Dichogaster (Diplothecodrilus) pinguis Cognetti, 1910

Csuzdi, Csaba, 2005, Earthworms (Annelida: Oligochaeta) of Sao Tomé, Journal of Natural History 39 (33), pp. 3039-3058 : 3045-3046

Dichogaster (Diplothecodrilus) pinguis Cognetti, 1910

( Figure 8 )

Dichogaster pinguis Cognetti 1910, p 86 .

Benhamia pinguis: Csuzdi and Zicsi 1994, p 218 .

Benhamia pinguis: Csuzdi 1995, p 107 .

Material examined

AF/5046 one ex. Sao Tome´, on the volcano around Lago Amélia, 1450 m asl, leg. Cs. Csuzdi, 30 August 2000. AF/5067 one ex. Sao Tome´, OBO National Park, leg. J. Measey, January 2002.

Remarks

This species was transferred to Benhamia Michaelsen, 1889 based on the investigation of the softened and somewhat macerated type specimen ( Csuzdi and Zicsi 1994). In the present collection we found two preadult exemplars of this species. A thorough examination of the excretory system revealed that this species belongs to the genus Dichogaster , and shows high affinity with D. (Dt.) feai but there are important differences; the greater body size, the presence of extremely thickened dissepiments in 11/12, 12/13, and 13/14 and the more numerous meronephridia (9–10 on each side). There are differences also in the penial setae. In case of D. (Dt.) pinguis they are smooth, without any remarkable sculpture, 2.2–2.4 mm long and in the middle 0.007 mm wide ( Figure 8 ). In D. (Dt.) feai the penial setae are somewhat smaller, 1.8–2 mm long and 0.003 mm wide, and furnished with several minute spines ( Figure 7 ).

While D. (Dt.) feai has been collected from rotting logs and alive possesses a greenish brown colour, D. (Dt.) pinguis was caught by digging and it is bright blue alive (J. Measey, personal observation).

Figures

Figure 7. D. (Dt.) feai: (a) tip of the seta; (b) middle part of the seta with the characteristic ornamentation.

Figure 8. D. (Dt.) pinguis, penial seta: (a) tip of the seta: (b) middle part of the seta.