pores, size) was examined for the holotype and another 20 specimens. The internal morphology was not investigated (see above).

Body form and size. The body is oblong with a length of 10.5 mm. The maximum width in the second half of the body is 2.2 mm. The body is approx. 0.6 mm wide both at the beginning of the head area and at the base of the rear suction cup. Dorsum is slightly curved, ventral flat. The approx. 0.5 mm long head area is set off by a neck furrow. The hind edge of the animal is strongly concave dorsally, so that part of the posterior sucker is exposed. In egg-carrying specimens, a ventral bell-like bulge was observed to protect the clutch, as is typical for this genus.

Annulation. 69 annuli were counted. The first six annuli are in the head area. All annuli have the same width.

Suckers and mouth. The cranial sucker is rounded to slightly crosswise: 0.48 mm in length and 0.53 mm in width (max. 0.62 mm and 0.65 mm). The edge is thickened on all sides and resembles a tire. There is a relatively large mouth opening in the center of the deep, bowl-shaped cranial sucker (Fig. 7 ). It is triangular, with the lower edge being slightly convex and the other two sides being slightly concave. The caudal sucker is almost circular with 0.56 mm length and 0.61 mm width (max. 0.75 and 0.85 mm). The width of the caudal sucker is on average about one third of the maximum body width. The caudal sucker is only very deep in the middle, the edges are reinforced like a ring like the cranial sucker.

Colour and pattern. In life, the basic color is probably light brown to beige, and clearly lighter on the ventral side. The spotting on the dorsal side is very characteristic, consisting of elongated to rounded spots that are only slightly darker than the basic color (Fig. 8 ). The animals from the Elgon Mountains have more rounded spots. There are 8-12 (up to 15) such spots on each annulus. The patches often touch the annulus in front of it, but rarely extend beyond it. Altogether they give a diffuse pattern on the whole dorsal side, beginning behind the eyes up to the posterior sucker. The head area and suction cups are free of pigment. The spots are weaker on the anterior half of the body than on the posterior half. Sometimes interrupted longitudinal rows or rows of different lengths are indicated, which have a higher concentration of spots on the sides of the body. There are also spots ventrally, but fewer and weaker, which are connected to indistinct lines at the edges.

Papillae and tubercles. The entire body is smooth. There are no tubercles or prominent papillae. Only tiny, evenly spaced, sensory papillae are visible at high magnification. These are present on each annulus as a transverse row.

Eyes. The eyes are typically formed for the genus Alboglossiphonia , with a high degree of variability in arrangement and partial reduction of the eyes (Fig. 9 ). However, this is not unusual for the genus ( Oosthuizen 1978a, b; Jueg 2008). The first pair of eyes is at the anterior edge of the 4th annulus, the second at the posterior of the same. The third pair of eyes is on the 5th annulus. The 2nd and 3rd pair of eyes are about the same size, and the left and right eyes of each pair are very close together, and sometimes longitudinally fused. The first pair of eyes, which is significantly smaller, is much closer together. The third pair of eyes are slightly further apart than the second. Shifts in position can affect all eyes, with a strikingly high level of variability.

Gonopores. Both gonopores are very small and inconspicuous. They each lie in a furrow and are separated by two annuli. The furrows appear somewhat darker in the area of the gonopores and have the shape of a black slit (Fig. 10 ). The gonopores can already be seen in small animals from about 5 mm in length.

Etymology.

The newly described species is named after its occurrence in the Afroalpine zone of the East African mountain massifs Mt. Kenya and Mt. Elgon.

Differential diagnosis.

The affiliation to the genus Alboglossiphonia results from the position of the eyes and the distance between the gonopores. Eleven species are known from Africa, only six of these from south of the Sahara (including this and Alboglossiphonia buniana sp. nov.). Internal features (e.g. the number and shape of the crop caeca) cannot be used for differentiation, but some very constant features such as the spacing of the gonopores, the shape and size of the suckers, the structure of the surface or the formation of spots and patterns distinguish among these species.

The gonopores of the species Alboglossiphonia afroalpina sp. nov. have a spacing of 2 annuli, differing from A. conjugata (Oosthuizen, 1978) and A. disuqi El-Shimy, 1990, where the spacing is only 1 annulus, and from A. hyalina , which has only one common gonopore. Alboglossiphonia conjugata and A. disuqi also have papillae and warts as well as rows of spots. The location of the gonopores of Alboglossiphonia afroalpina is identical with following species: A. disjuncta (Moore, 1939), A. iberica Jueg, 2008, A. levis Gouda, 2010, A. macrorhyncha (Oosthuizen, 1978), A. namaquaensis (Augener, 1936) and A. polypompholyx Oosthuizen, Hussein & El-Shimy, 1988. The presence of warts and prominent papillae clearly distinguish Alboglossiphonia disjuncta , A. macrorhyncha and A. polypompholyx from A. afroalpina sp. nov. Alboglossiphonia afroalpina does not have a transparent margin like that of A. iberica and A. namaquaensis . Alboglossiphonia afroalpina sp. nov. can be separated from all other species of the genus by its clearly elongated shape, which can only rarely be described as slightly oval, and by the distinctive spotting. Only Alboglossiphonia polypompholyx has a comparable body shape, but it is clearly covered with warts. The color pattern is unique for the genus worldwide.

The geographic and habitat distribution distinguish Alboglossiphonia afroalpina as a new species. The occurrence in water bodies in the alpine zone of the East African mountain massifs is unique to A. afroalpina .

Ecology.

The mountain lake Nanyuki Tarn on Mt. Kenya (Fig. 1 ) has flat, stony shores, with localized boggy areas. From a depth of about 0.3 m, the sediment becomes muddy. Nevertheless, the Nanyuki Tarn has high visibility. Submerged vegetation is only sparsely developed. The accompanying fauna is just as species-poor, with only Chironomidae and Pisidium montigenum Kuiper, 1966 found, the latter frequently. In all of Dr. Ulrich Bößneck’s collecting effort, no gastropods were found in mountain lakes above 3,000 m in the Mt. Kenya massif. Alboglossiphonia afroalpina sp. nov. therefore obviously feeds on insect larvae and small mussels of the genus Pisidium .

Nothing is known about the ecology of the specimens found in 1953 in the Mt Elgon massif, except for the sea level at which the waters (probably mountain lakes) were located. Three of the animals carried eggs, so December can be named as the period for reproduction and brood care.

Distribution.

So far, the species is only known from the mountain massifs of Mt. Kenya and Mt. Elgon in Kenya. It is very likely that A. afroalpina sp. nov. is widespread in these massifs, and it could also be distributed on other high mountains in East Africa. A targeted search in mountain lakes in the East African high mountains would be desirable to expand the description provided here. Whether A. afroalpina also occurs in the lowland areas between these mountain massifs is questionable.

Figures

Figure 1. Type locality of Alboglossiphonia afroalpina sp. nov., Photo: Dr. U. Boessneck (†).

Figure 7. Alboglossiphonia afroalpina sp. nov., cranial sucker with mouth pore, Holotype.

Figure 8. Alboglossiphonia afroalpina sp. nov., dorsal, Holotype.

Figure 9. Eye positions of Alboglossiphonia afroalpina sp. nov., individual numbers correspond to Table 1.

Figure 10. Alboglossiphonia afroalpina sp. nov., Gonopores, Holotype, Photo: P. Michalik.