Monstrilla minuta, Isaac, 1974

Grygier, Mark J. & Suárez-Morales, Eduardo, 2018, Recognition and partial solution of nomenclatural issues involving copepods of the family Monstrillidae (Crustacea: Copepoda: Monstrilloida), Zootaxa 4486 (4), pp. 497-509 : 499

Monstrilla minuta and other species proposed by Isaac (1974a)

Suárez-Morales et al. (2013) and Suárez-Morales & McKinnon (2014) attributed Monstrilla minuta to “Isaac, 1975” without comment, but as Grygier (1995a) has noted, this name was made available by Isaac (1974a). To be precise, the following diagnostic statement from Isaac (1974a: 129), which also serves to explain the choice of the specific name, just barely fulfills Article 13.1.1 of the International Code of Zoological Nomenclature (ICZN 1999): “No monstrillid so small has previously been described.”

With respect to all of the new species introduced by Isaac (1974a), Grygier (1995a: 43) wrote, “The new species in this paper were diagnosed very poorly, but one feature, at least, can be taken as characteristic of each one, so all are available.” Actually, the description of Monstrillopsis sarsi Isaac, 1974a included clear statements of differences in the natatory legs and copulatory appendage (sic; = the male genitalia) from those of M. dubia ( Scott, 1904) , so the availability of M. sarsi from this work is not problematic. Isaac’s (1974a) diagnostic statements for the remaining four nominal species are quoted below, but for the fourth, Thaumaleus similirostratus , further analysis shows that it was in fact not available from Isaac (1974a), but instead was made available in one of his later works.

Thaumaleus pallidus [now Cymbasoma pallidum ( Isaac, 1974a) ]: “… the muscles of the body are the same characteristically pale grey, much lighter than those in any other monstrillid seen by the author.” ( Isaac 1974a: 132).

Thaumaleus tenuis [now Cymbasoma tenue ( Isaac, 1974a) ]: “The abdomen, especially when viewed from the side, appears to be drawn out, hence the name proposed.” ( Isaac 1974a: 134). It is perhaps debatable whether this feature was intended to be understood as a distinguishing characteristic, but the statement itself is similar in quality to that accepted for both Thaumaleus pallidus and Monstrilla minuta above. If availability from Isaac (1974a) were rejected, Isaac (1975b: 7) treated the elongate body as a distinguishing feature of T. tenuis in a key while also providing two other features distinguishing this species from T. quadridens ( Davis, 1947) , so availability would shift to this later work.

Thaumaleus striatus [now Cymbasoma striatum ( Isaac, 1974a) ]: “It is characterized by having very fine striations (only visible under high magnification) on the surface of the anterior half of the cephalothorax, running around the circumference.” ( Isaac 1974a: 135).

Thaumaleus similirostratus [now Cymbasoma similirostratum ( Isaac, 1974a) ]: “It is immediately distinguishable from any other monstrillid, with the exception of Thaumaleus rostratus ( Scott, 1904) , by the prolongation of the cephalothorax forward between the antennae” ( Isaac 1974a: 131). With regard to this latter species, only the fact that different sexes of each were available (male for T. similirostratus , female for T. rostratus ) was mentioned. With regard to the two sexes, one might argue that T. similirostratus Isaac, 1974 is unavailable under Article 11 for reason of having been proposed as a synonym, but the actual wording of the relevant proposition by Isaac (1974a: 131) was not so definite: “Only the female of T. rostratus has been described, and it is possible [our emphasis] that the specimen from the Lundy area [i.e., the holotype of T. similirostratus ] is the male of this species.” Even so, this statement, combined with a subsequent discussion of “possible resemblance” in the urosomal segmentation, and with Isaac’s statement that “The name Thaumaleus similirostratus is proposed, however, until a female T. rostatus is obtained for comparison.” (p. 131), suggests instead that the description might violate Article 11.5 (names not used as valid when proposed are not available) or 15.1 (names proposed conditionally after 1960 are not available). We consider that Isaac (1974a) did use the name as valid, but in consideration of the definition of “conditional” in the Glossary of the Code, viz., “made with stated reservations”, we conclude that T. similirostratus was proposed conditionally, and not made available from Isaac (1974a). Isaac (1975b) included this species in a key (p. 7), thus unambiguously distinguishing it from its (male) congeners, and in the list of species (p. 9) he added the notation, “Female unknown; possibly this species is the male of T. rostratus .” Since this annotation implies no conditionality, Article 15.1 does not apply and, consequently, the authorship of T. similirostratus is here formally attributed to Isaac (1975b).

Grygier (1995a: 43, 45, 56, 76) misspelled this specific name as “ similirostris ”, spelling it correctly only on p. 45, several lines below one of the misspellings. This was not a deliberate emendation and “ similirostris ” is an incorrect subsequent spelling under Article 33 of the Code. As far as we know, nobody since has adopted the spelling “ similirostris ” for this nominal species.