Anthurium elsieae (Araceae), A New Species from the Eastern Amazon Domain^†

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Dear authors,

I think that your work has been carried out competently and properly. The manuscript is well written and presented and is suitable to Taxonomy. However, I suggest few corrections, mostly editorial ones, for a better understanding by future readers of the paper. So MS can be published after minor revision.

First of all, if a species is described based on a single specimen, as in your case, then such a species is called a singleton. It would be good to mention this term in the article, mentioning it in the Abstract and including in the keywords, since in plants this does not occur as often as in some animals, for example, in insects, and all cases are of interest.

Lines 72-73 The type specimen was collected in 2023. To study its complete life cycle, including vegetative development, flowering, and fruiting, a living plant was collected and cultivated ex-situ in a shade house…

This section is followed by the Diagnosis, which states that Fruits not seen, and only then, in the Discussion, does it state that neither flowers nor fruits were produced during cultivation. I believe, for the sake of clarity, it would be more appropriate to `report this immediately in Section 2.2. Collection and Morphological Analysis.

Line 75 Vegetative and reproductive structures were measured from fresh material and dried herbarium specimens.

If there was one sample, what does here the plural "specimens" mean? Were these parts of the same plant?

Line 203 No population size estimates are available.

Since there was only one sample, it is hardly worth writing about the population.

Line 209 Fig.2B

In Fig. 2B, we see a potted plant (cultivated?) with an inflorescence. Is this a collected specimen soon after planting? Would it be worth clarifying?

Best wishes

Author Response

We thank the reviewer for the careful and constructive comments and for recognizing the quality of our work. Below we address each point point-by-point.

General comment – Singleton
Comment: If a species is described based on a single specimen, as in your case, then such a species is called a singleton. It would be good to mention this term in the article, mentioning it in the Abstract and including in the keywords, since in plants this does not occur as often as in some animals, for example, in insects, and all cases are of interest.

Response: We agree with the reviewer. The term "singleton" has been added to the Abstract and Keywords, as well as to the Introduction, where we now explicitly state that the new species is described based on a single fertile individual. The reference Lim et al. (2012) has been cited accordingly.

Lines 72-73 – Ex-situ cultivation and fruiting
Comment: The type specimen was collected in 2023. To study its complete life cycle, including vegetative development, flowering, and fruiting, a living plant was collected and cultivated ex-situ in a shade house… Unfortunately, the new plant does not fruit in cultivated ex-situ; we have only observed the flowering phase until now.

Response: We thank the reviewer for raising this point. We have clarified in the text (Section 2.2. Collection and Morphological Analysis) that fruiting has not been observed either in the field or in cultivation. Only the flowering phase has been documented, based on the type collection (June 2024 and September 2025). The manuscript now states this clearly.

Diagnosis – Fruiting information
Comment: This section is followed by the Diagnosis, which states that Fruits not seen, and only then, in the Discussion, does it state that neither flowers nor fruits were produced during cultivation. I believe, for the sake of clarity, it would be more appropriate to report this immediately in Section 2.2. Collection and Morphological Analysis.

Response: We agree. The information that fruits were not observed has been moved to Section 2.2. Collection and Morphological Analysis, immediately after the description of the cultivated plant. The Diagnosis now simply states "berries not observed" without repetition. The Discussion has been streamlined accordingly.

Line 75 – Plural "specimens"
Comment: If there was one sample, what does here the plural "specimens" mean? Were these parts of the same plant?

Response: We appreciate the clarification. We collected two samples: one for cultivation (living plant) and one for the herbarium (dried specimen). The manuscript has been revised to state: "We collected two samples: one for cultivation and one for the herbarium." The plural "specimens" refers to these two preparations from the same individual.

Line 203 – Population size estimates
Comment: Since there was only one sample, it is hardly worth writing about the population.

Response: We agree and have revised the text. The sentence "No population size estimates are available" has been removed. We now state directly: "Only one fertile individual was found; therefore, no population size estimates can be provided." This is more accurate and transparent.

Line 209 – Figure 2B (potted plant)
Comment: In Fig. 2B, we see a potted plant (cultivated?) with an inflorescence. Is this a collected specimen soon after planting? Would it be worth clarifying?

Response: We thank the reviewer for this observation. We have added a clarification in the Figure 2 caption, stating that the photographed individual is the cultivated ex-situ plant, approximately three months after planting, already producing an inflorescence. The revised caption now reads: "(B) cultivated ex-situ plant (three months after planting) showing habit and inflorescence."

Reviewer 2 Report

Comments and Suggestions for Authors

This paper describes a new species of Anthurium (Araceae), Anthurium elsieae, discovered in the state of Amapá, eastern Brazilian Amazon. The discovery fills a taxonomic gap in the genus and provides a useful reference for the diversity conservation and taxonomic research of Anthurium. The morphological description is detailed, the species delimitation is clear, and the manuscript generally conforms to the publication requirements of the journal Taxonomy. It is recommended to publish after revision. The detailed comments are as follows:

1. There is an inconsistency between the petiole length given as < 10 cm in the abstract and 10–13 cm in the detailed morphological description; these values must be unified.
2. A comparative table of diagnostic morphological characters between the new species and its two closest congeners is strongly recommended, including number of leaflets, coloration, petiole length, collective vein position, spadix length, and other key traits.
3. Flowering of Anthurium elsieae is only documented in June and September; information on the duration of the flowering period is suggested to be added.
4. The survey coverage for Anthurium elsieae is not indicated; are there any other potential distribution localities? This information should be clarified.
5. All measurements must be explicitly labeled as being taken from fresh material or dried herbarium specimens.
6. The captions for Figure 2 and the line drawing are incomplete and lack scale bar indications.
7. The latitude and longitude range should be added to Figure 3.

Author Response

Response to Reviewer 2

We thank the reviewer for the careful and constructive comments. Below we address each point.

1. Petiole length inconsistency

Corrected. The abstract now reads "petiole 10–13 cm long," consistent with the morphological description.

2. Comparative diagnostic table

A comparative table (Table 1) has been added after the diagnosis, comparing A. elsieae with its morphologically closest Brazilian species of section Schizoplacium.

3. Flowering period duration

Flowering was recorded in June 2024 and September 2025. The full duration of the flowering period remains unknown due to limited field observations; this has been clarified in the text.

4. Survey coverage and potential distribution

The species is currently known only from the type locality (Ramal do Piquiá). However, given the proximity to the Flota do Amapá and the presence of similar habitat, additional populations may occur within the protected area. The manuscript has been updated accordingly.

5. Measurements from fresh or dried material

Vegetative measurements (petiole, leaf blade, petiolules) were taken from fresh cultivated material. Floral details (tepals, stamens, gynoecium) were measured from dried herbarium specimens. This information has been added to the Materials and Methods section.

6. Figure 1 and Figure 2 scale bars

Both figures already contain scale bars within the images. The captions have been revised to indicate this.

Reviewer 3 Report

Comments and Suggestions for Authors

Dear Editor,

I have reviewed the work, "Anthurium elsieae (Araceae): A New Species from the Eastern Amazon Domain," and I consider the research suitable for publication in Taxonomy.

Below, I present some questions related mainly to the identification key. While the authors argue for leaf plasticity in Anthurium, they use characters without confidence intervals in some steps. While this can be discussed in the comments for field recognition, the key contains sufficient reproductive characters for identification.

On line 63, cite Figure 3 in the description of the study area.

On line 77, the authors argue for isotype deposition in UB and RB; however, line 87 does not provide isotype guidance.

Line 87: Insert isotypes.

The diagnosis should include a brief comparison with the morphologically closest species. There is no need to repeat this in the comments, where auxiliary characters can be better explored for species recognition in the field.

Line 131: Anthurium flowers are dimerous and consist of an outer whorl with two lateral tepals and an inner whorl with two other tepals (anterior and posterior). Please see the details at doi.org/10.7717/peerj.2929.

Identification Key:

Step 3: There is overlap regarding the visibility of the collecting vein. Leave only the distance from the margin.

Step 4: There is overlap regarding the length of the petiolules (less than 1.0 cm vs. greater than 0.5 cm). Please remove them.

Step 5: There is no confidence interval between the number of leaflets and the number of primary lateral veins. Please remove them. Furthermore, it is unnecessary to include the fruit shape of A. zelesskii, as the fruit of A. elsieae was not observed.

Step 6: There is no confidence interval between the number of leaflets and primary lateral veins. Please remove this information.

Combine the information from the "Description of Area" section with the "Phenology, Distribution, Habitat, and Conservation status" section.

On line 197, replace "... habitat conservation status" with "... habitat and conservation status."

Figure 3: Although the authors argue that the species occurs within the Flota Amapá, its distribution point is outside the protected area's polygon. Please explain. Was the collection done in the buffer zone?

I congratulate the authors and thank them for the opportunity to review the manuscript.

Author Response

We thank the reviewer for the careful evaluation and constructive suggestions. Below we address each point point-by-point.

General comment – Identification key and leaf plasticity
Comment: While the authors argue for leaf plasticity in Anthurium, they use characters without confidence intervals in some steps. While this can be discussed in the comments for field recognition, the key contains sufficient reproductive characters for identification.

Response: We thank the reviewer for this observation. We have revised the identification key as suggested, removing overlapping characters and those without clear confidence intervals. The key now relies more heavily on reproductive characters, which are more stable for species discrimination.

Line 63 – Cite Figure 3
Comment: On line 63, cite Figure 3 in the description of the study area.

Response: We have added the citation of Figure 3 in the description of the study area as requested.

Line 77 and 87 – Isotype deposition
Comment: On line 77, the authors argue for isotype deposition in UB and RB; however, line 87 does not provide isotype guidance. Line 87: Insert isotypes.

Response: We thank the reviewer for this observation. We collected only the holotype (one single fertile individual). No isotypes were deposited. We have removed the statement about isotype deposition in UB and RB from the manuscript to avoid confusion.

Diagnosis – Comparison with closest species
Comment: The diagnosis should include a brief comparison with the morphologically closest species. There is no need to repeat this in the comments, where auxiliary characters can be better explored for species recognition in the field.

Response: We agree. The diagnosis now includes a brief comparison with the morphologically closest species (A. brevipedunculatum, A. pentaphyllum, A. eminens, A. petiolicarinatum, and A. zalesskii). Auxiliary characters have been moved to the comments section for field recognition.

Line 131 – Flower morphology (dimerous)
Comment: Anthurium flowers are dimerous and consist of an outer whorl with two lateral tepals and an inner whorl with two other tepals (anterior and posterior). Please see the details at doi.org/10.7717/peerj.2929.

Response: We thank the reviewer for this correction. The flower description has been revised accordingly.

Identification key – Specific steps
Comment - Step 3: There is overlap regarding the visibility of the collective vein. Leave only the distance from the margin.

Response: Corrected. Step 3 now refers only to distance from the margin (ca. 2 mm vs. >2 mm).

Comment - Step 4: There is overlap regarding the length of the petiolules (less than 1.0 cm vs. greater than 0.5 cm). Please remove them.

Response: Corrected. Step 4 now uses only petiolules absent (sessile) vs. petiolules present (>0.5 cm) with no overlapping ranges.

Comment - Step 5: There is no confidence interval between the number of leaflets and the number of primary lateral veins. Please remove them. Furthermore, it is unnecessary to include the fruit shape of A. zalesskii, as the fruit of A. elsieae was not observed.

Response: Corrected. We have removed the number of leaflets and primary lateral veins from Step 5. We have also removed the fruit shape of A. zalesskii since fruits of A. elsieae were not observed.

Comment - Step 6: There is no confidence interval between the number of leaflets and primary lateral veins. Please remove this information.

Response: Corrected. Step 6 now omits the number of leaflets and primary lateral veins.

Section reorganization – "Description of Area"
Comment: Combine the information from the "Description of Area" section with the "Phenology, Distribution, Habitat, and Conservation status" section.

Response: We agree. The "Description of Area" section has been combined with "Phenology, Distribution, Habitat, and Conservation Status" into a single section for better readability.

Line 197 – Comment: On line 197, replace "... habitat conservation status" with "... habitat and conservation status."

Response: We changed it. 

Figure 3 – Location outside Flota Amapá
Comment: Although the authors argue that the species occurs within the Flota Amapá, its distribution point is outside the protected area's polygon. Please explain. Was the collection done in the buffer zone?

Response: We thank the reviewer for this observation. We confirm that the collection point of Anthurium elsieae is located outside the official polygon of the Flota do Amapá. The species was collected at: Amapá, municipality of Amapá, Ramal do Piquiá, INCRA Settlement. This site is in the surroundings of the Flota do Amapá, not within its boundaries nor in its formal buffer zone. We have corrected the manuscript to state that the species occurs "near the Flota do Amapá" rather than within it. The text has been updated to: "Anthurium elsieae is known only from the Ramal do Piquiá, INCRA Settlement, municipality of Amapá, state of Amapá, Brazil, near the Flota do Amapá."