Lumbricidae Rafinesque-Schmaltz, 1815

Plisko, Jadwiga D. & Nxele, Thembeka C., 2015, An annotated key separating foreign earthworm species from the indigenous South African taxa (Oligochaeta: Acanthodrilidae, Eudrilidae, Glossoscolecidae, Lumbricidae, Megascolecidae, Microchaetidae, Ocnerodrilidae and Tritogeniidae), African Invertebrates 56 (3), pp. 663-663 : 687-689

Family Lumbricidae Rafinesque-Schmaltz, 1815

Sixty-three genera with approximately 163 valid species accredited to the family Lumbricidae (Csuzdi 2012) are recorded from various terrestrial or semi-terrestrial and limnic biotopes. Of these, 33 species are cosmopolitan (Blakemore 2010), of which nineteen (species with subspecies) were recorded in RSA. The characters presented in the key are based on those observed at their collection; however, they are enriched by some other features noted in species during advanced study by Blakemore (2004 b, 2010), Csuzdi & Zicsi (2003), Jamieson (1967) and Plisko (1973), and observation based on the material gathered in the NMSAD. To better understand the terminologies in the species decriptions, it is advised to refer to the Glossary. The key presented below refers to species recorded from South Africa to date. Specimens’ external characters may indicate assignment to a species; however, dissection and internal study are advised to confirm the identifications. For further diagnostic characters and data on some other species possibly found in RSA, see Blakemore (2010), Csuzdi and Zicsi (2003), Stephenson (1930) and Michaelsen (1900).

The main characters of species known from RSA attributed to the family Lumbricidae : Body cylindrical, elongated for the entire length of the body, with some variability occurring at its posterior part, which may be flattened ( Lumbricus ) or square-shaped ( Eiseniella ). Body length from 20–150 mm, diameter 1.5– 7 mm. Segmentation simple along the whole body ( Fig. 8C ), sometimes dorsally slightly marked superficially, transversally. Setae lumbricine ( Fig. 9A–C ) (e.g. eight setae at each segment with the exception of the prostomium and anal segment; variably located at segments: setae may be closely, moderately or widely paired in four rows, or distantly separated in eight lines). Prostomium ( Fig. 7C, 7D ) epilobous or tanylobous. Dorsal pores present; location of first pore variable, distinct for species. Spermathecal pores present or absent; if present, paired, in intersegmental furrows 9/10 and 10/11 or in 9/10, 10/11, 11/12. Female pores paired (frequently inconspicuous) in 14 above setae b (exception Eiseniella where they are ventrally to setae a). Male pores paired, in segment 15 or exceptionally in 13 ( Eiseniella tetraedra ), with variably swollen glands around pores (exception Lumbricus rubellus and Lumbricus castaneus , where these appear as clear pores, with no swollen glands around). Clitellum saddle-shaped ( Fig. 5B ), appearing on some of the segments 22–36; a number of segments covered by clitellar tissues and their position is the taxonomic species character.Tubercula pubertatis present, ( Fig. 8C ) variably shaped, from band-like, ridge-like, knob-shaped to sucker-like tubercles, with location on some of the segments 24–35; it is an important, exclusive species character. Holandric condition (two pairs of testes; each with male funnels in segment 10 and 11 respectively). Spermathecae present or absent; if present: adiverticulate, paired, in segment 9 and 10 respectively, or in 9, 10, 11. Seminal vesicles paired, in four segments 9–12, or in three 9, 11, 12, or in two 11, 12. Excretory system holoic. Crop intestinal in 15–16. Gizzards intestinal in 17 or 17–18. Calciferous glands oesophageal, present; with or without lateral pouches. Intestinal caeca absent. Prostates absent.

Notes: It should be noted that Lumbricus terrestris Linneaus, 1758 does not occur in RSA as had been previously indicated ( Ljungström 1972; Plisko 2010).

Key to genera of the family Lumbricidae Rafinesque-Schmaltz, 1815 (introduced to South Africa)

1 Setae lumbricine closely paired in four regular rows ( Fig. 9A )..............................2

– Setae widely paired in four rows, or distantly placed in eight regular lines. Prostomium epilobous ( Fig. 7C ).............................................................................6

2 Male pores in segment 13 or 14 or 15. Gizzard small, in 17 .................................... ..................................................................................... Eiseniella Michaelsen, 1900 Description: Pre-clitellar body cylindrical, in post-clitellar region quadrangular, with four pairs of setae at each segment located post-clitellar at the four corners of the body. Prostomium epilobous. Male pores with variably sized glandular swellings, not extending on neighbouring segments. Spermathecal pores paired, in intersegmental furrows 9/10 and 10/11 respectively. Spermathecae paired, in 9 and 10 respectively. Seminal vesicles in four segments 9–12. Body length 15–65 mm.

Notes: Only one species known from RSA: E. tetraedra Savigny, 1826

– Male pores in segment 15. Gizzard in 17–18 .........................................................3

3 Prostomium epilobous. Male pores ventro-laterally, with variably developed glandular tumescens around the openings extended or not on the neighbouring segments..................................................................................................................4

– Prostomium tanylobous. No glandular tumescens around male pores...................... ....................................................................................... Lumbricus Linneaus, 1758 Description: Pigmented. Dark violet dorsally, light ventrally. Male pores very small, difficult to trace. Body length 30–145 mm. Spermathecal pores in intersegmental furrows 9/10 and 10/11. Spermathecae in 9 and 10. Seminal vesicles in three segments 9, 11, 12 respectively. Calciferous glands in 10–12. Excretory system holoic, nephridial bladders J-shaped.

Notes: Two species known from RSA: L. castaneus ( Savigny, 1826) and L. rubellus Hoffmeister, 1843

4 Pigmented................................................................................................................5

– Unpigmented ................................................................ Aporrectodea (Örley, 1885) Description: Red, grey or with a tint of black. Male pores with small glandular swellings slightly extending on neighbouring segments. Body length 30–150 mm. Clitellum located on some of the segments 24–35.Tubercula pubertatis as continuous bands or simple tubers separated or not by transverse furrows. Spermathecae and spermathecal pores present. Two pairs of spermathecae in segment 9 and 10 respectively, and their pores in intersegmental furrows 9/10 and 10/11. Calciferous glands in 10–12 with lateral pouches in 10. Excretory system holoic, with nephridial bladders U- or J-shaped. Seminal vesicles variable in size and number in: 11 and 12, or 9, 11 and 12, or 9, 10, 11, 12.

Notes: Four species: rosea , longa , caliginosa and trapezoides ; all described under numerous synonymic names. Occur in variable biotopes, with easy adaptation to wide-ranging environmental conditions.

5 Dorsally dark red to violet, ventrally yellowish grey with no coloured stripes. Male pores with small glandular swellings, not extending on neighbouring segments ..... ............................................................................... Allolobophoridella MršiĆ, 1990 Description: Body length 30–65 mm. Prostomium epilobous ( parva ) or occasionally tanylobous ( eiseni ). Clitellum present or absent; if present, on 23, 24, 25–32. Spermathecae, spermathecal pores and tubercula pubertatis absent.Seminal vesicles in two segments 11 and 12. Calciferous glands in 10–12, with lateral pouches. Excretory system holoic, with nephridial bladders U-shaped.

Notes: Two species known in RSA: Al. eiseni ( Levinsen, 1884) and Al. parva (Eisen, 1884) .

– Red-brown, with less pigmented intersegmental stripes, or dorsally more uniformly purple, yellow ventrally. Glandular swellings of male pores may slightly extend onto neighbouring segments .................................................... Eisenia Malm, 1877 Description: Body length 30–120 mm. Clitellum on segments 25, 26–32, 33. Tubercula pubertatis as narrow bands along ventral borders of clitellum covering three segments of 28, 29–30, 31. Septa 6/7–8/9, slightly thickened. Spermathecae and spermathecal pores paired, present in intersegmental furrows 9/10 and 10/11. Four pairs of seminal vesicles in segments 9–12. Calciferous glands in 10–12 without distinct lateral pouches. Excretory system holoic, with nephridial bladders simple, sausage-shaped.

Notes: Two species, E. fetida and E. andrei , are anatomically alike but differ at a molecular level.

6 Setae paired, and widely spaced with variable distances between paired setae......7

– Setae spaced widely in eight regular lines along the body length, or occasionally the distance between setae varies .................................. Dendrobaena Eisen, 1873 Description: Violet to light red dorsally, light ventrally, sometimes iridescent. Dorsal pores present or absent. Spermathecal pores present or absent; if present, in intersegmental furrows 9/10 and 10/11, or in 9/10, 10/11, 11/12. Clitellum on some of the segments 27–33. Tubercula pubertatis present or absent. Spermathecae present or absent; if present, in two segments 11 and 12, or in three, 9, 10, 11. Calciferous glands in 11–13, with lateral pouches in 11, 12; or in 11, 12 with lateral pouches in both; or in 10, 11, 12 with no pouches. Excretory system holoic, with sausage-shaped nephridial bladders.

Notes: Four species: D. cognettii (Michaelsen, 1903) , D. hortensis ( Michaelsen, 1890) , D. octaedra ( Savigny, 1826) , and D. veneta veneta ( Rosa, 1886) .

7 Pigmented. Dorsally dark red to violet, pale ventrally.............................................. .................................................................................... Dendrodrilus Omodeo, 1956 Description: Setae paired widely ( Fig. 9B ), with constant ratio. Body length 26–65 mm. Prostomium epilobous. Clitellum covers five to six segments, on some of 25, 26, 27–31, 32, not extending on 33. Tubercula pubertatis present or absent; if present, on 28–30 or 29–30 as broad rectangular bands, or reduced to slender strips. Spermathecal pores in 9/10 and 10/11, or absent. Seminal vesicles in three segments (9, 11, 12) or in two (11 and 12). Calciferous glands in 10–12, with lateral pouches in 10. Excretory system holoic, with nephridial bladders U-shaped.

Notes: One species Dn. rubidus ( Savigny, 1826) with two subspecies: Dn. rubidus rubidus ( Savigny, 1826) and Dn. rubidus subrubicundus ( Eisen, 1873) .

– Unpigmented. Colour whitish grey, sometimes slightly dark ................................. ............................................................................................ Octolasion Örley, 1885 Description: Setae on first few segments paired moderately, then widely along the whole body. Body length 30–145 mm. Prostomium epilobous. Male pores with prominent glandular tumescens, often extending on neighbouring segments. First dorsal pores around intersegmental furrow 10/11. Clitellum initiates at segment 29 or 30, terminating at 34 or 35. Tubercula pubertatis as thin bands on 30–34, 35. Spermathecal pores paired, in 9/10 and 10/11. Seminal vesicles paired, in 9–12. Calciferous glands in 10–11 with lateral pouches in 10. Excretory system holoic, with nephridial bladders ‘ocarina’ shaped. Notes: Two species: O. cyaneum ( Savigny, 1826) and O. lacteum ( Örley, 1881) , morphologically similar, although differing in the species’ constant position of the clitellum and tubercula pubertatis.

Figures

Fig.8.Segmentation:(A)Secondary annulation:an anterior part ofMicrochaetus papillatus (Microchaetidae) showing intersegmentalfurrows separating segments, marked bynephridial pores ofholoic nephridia; (B–C) simple: (B) Eudrilus eugeniae (Eudrilidae); (C) Aporrectodea trapezoides (Lumbricidae) showing tubercula pubertatis and male pore with tumescens.

Fig. 9. Setal arrangements: (A –C) lumbricine arrangement: (A) closely paired; (B) widely paired; (C) separated in eight rows; (D) perichaetine arrangement.

Fig. 7. Prostomium: (A) zygolobous; (B) prolobous; (C) epilobous; (D) tanylobous.

Fig. 5. Clitellum: (A) annular (schematic); (B) saddle-shaped (schematic).