Natrix

Cadle, John E., 2011, Hemipenial morphology in the North American snake genus Phyllorhynchus (Serpentes: Colubridae), with a review of and comparisons with natricid hemipenes, Zootaxa 3092 (1), pp. 1-25 : 10

Natrix

Natrix maura (Linnaeus) (CAS 138733; Fig. 5C ). Hemipenis bilobed, the left lobe much shorter than the right. Sulcus spermaticus simple and sinistral, deviating slightly proximal to the crotch. However, the sulcus appears sinistral mainly as a result of shortening and reduction of the left lobe, rather than a distinct leftward deviation of the sulcus itself. On the apex the sulcus abruptly opens into a broad deep groove that traverses the crotch and medial lobe surfaces from the tip of one lobe to the tip of the other (no distinct sulcus groove within the nude area). The groove on the left lobe is narrower and shorter than the groove on the right lobe. This groove is bordered on all sides (sulcate and asulcate) by a distinct fleshy and somewhat spiny border (border thickened but containing bases of some spines).

Natrix tessellata (Laurenti) (CAS 183115; Figs. 4C and 5D ). Hemipenis slightly bilobed, the left lobe slightly shorter than the right. Sulcus spermaticus simple and centrolineal to the crotch, where it remains distinct within the nude area and the tip deviates slightly toward the base of the left lobe (sinistral); tip of the sulcus is very slightly expanded into a small oblong basin, ending within the nude apex. Entire crotch of the organ (including all medial surfaces of the lobes) is nude but without a distinct bounding ridge (as in N. maura ).

Figures

FIGURE 4. Everted hemipenes of natricids in sulcate view. A, Afronatrix anoscopus (CAS 230205). B, Amphiesma bitaeniatum (CAS 215037) (detail of apex shown in Fig. 5A). C, Natrix tessellata (CAS 183115) (detail of apex shown in Fig. 5D).

FIGURE 5. Details of apical morphology of natricid hemipenes. A, Amphiesma bitaeniatum (CAS 215037). B, Amphiesma stolatum (CAS 215361). C, Natrix maura (CAS 138733). D, Natrix tessellata (CAS 183115). Arrow in B indicates the asulcate ridge delimiting the apical nude area (see text).