Agama gutturosa Merrem, 1819

Denzer, Wolfgang & Tillack, Frank, 2024, The original description of Agama gutturosa Merrem, 1819 and its nomenclatural implication on the genus Bronchocela Kaup, 1827 (Squamata: Agamidae), Zootaxa 5507 (2), pp. 337-355 : 346-348

The original description of Agama gutturosa Merrem, 1819

In contrast to the comparatively short diagnosis in Merrem (1820) and the short statement mentioned above, the species is described on pp. 165 (right column) and 166 (left column) in Merrem (1819) in more detail [our translation from German]:

“ Agama gutturosa . Goitrus Agama . Seba Thes. I. tab. 89. fig. 1. 2. Linné and later Lacepède and Daudin list this illustration as Agama Calotes ; however, with much confidence I can state that it belongs to another, by no systematicist listed species, as I had both specimens illustrated by Seba [at my disposal] from the collection of the Graf von Borcke and have described [them]. It differs from the Calotes agama by a stronger goitre [gular pouch], by the absence of spines on the occiput, by keeled scales [that are] directed backwards on the plate [top] of the head and by dorsal scales directed downwards and backwards, as well as their considerably sized scales and their keeled ventral scales from the true agama ( A. colonorum [now Agama agama ]). A gular fold is not present and the pouch, formed by the throat, extends onto the chest, and is compressed like in the iguana. That it appears thick and convex in Seba’s first figure results from cloth that it was stuffed with. The body is triangular and the back sharp; across it runs a row of soft, tooth-like blades, that are longest on the neck and continuously decrease in size towards the base of the tail and disappear on the tail itself. The colour of one specimen is light blue, that of the other grey, both underneath whitish. Whitish spots form on both sides and the legs more or less distinctive parts of irregular bands. The length is 19 Zoll, of which 15 Zoll is contributed by the tail. Teeth are moderately large, pyramidal, slightly compressed and differ from other agamids studied by me through a small tooth on each side not far from the root. According to Seba it inhabits Mexico.”

Not only is the description in Merrem (1820) much shorter, he also changed his taxonomic approach and considered Agama as a subgenus of Calotes . Consequently, he renamed the species as “ Calotes Agama gutturosa ”. As Merrem (1819) precedes Merrem (1820) this action does not pose a nomenclatural problem.

Nomenclatural consequences

In an attempt to stabilise the nomenclature surrounding A. gutturosa and A. cristatella, Figueroa (2021) discussed the matter on the incorrect assumption that Merrem (1820) and Kuhl (1820) were published simultaneously.

First, it must be acknowledged that Merrem (1819) based his description on only two specimens, namely those that came from Seba’s collection. This contrasts with his 1820 description where he listed further illustrations and descriptions that would typically constitute additional syntypes and were treated as such by Figueroa (2021). In his analysis, Figueroa (2021) designated a lectotype from what he considered the syntype series of A. gutturosa , namely Seba pl. 89 fig. 1, Iguana calotes ( Latreille 1802: 260, fig. 1 on plate facing p. 260 [now Bronchocela cristatella ]); Seba pl. 89 fig. 2 [considered by Figueroa (2021) to represent Calotes calotes ] and Agama calotes ( Daudin 1802: vol. III, 361, pl. 43 [now Calotes calotes ]).

Figueroa (2021) designated the same figure ( Seba (1734) pl. 89 fig. 1) as lectotypes for both A. cristatella and A. gutturosa . This lectotype designation complies with Art. 74 of the Code and cannot normally be undone as Art. 74.1.1 states that “no later designation of a lectotype has any validity”. But our discovery of an earlier publication puts his actions into question. Art. 72.1.1. of the Code defines the type series as “all specimens on which the author established a nominal species-group taxon”.As Figueroa (2021) was referring to “ Calotes Agama gutturosa Merrem, 1820 ” and not to the original publication, i.e., Agama gutturosa Merrem, 1819 , this has two consequences:

1. Figueroa’s (2021) lectotype designation for A. gutturosa ( Seba 1734: pl. 89 fig. 1) becomes invalid. 2. The illustrations of Agama calotes ( Daudin 1802: vol. III, 361, pl. 43) [now Calotes calotes ] and Iguana calotes ( Latreille 1802: 260) [now Bronchocela cristatella ] were not explicitly mentioned by Merrem (1819) and therefore do not qualify as syntypes. Consequently, they lose their status as paralectotypes.

In the earlier work, Merrem (1819) also listed “Seba Thes.[aurus] I tab. 89 fig. 1” under Agama gutturosa such that it qualifies as a syntype, but he clearly described the specimen in figure 2 in more detail. Already, Seba’s illustrations are unambiguously showing different species. The specimen in fig. 1 does not have a dorsal crest (see also Kaup 1827) and represents B. cristatella ; whereas the specimen in fig. 2 has a well-developed dorsal crest and does not represent B. cristatella . Merrem (1819) stated that he had both of Seba’s specimens on hand and gives the colouration for both. Therefore, although they may represent two different taxa, both specimens have the status of syntypes.

To clarify the situation and to stabilise nomenclature, we hereby designate the illustration from Seba (1734, plate 89 figure 2) as the lectotype of Agama gutturosa Merrem, 1819 according to Art. 74.1 of the Code (see Figure 1 ). Through our lectotype designation for Agama gutturosa Merrem, 1819 , the specimen in Seba’s (1734) plate 89 figure 1 becomes a paralectotype and has no longer any name-bearing function. Consequently, Agama cristatella Kuhl, 1820 , whose lectotype is the specimen in Seba’s (1734) plate 89 figure 1 ( Figueroa 2021), is not a junior synonym of Agama gutturosa Merrem, 1819 and the currently accepted name Bronchocela cristatella ( Kuhl, 1820) can prevail.

Figueroa (2021) also relied on Fitzinger’s (1843) type species designation, who he considered as the First Reviser, and designated A. gutturosa Merrem, 1820 as the type species of Bronchocela Kaup, 1827 . Fitzinger (1843) divided the genus into three subgenera ( Bronchocela , Lophodeira and Pseudocalotes ). He included A. gutturosa and A. intermedia in the subgenus Bronchocela by redefining the original genus diagnosis of Bronchocela such that A. cristatella was excluded. The latter was placed in the newly defined subgenus Lophodeira . Although Fitzinger (1843: 15) stated that A. gutturosa is the “ Typus ” of Bronchocela , this nomenclatural action is questionable if not invalid. According to Art. 69.4 of the Code, “Fixation by elimination” is excluded, i.e., “elimination of all but one of the originally included nominal species from a nominal genus or subgenus does not in itself constitute type fixation.” Note that A. intermedia was not included when Kaup (1827) erected the genus and therefore does not qualify as a type species. Fitzinger (1843) eliminated Kaup’s Bronchocela cristatella from that genus and was left with B. gutturosa as the type species. Technically, Fitzinger’s designation of A. gutturosa as the type species of Bronchocela , by elimination, must be seen as invalid. Consequently, the next available type species designation has to be taken into account. Therefore, we follow Smith (1935) who designated Agama cristatella Kuhl, 1820 as the type species of Bronchocela Kaup, 1827 .

The identity of Merrem’s specimens

A very important statement in Merrem (1819) is that he examined the specimens depicted in Seba (1734) and that they were present in the von Borcke collection. A large part of von Borcke’s collection came to ZMB in 1817 and contained two specimens identified later as Bronchocela cristatella (ZMB 680) and Bronchocela jubata (ZMB 686), respectively. In their type catalogue, Denzer et al. (1997) did not list ZMB 680 as a type and Bauer & Günther (2013) reported the B. cristatella specimen as “not located”. A new search in the collection revealed that the specimen is still present. However, ZMB 680 has its tail broken twice and does not match the illustration in Seba (1734). Furthermore, our measurements do not agree with the measurements given by Merrem (1819). ZMB 680 can therefore be excluded as the syntype depicted in Seba’s figure 1.

The B. jubata specimen (ZMB 686) was reported by Bauer & Günther (2013) as “no match to Seba figures”. We re-examined the specimen (ZMB 686) and compared it to Seba’s plate 89 figure 2 as well as to Merrem’s (1819) description and we were surprised that it was rather a good match to Seba’s plate 89 figure 2 in general appearance. In particular, the specimen agrees with Merrem’s description regarding the presence of a dorsal crest consisting of “tooth like leafs” (lanceolate scales) that decrease in height towards the base of the tail. There exist, however, some differences between Seba’s figures and Merrem’s description. The direction of the scales in Seba’s figure is backwards pointing, a character typical for Calotes spp. , instead of backwards and downwards as it is typical for Bronchocela spp. Also the tail lengths (Seba pl. 89 fig. 1 and fig.2) do not reflect their actual size (TL/SVL> 3 in B. cristatella and B. gutturosa ) as they only account for slightly more than double the snout-vent-length. We consider these differences as a lack of attention to detail by the illustrator. Both of these features were correctly described in Merrem (1819). The total length of one specimen reported by Merrem (1819) was 19 Zoll of which the tail (TL) measured 15 Zoll (1 Zoll = 1 French Pouce = 27.07 mm: 19 Zoll = 514 mm (TotL); 15 Zoll = 406 mm (TL); 4 Zoll = 108 mm (SVL); alternatively, 1 Zoll Hesse = 25 mm; 19 Zoll = 482 mm (TotL); 15 Zoll = 381 mm (TL); TL/SVL = 406/108 = 3.76). The value of 25 mm per Zoll was only introduced in Hesse (where Merrem resided) in 1821 and we assume that Merrem (1819) referred to the French measurement system. In any case, our measurements of ZMB 686 (TotL = 548 mm, SVL = 120 mm; TL = 428 mm; TL/SVL = 3.57) differ from those reported by Merrem (1819). Another feature that is discernible in Seba’s plate 89 figure 2, but not mentioned by Merrem (1819), is an unusually formed gular sac that appears to be rather spherical/globular, something that is clearly developed in ZMB 686. However, Merrem (1819) stated that the throat of one specimen (referring to plate 89 fig. 1 in Seba (1734), “der ersten” = the first) was filled with cloth such that the gular sac appeared convex. While this feature is visible in Seba (1734: plate 89 figure 1) (= A. cristatella Kuhl, 1820 ) it is much more pronounced in Seba (1734: plate 89 figure 2) (= A. gutturosa Merrem, 1819 ). Apparently, it was custom in early collections to emphasise anatomical features to produce a more “natural” live appearance. We did not find any cloth in ZMB 686 but the unnaturally formed gular pouch lead us to the assumption that it had been stuffed at an earlier stage ( Figure 2 ). As Merrem (1819) did not mention this particular feature for the specimen he considered to represent plate 89 figure 2 in Seba (1734) and because our measurements differ from Merrem’s we do not treat ZMB 686 as a syntype of C. A.. gutturosa despite its otherwise good match with Seba’s figure.

Merrem’s (1819) description of Agama gutturosa contained several characters that facilitate a comparison with currently accepted taxa. The absence of a spine on the occiput and dorsal scales directed backwards and downwards clearly differentiates the species from Calotes and places the species into the genus Bronchocela . If Merrem (1819) had Seba’s specimen at hand, then any assumption that Seba’s plate 89 fig. 2 shows Calotes calotes is therefore unfounded. The presence of a well-developed dorsal crest helps to exclude Bronchocela cristatella as this species has at best a few enlarged scales on the dorsal ridge which is otherwise serrated. Within the genus Bronchocela , other than the Javanese B. jubata , the Philippine B. marmorata and B. celebensis from Sulawesi possess an anterior dorsal crest of elongated scales. However, B. jubata is the only species where the crest runs across most of the back and decreases continuously towards the base of the tail as described by Merrem (1819). Further to this, the gular pouch of B. celebensis and B. marmorata is smaller than in A. gutturosa . Merrem’s (1819) description of A. gutturosa and the von Borcke specimen (ZMB 686) agree well with the remaining two syntypes of Bronchocela jubata (MNHN-RA 2542 and MNHN-RA 2543, see Brygoo 1988). We therefore conclude, that Merrem’s (1819) description of Agama gutturosa represents Bronchocela jubata Duméril & Bibron, 1837 .

Consequently, Agama gutturosa Merrem (1819) becomes a senior subjective synonym of Bronchocela jubata Duméril & Bibron, 1837 and would have nomenclatural priority such that the species currently known as Bronchocela jubata Duméril & Bibron, 1837 should be called “ Bronchocela gutturosa Merrem, 1819 ”. This, however, threatens nomenclatural stability as the name Bronchocela jubata has been used consistently since Duméril & Bibron (1837). In a recent publication dealing with the taxonomy of Bronchocela jubata, Amarasinghe et al. (2022) followed Figueroa (2021) and treated Agama gutturosa Merrem, 1820 as a junior objective synonym of, and conspecific with, Bronchocela cristatella in order “to uphold the taxonomic stability of a long standing nomen, B. jubata ”. Our analysis has revealed that this assumption is incorrect, and the only way to stabilise nomenclature is to reverse precedence according to Art. 23.9 of the Code ( ICZN 1999). The last use of the older name, “ Calotes (?) gutturosa ”, as valid was by Fitzinger (1860). The species epithet gutturosa has not been in use after 1899 in conjunction with either Bronchocela or Calotes apart from the mere mentioning as Agama gutturosa in a non-taxonomic and non-nomenclatural compilation of earlier published names by Sherborn (1905). We therefore consider the species epithet gutturosa /- us in conjunction with either Bronchocela (or Calotes ) as a nomen oblitum and the species epithet jubata /- us in conjunction with either Bronchocela (or Calotes ) as a nomen protectum. In support of our decision to reverse precedence we provide a list of publications in Appendix I in accordance with Art. 23.9 of the Code ( ICZN 1999). In agreement with currently accepted taxonomy, the valid name of the species remains Bronchocela jubata Duméril & Bibron, 1837 .

Figures

FIGURE 1. The original illustrations from Seba (1734). Upper panel: Lectotype of Agama cristatella Kuhl, 1820. Lower panel: Lectotype of Agama gutturosa Merrem, 1819.

FIGURE 2. Bronchocela jubata (ZMB 686, von Borcke’s specimen). Upper panel: lateral view. Lower panel: ventral view. Please note the unnaturally formed gular region.